tag:blogger.com,1999:blog-77408862667062121342024-03-16T02:28:15.561-07:00Brian Zweerink's Awesome BlogBrian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-7740886266706212134.post-50012412946571849782022-05-22T17:21:00.000-07:002022-05-22T17:21:59.694-07:00Taking a high school Trigonometry class<div><i>Note: I wrote this post a few years back, but I forgot to hit the publish button, I guess.</i></div><div><br /></div>For a lot of reasons, I've been wishing my trigonometry skills were up to par recently. My lack of knowledge has specifically held me back from solving a few design problems, and there is also the possibility that I can offer my Digital Electronics students a math credit if I could pass the test formerly known as the Praxis, and get my high school math certification. For those of you who don't know, I currently teach high school Computer Aided Drafting, Project Lead the Way engineering classes, and a wood shop class. This year my conference period landed on an hour in which trig was taught, so I asked the teacher if she would mind if I sat in, and now here I am taking high school trigonometry in sixth period. <br />
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I wanted to document some of my thoughts here, because it's a weird feeling taking a high school class as an adult, and I'm getting some insights into the life of a high schooler that I'm not getting by merely teaching classes.<br />
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It's hard.</h2>
OMG it's hard. Maybe my classmates have it easier because they all just came out of Algebra 2, but I'm struggling with just the basic algebra side of things, much less the trigonometry. We're learning the <a href="https://en.wikipedia.org/wiki/Pythagorean_trigonometric_identity" target="_blank">Pythagorean Identities</a> and if we go slowly I can keep up, but I have to keep referencing knowledge that I just learned yesterday, and it becomes confusing quickly. It takes too long to understand everything back to the root knowledge, so I have to just memorize waypoints, but when I use memorized knowledge I forget what it all means. My brain is not used to working this hard.<br />
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I'm doing about an hour of homework a day, too. Plus, I'm giving up my conference period, which means I have about an hour of teacher stuff to do at the end of each day, so this class is costing me two hours a day total. None of that is a really big deal at this point in the year, but it may be trouble later. My primary thought on this though is that these students are probably working this hard in most of their classes. Could it be possible that they have 3 hours of homework a night? I'll have to ask a few of them. As an electives teacher I never give homework so students can concentrate on their non-electives class homework, and this experience is reinforcing that decision.<br />
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Where are the girls?</h2>
My trigonometry class has a perfect 50-50 split of boys and girls, and of the 7 boys in the class, 6 of them are in my CAD 2 or Digital Electronics classes. Exactly zero of the girls are in any of my classes. What's going on here? Most of my students don't take trig, so I'm always excited to get the students who do, and it seems like the easiest way to get more trig students would be to get the girls too. There seems to be a relationship between advanced math boys and mechanical/electronic engineering. Why does this relationship not exist for the girls? What electives are the girls taking? I need to find out.<br />
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Do I need to raise my hand to go pee?</h2>
The other day I needed to use the bathroom during class, but I didn't know what the protocol for asking permission was. I just held it. <br />
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<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com0tag:blogger.com,1999:blog-7740886266706212134.post-61729827843182930432020-05-11T13:21:00.000-07:002020-05-13T07:33:43.830-07:00NICA Parent's First Mountain Bike Buying GuideThe National Interscholastic Cycling Association, or NICA, is exploding in popularity, and I've seen a lot of parents buying their kids their first mountain bike lately. In almost every case I've seen those parents make the same mistake of not buying a bike that's going meet the needs of their young rider, even in the short term, and I wanted to lay out some guidance as a second-season NICA dad, a former bike shop mechanic, and as a newer mountain biker myself. Before we get started on what you should be thinking about when picking out your first mountain bike, I want to lay out some basic truths:<br />
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1) Any bike is better than no bike, and I've seen some student athletes do very well in races on low-end bikes. You can always buy a better bike later. Your bicycle is not a tattoo; bikes are temporary. I'm not here to shame anybody into buying more bike than they can afford, but I do think that too many parents are not buying what they should be buying out of fear that their kids won't be into it long term, or that the more expensive bikes and features aren't worth it, or that they won't be appreciated by a new rider. The very opposite is true in each of those cases, to a point. A new rider will absolutely and instantly feel the difference between those bikes, and that difference will manifest itself as a desire to ride their bike more. It's no fun to ride a no-fun bike. </div>
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2) I think there is a perception that the difference between a $600 entry level bike and a $1500 bike is the difference between a Honda and a Ferrari, but in reality it's the difference between a 1984 Chrysler K-Car and a modern Honda Civic. That K-Car will get you to work, and they sold millions of them, but you're not going to drive them for fun, and they're not going to inspire a love of driving. They're not safe or reliable, and they were designed when the national speed limit was 55 mph.</div>
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3) The kind of riding that NICA is geared towards is most likely not the kind of riding your kid wants to do. Cross country NICA riding is a wheels-on-the-ground affair, and any opportunities to catch air on the NICA race courses are typically roped off. Let me tell you right now, your kid wants to jump. Luckily for your your kid, amazing flow trails with beautifully sculpted jumps are being built across the country at record pace. Unluckily for you though, the entry-level bikes that are made for those trails are somewhat more expensive than the entry-level cross country bikes. Since all good bikes are expensive anyway, and since you're probably not going to buy a different bike for each of those disciplines, and since there's no cash prizes for winning a NICA race, and since your kid probably isn't going to win even with an expensive cross country bike anyway, I'm going to recommend that you buy a bike that's capable of doing what your kid wants most. You'll get more use out of it, and it will inspire a love of riding that will last forever. </div>
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With that being said, here's my list of must-have features on an entry-level mountain bike:</div>
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<b>A dropper post.</b> Don't buy a bike without a dropper post. The only situation I can think of in which you might not want to buy a dropper post is if your kid is coming in first place in track and cross country running events, and you think your kid might <i>only</i> be interested in pure speed. Otherwise, that dropper post is going to make all other kinds of riding more fun, and by a significant amount. A dropper post is like an office chair, which will lower when you're sitting and pull the handle, and raise when you pull the handle and take your weight off of it. This allows you to have your seat all the way up for uphills and fast flat riding, and instantly lower it for jumps and technical descents. Do not buy a low-end bike without a dropper post thinking you will add one later, even if the bike has internal cable routing for a dropper post already. <i>You won't</i>, and if your bike came with a front derailleur then it's shifter is going to be in the way of the dropper lever, and the expense of converting a low-end bike to a 1x system so you can add a dropper post isn't usually worth it.</div>
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<b>A 1x drivetrain.</b> All the cool kids are riding 1x these days, and for a good reason. 1x drivetrains (pronounced "one-by") don't have a front shifter or derailleur, but instead have 9, 10, 11, or even 12 gears in the back and a single (1x) chainring in the front. They typically shift better, are lighter, allow you to put a dropper post lever where the front shifter would have been, but most importantly they're just easier and more fun to ride. Thinking about when you should use your front shifter and when you should use your rear is just gone. </div>
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<b>A clutched rear derailleur.</b> Because of the increase in popularity of 1x drive trains, rear derailleurs must move from tiny rear gears to absolutely dinner-plate sized gears in the rear, so they have a lot of travel. What the gear train manufacturers have done is to make that rear derailleur so that it doesn't flop around when you hit a bump. You might remember that on your old bike you could take the jockey wheels of the derailleur and pull them up and forward, which makes the chain all floppy on the underside. For reasons I don't fully understand, clutched derailleurs don't do that very easily and it keeps that long travel derailleur and chain from smacking against the bottom of your bike frame on jumps and bumps. You won't realize how bad you need a clutched rear derailleur until you've ridden one. I'm pretty sure almost all 1x drivetrains come with clutched rear derailleurs, but check to make sure. </div>
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<b>A quality air fork, with adjustable rebound dampening.</b> Do not buy a bike with a spring fork and no rebound dampening. They are jarring, klunky, and loud. Your hands will go numb, they're heavy, and you will not have as much control over your bike in bumpy terrain. You will not be happy after the first month of riding. </div>
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<b>Hydraulic disk brakes.</b> Even the worst hydraulic disk brakes of today are so much better than the rim brakes of old, and the cable actuated disk brakes of not-that-long-ago. I'm not sure if you can even buy a new mountain bike without hydraulic disk brakes these days.</div>
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Those are my must-haves, even for a brand new mountain biker, and looking over Trek's website their cheapest new bike that meets those requirements is a Trek Roscoe 7, at $1,260. I see so many parents buying their new mountain bikers a Trek Marlin 5 at $550, and that's a mistake. The derailleurs are Shimano Tourney, and that's literally department store bike level stuff. The fork is not made for off road use, but called by its manufacturer (Suntour) a "metropolitan" fork. I made the same choice that so many other people make. That was the first bike I bought my son, and a few years later that was the first bike I bought myself. It was an OK choice for my son because he was still small and was not just his first mountain bike, but his first real bike at all. It would not be appropriate for a high school student. I was instantly disappointed in mine, and within a year I had spent significantly more on my next bike (a Remedy 8 at $4,000). My son now rides a Trek Roscoe 8 at $1,790, which he absolutely loves (and spends about 6 hours a day on), but is not a particularly fast cross country bike for NICA races. I know a lot of people who use their Trek Stache as a playful all-purpose fun bike, and also race them. In fairness, I should say that I saw a student athlete place in the top 5 of the 9th grade race in Bentonville, AR on a Marlin 5, and he looked like he was having a great time, but I'll bet he upgrades soon.<br />
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I want to also list a few other considerations that I don't consider must-haves exactly, but I want you to be prepared to know about them when you're out shopping for a new bike.<br />
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<b>Tire size:</b> You used to ride a mountain bike that had 26" wheels. ALL mountain bikes had 26" wheels for many, many years. These days you can't buy a 26" wheeled mountain bike. It's all either 27.5" (also called 650b) or 29". Which one is best is hotly debated, but it is generally considered that 29" is faster, and 27.5" is more nimble, but even that is debated. You will be blown away by the improvement these wheel sizes have over 26" wheels.<br />
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<b>Tubeless tires:</b> All better mountain bikes will have tires and wheels that are ready to run without tubes, but when you buy them in the store they will be sold with tubes in them. It's easy to take the tubes out, and convert them to tubeless, and you will spend a lot less time on the side of the trail patching tubes, and you will get better traction as well. It does make changing tires a bit more of a process, but it's not that big of a deal. I would almost call this a must-have for NICA racing, since the rules do not allow anyone to help your rider change their tires on the course, and tubeless greatly reduces the chances of a flat.<br />
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<b>Thru-axles:</b> On your old mountain bike you used to have quick release skewers. At first glance it will look like modern mountain bikes have quick release skewers, but they don't. They have thru-axles. A thru-axle is much thicker, stiffer, and screws into threads cut into the frame, which keeps everything perfectly aligned so disk breaks don't rub, and adds stiffness to the frame and fork. This means if you have a roof-mounted bike rack that attaches to your forks, you will need an adapter or a different bike mount.<br />
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<b>Head tube angle:</b> Geometry of modern mountain bikes is nothing like the geometry of that old bike you used to ride back in the 2000s. One of the most important differences is the head tube angle. Modern mountain bikes have forks that stick out like old motorcycle "chopper" bikes (although not so obviously). This angle is measured between the fork and horizontal (like the ground), so the lower the angle the farther the fork will stick out. A fork with a low angle (like in the mid 60s) is called "slack" and a fork with a high angle (somewhere in the low 70s) is called "steep". Steep bikes are considered more nimble (bordering on twitchy) and slack bikes are slower to turn, but are more stable. Your kid will crash a slack bike less often when jumping.<br />
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<b>Rear suspension:</b> If price is any concern at all, I would avoid a bike with rear suspension as a first bike for a NICA racer. Unless you spend significantly more money they will be heavier than a hardtail mountain bike. Furthermore, a hardtail will develop better bike handling skills and will require less maintenance, and you can put that rear suspension money into better components.<br />
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Where does this leave you, considering your first real mountain bike purchase for your offspring? Well, if you can, spend as much as possible on your bike. Buying used can be a great choice, and should be considered as an option before buying new. You can get a lot more bike that way, but I still wouldn't buy anything more than 5 years old. Mountain bikes are experiencing a revolution in quality and innovation since about 2016 that is truly useful and valuable. Also, check with your bike shop about NICA discounts, which can be as high as 25% off a new bike. <br />
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One last thing: I would consider also buying a cheap "beater" bike for your kid to ride around the neighborhood and leave laying on its side in their friend's front yard while they play Minecraft in the basement during a rainstorm. A $1,500 bike is too valuable for this kind of task.</div>
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Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com5tag:blogger.com,1999:blog-7740886266706212134.post-18262324600296385062020-03-06T14:57:00.000-08:002020-03-06T15:10:02.960-08:00Easier Way to Make Involute Bevel Gears in Autodesk InventorI have a long-winded way to make working bevel gears with involute tooth shapes for 3D printing <a href="http://brianzawesomeblog.blogspot.com/2016/01/creating-involute-bevel-gears-in.html" target="_blank">here</a>, but it's so long and such a pain in the butt that I thought an easier way is in order, so I streamlined the process. I'm using Inventor 2019, by the way. Here we go:<br />
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1) Make a new assembly and save it.<br />
2) In that new assembly click the Design tab, then click Spur Gear.<br />
3) Click the More Options >> button in the bottom right corner to expand the Spur Gears Component Generator window down.<br />
4) Change Size Type to Module (if you're in my CAD 2 class, otherwise feel free to use Diametral Pitch). Change the Input Type to Number of Teeth.<br />
5) Change Design Guide to Center Distance. Make sure the Internal checkbox is not checked. Use a pressure angle of 20°, and a Helix angle of 0°. Change your Module to 1mm, which is the smallest teeth I get a good result with on my 3D printer.<br />
6) Type in the number of teeth you want on your smaller gear in the Gear1 area, then type in the number of teeth you want on your larger gear in the Gear2 area.<br />
7) Hit Calculate. If you hit the little >> bar on the right side of the window it will show you data about the gears it's going to make.<br />
8) Click OK. It will give you an error. I've never had it not give me an error that says my gears won't work, but they always seem to anyway.<br />
9) Inventor will put your gears in the assembly. The teeth are not involute and overlap the teeth on the mating gear, so you can't use these parts in real life.<br />
10) Right click on either of these gears and then choose Export Tooth Shape.<br />
11) Choose the Pinion to export (which is Gear1).<br />
12) If your 3D printer makes parts slightly too large (mine does) you will want to change your Normal Backlash to .006, which is the largest Inventor will allow you to enter with a module of 1mm.<br />
13) Hit ok.<br />
14) Inventor will make an extrusion of a circle with a sketch on the end of it showing the space between the teeth. Delete that extrusion, but leave the sketch.<br />
15) Edit that sketch and delete the construction line circles (but not the solid outside circle).<br />
16) In that sketch make a circular pattern of the space-between-the-teeth-shape, for however many teeth you have.<br />
17) Trim the outside circle between each tooth so that it looks like a gear.<br />
18) Finish that sketch.<br />
19) Click the Manage tab.<br />
20) Click Parameters.<br />
21) Click Add Numeric.<br />
22) Type OtherGearTeeth as the new parameter name. No spaces. Capitalization is important.<br />
23) Click the Unit/Type cell in that row, click the + next to Unitless, then choose Unitless (ul) and click OK.<br />
24) In the Equation cell for that row, type in the number of teeth in the OTHER gear. You will notice that there is already a parameter called NumberOfTeeth with the number of teeth in THIS gear, so make sure you enter the number of teeth in the gear that this gear is going to mate with.<br />
25) Click Done.<br />
26) Make a new sketch on the YZ Plane (which can be found under the Origin folder in the Model bar on the left side of the screen).<br />
27) You should see the side of your gear sketch going through the origin, so it will look like a dotty line running up and down.<br />
28) Now you are going to draw the following lines:<br />
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Make sure you don't accidentally make the two green lines perpendicular to each other.<br />
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29) Use the following picture to place the next 4 dimensions. You can cut and paste these formulas into your dimension editing boxes.<br />
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29a) The angle between the left angled line and the centerline is:<br />
90-(( 90 deg - atan(OtherGearTeeth / NumberOfTeeth) ) / 2 ul)<br />
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29b) The angle between the construction line and the centerline is:<br />
90 deg - atan(OtherGearTeeth / NumberOfTeeth)<br />
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29c) The diameter between the centerline and the very bottom point of the two solid lines is:<br />
HeadDiameter + .001<br />
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29d) The diameter between the centerline and the bottom of the construction line is:<br />
PitchDiameter<br />
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30) Everything should be fully constrained now, so finish your sketch.<br />
31) Revolve that triangle around the centerline.<br />
32) Click Start 3D Sketch.<br />
33) Click Project to Surface.<br />
34) The "gear sketch end" of your cone is the Faces, and the sketch of the gear is the Curves. You can just click on the end of the cone, but you have to use a bounding box to select the gear sketch. It seems to work best if you don't include the entirety of the near end of the cone in the bounding box along with the gear sketch. Click OK.<br />
35) Click Finish Sketch.<br />
36) Click Axis and make an axis right through the middle of the cone.<br />
37) Under Point, choose Intersection of a Plane/Surface and a Line, and make the surface the "non-gear-sketch-end" of the cone, and the line will be the axis you just made through the middle of the cone.<br />
38) Click Loft, and as your first sketch choose the projected 3D sketch of the gear, and as your second sketch choose the point we just made at the other end of the cone.<br />
39) Sometimes Cut works for the loft, and sometimes Intersect works, and I can't tell why it's not consistent, but one or the other will work. You may have to try it both ways. I try Intersect first usually.<br />
40) Now you have a bevel gear. You will need to trim it up to get it to fit into your model, but it should have the correct teeth. Don't forget to save your work!<br />
41) The process is exactly the same for the mating gear, but remember when you're adding the OtherGearTeeth parameter for the second gear, you won't type the same number of teeth into it as you did this time (unless both gears have the same number of teeth)<br />
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<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com4tag:blogger.com,1999:blog-7740886266706212134.post-91850001464478146022018-12-26T19:39:00.000-08:002019-03-21T06:12:20.883-07:00Upgrade your Trek Marlin to a Suntour Raidon front fork!<i>Here's the TL;DR for this post: I bought a 2019 Trek Marlin 5 and realized the fork sucks. I used Suntour's upgrade program to buy a new Radion XC-LO-R fork for $200 and I'm thrilled with it.</i><br />
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I recently got into mountain biking after being out of the bike scene since about 2004, when I was a full-time bike mechanic for a few years. I haven't ridden at all in about 15 years, and even back then I ended up selling my Cannondale F600 because there weren't any good trails to ride around here (Springfield, MO) and the road biking was so good. A few years back I bought my son his first good bike, a 2015 Trek Marlin 5. This last year we visited the Crystal Bridges Museum of American Art in Bentonville, Arkansas, and as we walked from downtown to the museum we saw the All-American mountain bike trail, and were blown away. Have you seen it? Insane. It turns out Bentonville is packed with amazing trails, and more importantly it turns out that there's a really nice new mountain bike park near my town, the Two Rivers Bike Park. I dug out an ancient Trek 800 with solid forks and cantilever brakes from the '90s my neighbor had given me and we went riding the next day.<br />
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It was pretty awesome, but my arms were so badly vibrated that I couldn't feel them for an hour afterward. Still, I was worried that I wouldn't be into mountain biking enough that I would do it long-term, so I mostly rode that bike with my son for about a month, before breaking down and buying my own Trek Marlin 5. I had ridden his on the beginner and intermediate downhill trails, and it was so sweet. I could ride so much faster, more comfortably, and with better control on his, even though it was a bit too small. When I took mine out on the trails it was a great improvement over the old Trek 800, but I was distinctly disappointed in its performance compared to my son's bike.<br />
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Mostly my experience consisted of my front shock (a Suntour XCE 28, which comes stock on the 2019 Marlin 5) klunking loudly as it topped out (which is like, always), and bouncing around like a pogo stick. The ride was not plush in any way. There is absolutely no dampening, and of course no rebound adjustment. I was kicking myself because I hadn't even test-ridden the bike, as I assumed it would be like my son's. His front forks were nothing to write home about (Suntour M3030, described on the Suntour website as a "<a href="https://www.srsuntour.us/collections/forks/products/m3030?variant=27528548099" target="_blank">metropolitan</a>" fork), but at least they didn't make machine-gun klunking noises like mine did when riding over rough terrain.<br />
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I decided I would upgrade, but dang! Good shocks easily cost more than my whole bike. Good shocks seemed to require a tapered head tube, which I didn't have, or even know what that meant. Disappointment. Despair. I desperately considered adding some kind of dampening myself. Then on a forum somebody mentioned the <a href="https://www.srsuntour.us/pages/upgrade" target="_blank">Suntour Upgrade Program</a>. You can upgrade your Suntour forks to a nicer fork, and on the forums it was told that Suntour offers an actually decent air-spring fork with adjustable rebound and a lockout with a 1-1/8" non-tapered steerer tube. <a href="https://www.srsuntour.us/collections/forks/products/raidon-xc-lo-r?variant=27529038787" target="_blank">The Raidon</a>! I had to prove that I was the original purchaser of the crap fork, but my bike shop printed me a new receipt for that, and for $199.95 and free shipping I was the new owner of a non-crap fork.<br />
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When it came in the mail I cut it off at the same length as my old one, transferred over the lower bearing race, and installed it. I turns out you can buy a fork pump to adjust the fork air pressure more easily than what I did, which was to over-inflate the fork and bleed off pressure until it feels good, but whateves.<br />
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Before I installed it, I noted how heavy the XCE 28 felt in comparison to the Raidon, so I pulled out the postal scale and weighed them.<br />
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6 pounds and 3.4 ounces! Obscene!<br />
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Now for the Raidon:<br />
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That's more like it! 4 pounds and 6.6 ounces, a nearly two pound weight savings! Sweet!<br />
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The whole point of this post is that I took it riding today, and it is like having a whole new bike. I absolutely can not recommend this upgrade enough. I was easily faster, jumped higher, landed softer, and had more control and comfort than ever. I could be wrong, but as far as I can tell, the lowest end bike Trek sells with an actual air fork is the X-Caliber 8, for $1,200. I feel like this makes the Marlin 5 at $540 plus $200 fork upgrade a really good deal. I realize the X-Caliber has a lot else going for it, but still.<br />
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When I was a bike mechanic I got to talk to a lot of customers, and I would always focus on how much fun a bike/part/upgrade was. Most of us are buying fun at the bike shop. Can you ride a Wal-Mart bike on the trails? Yep. Will it be a fun enough experience to make you want to go back the next day? That's a lot less likely. This fork easily passes my fun test.<br />
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While we're talking about the Trek Marlin 5, I want to offer a few of my other, non-fork related thoughts on the subject. <b>Firstly</b> I wish I hadn't bought a bike with a freewheel cassette. Most modern bikes have the ratcheting mechanism in the rear hub, not in the gear cluster like the Marlin 5 has. I could have upgraded to the Marlin 6 to get the freehub, which has unlimited upgrade potential as far as rear gearing and derailleurs go, but I didn't pay enough attention at the time. The thread-on freewheel gear cluster has no upgrade potential, and now I'm stuck with 7 gears in the rear until I upgrade my whole rear wheel. <b>Secondly</b>, the rear Tourney derailleur is awful. The main problem is that the spring in it is weak, the body of it is heavy, and so it klunks against the gear cluster when I hit bumps. It's almost as annoying as the topping out of the crappy old forks. Additionally, it often changes gears on its own when I come down from a drop or jump. I upgraded to an Alivio rear derailleur, which is two or three steps up from a Tourney, and for just $36 that tells you how cheap the Tourney must have been. The klunking and mis-shifting is gone. It's a noticeable improvement. <b>Thirdly</b>, I'm pretty happy with the wheels, especially for how cheap the bike was, but I really wanted to convert it to tubeless, which I did with the stock wheels and tires. You can see the process <a href="https://youtu.be/uBF7u2iYWgo" target="_blank">here</a>. After that, I upgraded the tires to Maxxis 2.20 DHF and DHR tires, and they fit. <b>Fourthly</b>, the brakes on the Trek Marlin 5 are awesome. My son's 2015 Marlin 5 has disk brakes too, but they are cable-controlled mechanical jobs. Mine are hydraulic and the difference is huge. Back when I was a mechanic in the early 2000's I remember the early adopters of hydraulic disk brakes always bleeding them and endlessly tinkering, so I was hesitant, but apparently times have changed. These aren't even near top of the line brakes, but I love them. <b>Fifthly</b>, I'm seriously considering converting to a 1x10 drive system. I would need a new rear wheel with a freehub, a new 10 speed cassette, a 10 speed shifter, a 10 speed chain, a narrow-wide front chainring, a crankset that would fit a new chainring (current crankset has riveted chainrings), and a bottom bracket that would fit a modern crankset. That sounds like a lot, but I'm pretty sure it could be done for about $350. I guess at that point I really am into the X-Caliber 8 price range, but as a former bike mechanic it's pretty appealing. Edit 3/21/19: I've pretty much given up on converting to a 1x system on this bike, but rather I'm saving up for a different bike. I'm currently deciding between a Roscoe 8, a Stache 7, or a Fuel EX 8. <b>Sixthly:</b> A good upgrade for the front derailleur is the Shimano FD-M313, which is no longer made, but are still available. Don't get a low mount front derailleur, as they will interfere with larger tire choices, but rather the M313, which is a high mount and doesn't take up so much space behind the seat tube. It's cheap and solved most of my chain suck issues.<br />
<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com9tag:blogger.com,1999:blog-7740886266706212134.post-55167868087999351042018-09-03T19:44:00.001-07:002018-11-04T15:19:59.596-08:00Starting pool skating in my fortiesI started teaching high school wood shop recently, and one of the woodworking projects I found I like most is making skateboard decks. This rekindled my interest in skateboarding as an adult, after not skating for over 25 years. I started again by skating the longboards I built, just cruising around on them, but it felt so good that I started thinking about doing the kind of skating that I'd always dreamed of but had been too afraid to do: pool skating. I've never skated half-pipes, and I can't do an ollie, but I decided to give it a try.<br />
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So, in July of 2016, at 45 years old, I went to the park and pushed around the bottoms of the pools, and it was every bit as enjoyable as I envisioned. I only had a longboard, which made it hard to turn tight enough for pool skating, but I had that first taste. I got some guy to show me how to drop in, and after a few tries (no hit-the-ground falls though) I was able to drop into about a four foot bowl. The next day I went to my local skate shop and bought a more traditional board, a popsicle-shaped job that could make the tight turns when carving a pool, and then went right back and dropped in again. Unfortunately, the short wheelbase of the popsicle deck had a completely different feeling, and I fell backwards and dislocated my shoulder on the first run of my second trip to the park.<br />
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<tr><td class="tr-caption" style="text-align: center;">Here I am at the hospital after an x-ray.</td></tr>
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It was maybe 9 months until I was able to sleep on my right side again, and after a year I still couldn't throw anything. After a long and frustrating year and a half I had healed enough to think about going back for my third skate session. I read a lot and learned that a longer wheelbase would help with the kind of fall I took, so I bought yet another deck made just for pool skating with a 15.5" wheelbase, and I've been pool skating with that for about four months now.<br />
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<tr><td class="tr-caption" style="text-align: center;">Eureka Springs skatepark is a chill little pool in the trees.</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">Feels like flying.</td></tr>
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The important and beautiful thing about pool skating is that it feels so good. The feeling of gravity and centrifugal forces, the weightlessness at the top of a carve, the flow and focus, it is all so much like I imagine flying would feel. I still can't get into the tiles or coping, and my frontside carves are weak, but how I look skating doesn't matter to me at all, and I wish I hadn't worried so much about how I looked back when I first wanted to do this in my teens. I healed a lot faster then. </div>
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11/4/2018 Edit: I have now built up the courage to drop in, which has enabled me to get into the tiles in my local skatepark's bowl. </div>
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Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com5tag:blogger.com,1999:blog-7740886266706212134.post-84735468356863962772018-08-16T19:15:00.002-07:002018-08-16T19:20:36.721-07:00Overview of videosHere are some links to videos of projects I've done.<br />
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Soccerbots:<br />
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Mad Eye Moody Eye:<br />
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3D printed RC car:</div>
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Stop Motion Animation:</div>
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Rubber band powered airplane:</div>
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Railroad Cart:</div>
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<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com1tag:blogger.com,1999:blog-7740886266706212134.post-29048645358871377012018-02-12T22:06:00.000-08:002018-07-27T11:49:46.298-07:00Linear classroom wall clockI teach high school computer aided drafting, engineering, digital electronics, and wood shop. One of the problems I have is that I often forget what period I'm in, and also what time it ends. I'm not all, "Where are we? Who are you people?" or anything, it just feels like third period sometimes during second period. And no matter what, I can <b>never</b> remember when the classes let out. I made an outer ring to my classroom clock showing where the minute hand will be when the period lets out, and it's pretty helpful if I can remember what period I'm in. We have a different bell schedule on Wednesdays though, with a later start, and fifth period happens before fourth period that day, so that's not helpful when trying to figure out what's going on either.<br />
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I've long dreamed about a long, linear clock that slowly travels down my 32 foot classroom wall, with the periods all blocked out, so that I can just glance at it and know what period I'm in, and how much time is left. I wanted it to automatically show the different bell schedule on Wednesdays, reset itself at the end of each day, and not run on the weekends. I wanted it to be highly (even unnecessarily) mechanical with exposed electronics, to reflect the subjects that I teach, and I wanted to build it entirely with materials and methods my students have access to in my classes.<br />
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So, finally, after four years of dreaming, one semester of brainstorming and designing, and two months of all my spare time doing actual fabrication and troubleshooting, the clock is working, although in an advanced prototyping stage.<br />
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Normally, this is where I would lay out a step by step process for building your own clock, but I'm not going to do that here. It's just too custom fitted to my wall, and if anything needed re-gearing to make it fit into your space, it would basically need a complete redesign. What I want to focus on here are the essential skills that anybody would need in order to design this, or something like it.</div>
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First up is:</div>
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<span style="font-size: large;">Conceptual Thinking</span></div>
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No question about it, this is the hardest part of a project like this. It requires the ability to visualize what you want to end up with, and in the context of the tools and skills you have available to you. One of my favorite sayings is, "To a man with a hammer, every problem looks like a nail." Conceptual thinking requires that you have a large enough skill set to solve the problem, and have an understanding of each of those skills deep enough that you can be creative with its implementation. It boils down to a vision of the final project, and a vision of the path to getting there. </div>
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For the clock, my major hangup was the motor. I was convinced the only way I was going to be able to achieve the positional accuracy of this clock was with stepper motors. I've never used stepper motors in a project, but I've been wanting to for a long time. I've read books and internet articles about them, and I feel like I have a good understanding of them. I know that they need a dual H-bridge driver and a microcontroller, at least, and that they come in several styles of winding, that one of their strengths is holding torque, and that they are power hungry. </div>
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However, I didn't want to change the battery all the time, and I don't need any holding torque at all on this project, so I suspected that they weren't the best solution in this case, but I still really wanted to use them, and I didn't know how else I would get my positional accuracy needed to get the hand to land exactly on a minute mark every time. One day I was reading an article (probably on <a href="https://hackaday.com/" target="_blank">Hackaday</a>) in which somebody was using a wheel with a hole in it to count light pulses to make a robot go an exact distance with a cheap brushed dc motor. Boom. There it was: the solution, when I wasn't even researching my clock, but just reading for enjoyment. </div>
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Every single part of this clock went something like this. How was I going to get exact second or minute pulses? (With a cheap <a href="http://www.josepino.com/circuits/index?one_second_timebase.jpc" target="_blank">hacked quartz clock movement</a>? With my microcontroller's inaccurate internal clock? From the internet with an ESP8266 wifi module? A <a href="https://www.sparkfun.com/products/12708" target="_blank">DS1307 real time clock</a>?) How would I account for the different schedule on Wednesday? What would I use for power? How would it return at the end of each day? Could I prevent it from running on the weekends? How would I paint my walls? What is the ideal microcontroller for this project?</div>
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All these questions and so many others! And every one was a hard-fought battle for the knowledge required to make it happen. Not every single thing must be known during the conceptual phase, however. You just have to know enough to know that you can figure it out when the time comes, or to at least have a couple of backup plans. I won't lie; it's hard. It's why when you post an elegant 3D printed solution to a problem on the internet <a href="https://youtu.be/p-3e0EkvIEM" target="_blank">everybody wants the .stl files</a>. It's why so many books and magazines write complete how-to articles with parts lists and completed downloadable code. If I were starting my journey towards making 3D printed, laser cut, and CNC'd projects with microcontrollers and electronics, I would read, read, and read. Blogs, books, parts supplier's parts descriptions and tutorials. Every day, for years.</div>
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This brings us to:</div>
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<span style="font-size: large;">Mechanical Design Skills</span></div>
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For me, this is the easy part. After a college minor in drafting, and 20 years of professional 3D modeling experience, I can usually breeze through the mechanical design portion of a project. I realize that this is not going to be a common experience for the new maker though, so I'm going to break down the design skills into the sub-skills of hand sketching and 3D modeling. </div>
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My computer aided drafting students HATE to hand draw their concepts before they jump on the computer and start 3D modeling their parts. They just want to get to the fun part, like they're playing an expensive game of Minecraft. Soon enough though, they realize they can't go any further because they don't have a plan, they can't visualize how their parts go together, and then it is evident that they have no idea what they are doing. </div>
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Paper drawings are the solution! I'm not saying you need to break out the T-square and triangles (although that <i>is</i> pretty fun), but some good engineering graph paper, a pencil, and a big eraser will make the design process shorter and faster in the long run. I prefer to draw my projects in full scale when possible. One of the big problems I see when trying to design things in a computer aided drafting program is that parts are often accidentally designed with features so small that they are nearly impossible to fabricate, but it is difficult to get a sense of scale in 3D software. When drawing on paper it is important to draw your objects from more than one side, so that you get a sense of depth and how the parts fit together front-to-back. </div>
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I personally think that 3D modeling skills are the number one thing you can learn to improve your maker game. 3D modeling is the Microsoft Word of the 21st century. It enables you to 3D print, or CNC cut, or laser your own designs. It helps you make plans for complicated things you are going to fabricate by hand as well. You should choose a piece of software and learn it well. If you're a student or a teacher, I would suggest Autodesk Inventor, since it's super powerful and it will be free for you. Otherwise it's insanely expensive for the hobbyist. My second choice would be Autodesk's Fusion 360. I've never used it, but it has almost all of the same capabilities as Inventor (with the glaring omission of a gear generator) and it's free. There is a huge hobbyist user base and lots of online tutorials. It can generate .stl files and g-code for CNC fabrication. There are so many other options as well, but try to choose something modern and capable that can grow with you as your skills grow. Resist the temptation to choose a piece of software just because it seems easy to use.</div>
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<span style="font-size: large;">Electrical Design Skills</span></div>
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There has never, ever, ever been a better time to learn electronics. Not only is there so much information on the internet about learning electronics, but newer, cheaper, more powerful, and easier to use components are being released constantly. Companies like Adafruit, Sparkfun, and Pololu are taking tiny, hard-to-solder chips and building easy-to-use breakout boards with them. Microcontrollers and microprocessors programmable in dozens of popular languages, including graphical block-based languages like Scratch and Blockly. The biggest problem quickly becomes choosing a platform to base your designs around. </div>
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If I were just beginning my journey into electronics, I would start by purchasing two books: <a href="https://www.amazon.com/Make-Electronics-Learning-Through-Discovery/dp/1680450263/ref=asap_bc?ie=UTF8" target="_blank">Make: Electronics</a> and <a href="https://www.amazon.com/Practical-Electronics-Inventors-Fourth-Scherz/dp/1259587541/ref=asap_bc?ie=UTF8" target="_blank">Practical Electronics for Inventors</a>. I'm also a huge fan of <a href="https://www.amazon.com/There-Are-Electrons-Electronics-Earthlings/dp/0962781592/ref=asap_bc?ie=UTF8" target="_blank">There Are No Electrons: Electronics for Earthlings</a> and <a href="https://www.amazon.com/Robot-Builders-Bonanza-Gordon-McComb/dp/0071750363" target="_blank">Robot Builder's Bonanza</a>. </div>
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I would make it a high priority to learn how to solder and etch circuit boards using the toner transfer method. I would choose a chip microcontroller (like an AVR or Picaxe) rather than a board microcontroller (like an Arduino or Micro:bit), preferably in a language you already know (I only know Basic, so I use the Picaxe microcontroller). This suits my style of projects, which are small, fairly simple, mechanical, and inexpensive. </div>
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<span style="font-size: large;">Fabrication Skills</span></div>
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I hesitated to include fabrication skills on my list here, because so much of what we can build today is built digitally, with lasers and 3D printers and CNC equipment. If all goes well, humans shouldn't have to touch the parts too much on small projects like these. I did drill out all of the holes on my gears so that I would have a perfectly round, more precise hole, and that required a small drill press. The gears rotate on axles made of 3mm threaded rod and 4mm OD brass tubing, and those needed to be cut with a small hand saw. On many of my projects I <a href="http://lcamtuf.coredump.cx/gcnc/" target="_blank">cast urethane rubber parts with silicone molds</a>. At any rate, you should not hesitate to purchase a tool and learn to use it. It's probably going to cost the same amount of money when you buy it later, and you will have all of the time between now and then improving your skills with that tool. </div>
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<span style="font-size: large;">Persistence and Troubleshooting</span></div>
This is a tough one. Let me assure you that nothing is ever going to go right on the first try if you are pushing yourself to build and design more amazing things all the time. On this clock, it turns out that infrared light shines right through my 3D printed plastic in the Z axis, so the clock never knew it had traveled one rotation of the minute wheel. It took a week to figure out that it was a mechanical problem and not a problem with my IR emitter or detector, or the code that interfaces with them. The motor driver I chose, the SN754410, draws 25mA all the time, even just sitting there overnight, apparently, and that's enough to drain my 1000mAh battery in just one day. Not cool. I had to switch to a DRV8838, which is more efficient, but required rewiring all of the motor driver circuit and making major modifications to the microcontroller program. The acrylic I made the base plate out of is starting to crack from it's laser cut edges, apparently from an incorrect power setting I used on my laser. I still need to figure out what caused that and exactly what I'm going to do to prevent it. It never ends.<br />
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The internet is such a great resource in the aid of troubleshooting. I had my <a href="http://www.picaxeforum.co.uk/showthread.php?30387-Hardware-interrupt-confusion&highlight=brian" target="_blank">questions answered</a> over on the Picaxe forums when I couldn't go any further on my own. Almost any problem you have, somebody has probably faced it before as well. Sometimes it's best to sit a project aside for a few days to roll it around in your subconscious when things seem impossible. It's important to remember when starting a project that it's going to be hard almost all the way through it, and just get mentally ready for it. I find that documenting my projects online (like this) is a great way to keep my motivation up. I think about how cool some person in some place I've never even heard of is going to think it is.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com4tag:blogger.com,1999:blog-7740886266706212134.post-70544233622265100282018-01-13T14:33:00.001-08:002018-01-26T18:04:04.353-08:00Making gears for 3D printing using Autodesk Inventor<div class="separator" style="clear: both; text-align: center;">
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You want to design your own thing that you're going to 3D print, and it's going to have gears. Awesome! It's probably going to be something great. Being able to design gears for 3D printing is a super useful skill, but if you don't know anything about gears it could be a little more complicated than you might expect. I'm going to tell you what I know about gears, and how to design them for use in your 3D printed project using Autodesk Inventor.<br />
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I can hear what you're thinking right now: "What?!? Inventor?!? Do you think I'm made of money?!? Why don't you show me how to make gears in Fusion 360?" Let me tell you I would LOVE to show you how to make involute gears in Fusion, but I don't know how. I've done some cursory research, and no other software makes generating custom involute gears as easy as Inventor, free or expensive. Also, Inventor is free for students and teachers, so hopefully you fall into one of those categories, or at least can convince Autodesk that you do.<br />
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First, lets get the vocabulary out of the way. There is a ton of gear vocabulary, but I'm only going to discuss the minimum that we need to know to make the gears.<br />
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Pitch Diameter: This is the diameter of your gears if the gear teeth were infinitely small. In other words, if your gears were perfect cylinders with perfect friction on each other, the diameter of these cylinders would be the pitch diameter. When designing gears from scratch, without the help of a $1,890 (per year!) piece of software, the pitch diameter is our most important dimension. In Inventor though, it won't be that important to know.<br />
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Center Distance: Half of the pitch diameter of the first gear plus half of the pitch diameter of the second gear would give you the distance from the center of one gear to the other. If you have two shafts, and you want to connect them with gears, the center distance is how far apart those shafts will be.<br />
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Outside Diameter: This is the diameter of the circle that makes up the tops of the teeth. It isn't important in any of our calculations, but it is important if our gears are going to fit into a housing.<br />
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Pinion: This is the name of the smaller of two mating gears. The other one is just called the gear.<br />
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Diametral Pitch: This describes the size of the teeth. The units are generally teeth per inch of pitch diameter. The bigger this number is the smaller the teeth are. Must be a whole number. Common pitch sizes in radio controlled cars are 32, 48, and 64. Both mating gears must have the same pitch.<br />
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Module: This does the same thing as diametral pitch, which is to describe the size of the teeth, but with metric units and as a ratio. It is the number of millimeters of pitch diameter divided by the number of teeth. LEGO Technic gears have a module of 1. So, the LEGO 24 tooth gear has a pitch diameter of 24mm. <i>I almost always design my gears with module instead of diaetral pitch, even though I design everything else in inches. I have learned that the smallest consistently trouble-free teeth that I can 3D print are a module of 1. </i><br />
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Backlash: This is how much a gear can rotate when the other gear is being held still. If there is no backlash there will be excessive friction. Backlash is important in 3D printed gears, because it is difficult to control if the parts are slightly oversized or undersized. <i>My 3D printer almost always makes my gear teeth just a hair too big, and I compensate by adjusting my backlash.</i><br />
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Involute: An involute shape is a part of a spiral. Why is this important? Because the sides of the teeth are actually not flat, like you might imagine, but rather curved in an involute shape. This is a difficult shape to manually draw in a computer aided drafting program, but Inventor will take care of this for us.<br />
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<a href="https://upload.wikimedia.org/wikipedia/commons/8/88/Animated_involute_of_circle.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="454" data-original-width="454" height="320" src="https://upload.wikimedia.org/wikipedia/commons/8/88/Animated_involute_of_circle.gif" width="320" /></a></div>
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It's not obvious, but if the sides of the teeth were flat, they would CLACK against each other when their faces met, and the tips of the faces would drag across the mating faces, causing excessive friction. The beautiful thing about the involute shape as a tooth surface is that it causes the mating teeth faces to "roll" on each other instead of sliding. This is absolutely critical in an actual working gear for mostly silent, nearly friction free operation.</div>
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<a href="https://upload.wikimedia.org/wikipedia/commons/c/c2/Involute_wheel.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="256" data-original-width="256" src="https://upload.wikimedia.org/wikipedia/commons/c/c2/Involute_wheel.gif" /></a></div>
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Pressure Angle: This describes the angle that the teeth surfaces press against each other at. There are two common options, 14.5 and 20. I have always used 20°. Mating gears should have the same pressure angle.</div>
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Helix Angle: Some gear teeth are not parallel to the axis of rotation, but rather wrap around the gear diameter at an angle, sort of like a slight spiral.</div>
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<a href="https://upload.wikimedia.org/wikipedia/commons/e/ed/Anim_engrenages_helicoidaux.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="457" data-original-width="539" height="271" src="https://upload.wikimedia.org/wikipedia/commons/e/ed/Anim_engrenages_helicoidaux.gif" width="320" /></a></div>
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The benefit of this is that it causes much less noise and friction. Almost all automotive gears are helical these days, except for the reverse gear in manual transmissions, which is straight cut, and is why your gears sound like they are "whining" in reverse. The drawback is that the gears want to "unscrew" from each other, which makes them push in opposite directions along their axis of rotation. This makes it so that you need thrust bearings to keep them in place. In 3D printed applications this is generally impractical. It is possible to put two opposite-angled helical gears together to form a single gear, which is called a herringbone gear. </div>
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<a href="https://upload.wikimedia.org/wikipedia/commons/0/0f/Herringbone_gears_(Bentley%2C_Sketches_of_Engine_and_Machine_Details).jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="401" data-original-width="374" height="320" src="https://upload.wikimedia.org/wikipedia/commons/0/0f/Herringbone_gears_(Bentley%2C_Sketches_of_Engine_and_Machine_Details).jpg" width="298" /></a></div>
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It has all of the benefits of a helical gear but none of the drawbacks. They are very difficult and expensive to machine, but just as easy to 3D print as any other kind. They have the additional benefit of keeping the gears aligned with each other, which can often be used to simplify other parts of the gear train design.</div>
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On to Inventor!<br />
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You might assume that you would design two gears as separate
parts and then put them together in an assembly file, because that’s the way
everything else is done in Inventor, but you would be wrong. Gears designed in Inventor’s gear generator
tool are designed in an assembly file, and the part files are generated
automatically. So, the first thing we
need to do is make a new assembly file, and then save it.<o:p></o:p><br />
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Next, we will go to the Design tab, and click on the Spur
Gear generator button. You may see that there
are also options for generating bevel gears and worm gears, but neither of
these options are able to generate functioning 3D printable parts. They are for representing parts that they
assume you are going to purchase. The
spur gear generator is the same way, but at the end there is a trick for
turning them in to useful parts.<o:p></o:p><br />
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Once the window pops up, make sure you click on all three
window expanders: the one to the right of the main area, the one below the main
area (but above the Calculate/OK/Cancel buttons), and the one to the right of
the Cancel button.<o:p></o:p><br />
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Now we have to make some decisions. <o:p></o:p></div>
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1) Do you want to use diametral pitch or module? Like I said earlier, I make all of my gears
using the module system of tooth sizing.
I am very happy with a module of 1mm for 3D printing. Click the radio button under Size Type to
make your choice.<o:p></o:p></div>
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2) Do you want to tell Inventor how many teeth each gear
needs to have, or simply what the gear ratio is? I like to specify the number of teeth because
when I’m designing my gears, I don’t usually have the parts that hold the gear
shafts designed yet, and I can put them wherever they want. Because I know my tooth size module (usually
1mm for me) and the number of teeth, that is how I control my center distance
later. This plan may not work for you,
but that’s what I do. Make this choice
with the Input Type radio buttons.<o:p></o:p></div>
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You need to make choices 1 and 2 before you go on to make
choice 3.<o:p></o:p></div>
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3) Inventor is going to end up calculating SOMETHING for
you. What do you want it to be? Your choices are under the Design Guide
dropdown. I nearly always make my choice
as Center Distance. This means I say
what my module is, how many teeth each of my gears have, and Inventor uses
these two inputs to calculate my center distance. If I don’t like the center distance that it
calculates for me, I change the number of teeth on my gears until it’s what I
want. I have found this to be by far the
easiest method of designing gears, but it requires that I don’t have a center
distance that is fixed. <o:p></o:p></div>
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If you have a center distance that must absolutely be held,
you can chose one of the other options and let Inventor calculate what your
module, tooth count, or module AND tooth count is. There is another option for Total Unit
Correction, but I don’t know what that does, and I’ve never used it. In fact, any time there’s a box for Unit
Corrections anywhere in this process, I leave it alone. <o:p></o:p></div>
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Once your big three choices have been made, you should go
ahead and change your pressure angle to 20 or 14.5 degrees (I’ve always used
20), and change your Helix Angle to zero, even if you are going to actually
make a 3D printable helix gear. (We’ll
do the helix part later with the coil command, if that’s what you’re into.)<o:p></o:p><br />
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Make sure you unclick the Internal checkbox, unless you want
internal gears. Inventor can make them,
and they work, but I have found them to be finicky with regard to their
smoothness and center distance.<o:p></o:p><br />
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You can set your Facewidth of both Gear1 and Gear2 to be
however thick you want them.<o:p></o:p><br />
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Next, enter how many teeth you want on Gear1 and on
Gear2. Make Gear1 be the smaller number
if the two gears do not have the same number of teeth. In other words, make Gear1 be the
pinion. This will help you keep track
of things later.<o:p></o:p><br />
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Ignore the Cylindrical Face and Start Plane buttons. Inventor can design gears into an assembly in
which you have already defined the gear axis and face planes, but I’ve never
done that. It seems complicated.<o:p></o:p><br />
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At this point you should be able to hit the Calculate button,
and the Inventor calculated fields will update.
I have never in my life had Inventor think that my gears were going to
work. It always says, in red text,
“Calculation indicates design failure!”
Yet, they always seem to work just fine.
There is probably a way to dig deep into Inventor and fix this, but it’s
the easiest to just ignore it. <o:p></o:p><br />
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After that you can hit the OK button, and Inventor will open
up a window allowing you to rename the gear files (but I just keep the default
names Inventor gives them), then another giving you that same warning again;
just hit Accept. At this point you will
place the two gears, as an assembly, into your assembly file. If you zoom in to the meshed teeth, you will
see that these teeth are interfering with each other, and that they have a very
simplified face profile. THESE GEARS ARE
FOR VISUAL REPRESENTATION ONLY! Involute
teeth are very complicated, and if Inventor went and put in a bunch of
mathematically complex parts into moving assemblies, it would bog down
computers badly when they were rotated.
Furthermore, it’s a pretty safe assumption that most people are buying
their gears from a gear supplier, and it’s a waste of processing power to
needlessly over-complicate them here. <o:p></o:p><br />
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We do need them with a true involute profile though, so what
you are going to do is to right-click on one of the two gears, and choose
Export tooth shape. A window will pop up
asking you if you want to export the tooth shape of the pinion or the gear, and
what kind and how much backlash you want.
I normally leave it at Normal, and I make the backlash as big as I can (before Inventor changes the field text to red, meaning it won't work),
which is often about .006”. I think my
3D printer over-extrudes, so I need my teeth to be thinner than they should be,
and even with my biggest backlash sometimes my teeth mesh too tight and I have
to adjust the center distance in my assembly that holds the gear axles. <o:p></o:p><br />
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<a href="https://3.bp.blogspot.com/--QSPLJVPo5I/WlqGYVcFx9I/AAAAAAAAAQc/hwkcYt6AgK4ri_QfQ307fLmpMDfVJeJhwCLcBGAs/s1600/ExportToothWindow.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="567" data-original-width="467" height="320" src="https://3.bp.blogspot.com/--QSPLJVPo5I/WlqGYVcFx9I/AAAAAAAAAQc/hwkcYt6AgK4ri_QfQ307fLmpMDfVJeJhwCLcBGAs/s320/ExportToothWindow.JPG" width="263" /></a></div>
<br /></div>
<div class="MsoNormal">
Once you have done that, click OK, and Inventor will open
you a new part, which is a cylinder with a sketch, not of the tooth, but of the
space between two teeth.<br />
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<a href="https://4.bp.blogspot.com/-vpv6JL6mWxk/WlqGt9T63VI/AAAAAAAAAQo/E8i-ZRCdBi8WMX50TB5zizIxrPO1ggUuQCEwYBhgL/s1600/ToothSketch.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="697" data-original-width="795" height="280" src="https://4.bp.blogspot.com/-vpv6JL6mWxk/WlqGt9T63VI/AAAAAAAAAQo/E8i-ZRCdBi8WMX50TB5zizIxrPO1ggUuQCEwYBhgL/s320/ToothSketch.JPG" width="320" /></a></div>
<br />
What you need
to do is make that area a cutting extrusion, all the way through.<br />
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<br />
After you have done that, you need to make a
circular pattern of that feature, and array it the number of teeth that are on
that gear.<br />
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<a href="https://1.bp.blogspot.com/-jz2GNnYOPAM/WlqGt_NHT8I/AAAAAAAAAQk/R_wb4tzpR6Me4Vjx3_wddNx-9G2KsESzQCEwYBhgL/s1600/CircularPattern.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="701" data-original-width="996" height="225" src="https://1.bp.blogspot.com/-jz2GNnYOPAM/WlqGt_NHT8I/AAAAAAAAAQk/R_wb4tzpR6Me4Vjx3_wddNx-9G2KsESzQCEwYBhgL/s320/CircularPattern.JPG" width="320" /></a></div>
<br />
Technically you have a working
3D printable gear now, but really you need to draw a hole in the middle of it
and extrude it through so that it can either slip fit onto an axle, or press
fit onto an axle. <o:p></o:p></div>
<div class="MsoNormal">
<br />
Tips and tricks:<o:p></o:p></div>
<br />
<div class="MsoNormal">
If you want to design a compound gear (a single part with two different gears stuck together side by side) for 3D printing, the best way to do it is to make two different involute toothed gear part files, then stick them together in an assembly, and make an .stl file out of the assembly.<o:p></o:p><br />
<br />
If you want to make herringbone gears, make your facewidth half as big as you really want it to be, and instead of using the extrude command to cut your space between the tooth, use the coil command to cut it into a spiral. Make sure you spiral both Gear1 and Gear2 the same angle. Make the circular pattern of the spiral tooth space. Then make a derived part of Gear1, making it a mirror of the original part. Finally, make an assembly of the gear and the mirrored derived gear, and there's your herringbone gear.<br />
<br />
It is extremely unlikely that you are going to be able to use the center distance that Inventor calculates for you as your true center distance in the real world with 3D printed gears. I ALWAYS make my gear shafts adjustable so that I can fine tune the real-life center distance for optimum gear engagement. <br />
<br />
If you want to make bevel gears with a true involute tooth shape, <a href="http://brianzawesomeblog.blogspot.com/2016/01/creating-involute-bevel-gears-in.html" target="_blank">check out my blog post</a> on how to do that.<br />
<br />
Useful Links:<br />
<a href="https://engineerdog.com/2017/01/07/a-practical-guide-to-fdm-3d-printing-gears/">https://engineerdog.com/2017/01/07/a-practical-guide-to-fdm-3d-printing-gears/</a><br />
<br /></div>
<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com9tag:blogger.com,1999:blog-7740886266706212134.post-59217448689629924922017-11-11T22:16:00.000-08:002017-11-11T23:31:56.673-08:00Building a Canoe PaddleAside from building things, my main recreational activity is canoeing. I paddle mostly on rivers that are shallow and rocky, so I split a lot of paddles. I typically buy the <a href="https://bendingbranches.com/canoe-paddles/recreational/loon/straight" target="_blank">Bending Branches Loon</a> model. It's cheapish and light, feels good in my hands, and I can buy them locally. I really wanted to make my own paddle though, so that's what I did. I teach high school wood shop, and one of the great benefits is that I have a really awesome wood shop all to myself in the summer.<br />
<br />
The first thing I did was to watch the How it's Made video on canoe paddles. It turns out this is Grey Owl's facility, and I think they are making the Voyageur in this video. I mostly did it the way they do it, with some adjustments to suit my tool availability.<br />
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<br />
<br />
I also watched this video from Sanborn Canoe Co. I mostly <i>didn't</i> do what they do, but I really like the way their paddles turn out, and I would like to incorporate more of their techniques in my future builds.<br />
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<br />
<br />
First, I glued up the blade halves. This looks like it's going to end up as a single glued piece of wood, but there's no glue between the two middle pieces of walnut. For my blade I used walnut closest to the shaft, then cherry, then some more walnut, then maple on the outsides for impact resistance. My paddles get beat up on the sides of the blade the worst.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/--tLwIAiBPd8/Wge_rrsZdLI/AAAAAAAAANM/I4ZQ0eIUcHQpo3ha3yQr2F1r8vuIWvFwwCLcBGAs/s1600/IMG_0218.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/--tLwIAiBPd8/Wge_rrsZdLI/AAAAAAAAANM/I4ZQ0eIUcHQpo3ha3yQr2F1r8vuIWvFwwCLcBGAs/s320/IMG_0218.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Gluing the blade halves</td></tr>
</tbody></table>
While that was drying, I glued the shaft. It is made of basswood for light weight and stability, with a walnut stringer down the middle. The 1/16" walnut sliver was the hardest part of the entire woodworking project. At the time I didn't have a drum sander, so I had to cut it perfectly on the table saw. I really dislike cutting thin things on the table saw (and the only piece of walnut that I had at the time was warped enough that planing it flat would have made it nearly non-existent). Now that I have a drum sander I would have cut this piece on the band saw and sanded it flat, but it worked out OK anyway. I glued it all against the table to keep it straight.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-ZshW4VvIU6I/Wge_ru25ODI/AAAAAAAAANI/uHrD6__FdZY4COhT0rSWr_M4yW-OhZHHwCLcBGAs/s1600/IMG_0219.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-ZshW4VvIU6I/Wge_ru25ODI/AAAAAAAAANI/uHrD6__FdZY4COhT0rSWr_M4yW-OhZHHwCLcBGAs/s320/IMG_0219.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Gluing the shaft</td></tr>
</tbody></table>
After a few hours I glued it all together, including a few pieces for the handle. I intentionally left the handle long on the blade end for two reasons. The first is that my thickness planer snipes badly, and I wanted it to snipe that leftover part instead of the blade. The second will become apparent when we get to the CNC shaping of the blade.<br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-2mU4MWHMH1o/Wge_rvv90qI/AAAAAAAAANE/bnJO8z_XBsw_L7G2qE0fpGXBljolR0c0ACLcBGAs/s1600/IMG_0222.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-2mU4MWHMH1o/Wge_rvv90qI/AAAAAAAAANE/bnJO8z_XBsw_L7G2qE0fpGXBljolR0c0ACLcBGAs/s320/IMG_0222.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Gluing it all together</td></tr>
</tbody></table>
I made sure the handle matched the wood on the blade.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-klHvWFIMtYY/Wge_uhL6n-I/AAAAAAAAANQ/CNX_tIkuacUu9SbiQ5X-bKjYAYQf0iLYgCLcBGAs/s1600/IMG_0224.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-klHvWFIMtYY/Wge_uhL6n-I/AAAAAAAAANQ/CNX_tIkuacUu9SbiQ5X-bKjYAYQf0iLYgCLcBGAs/s320/IMG_0224.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Future handle</td></tr>
</tbody></table>
After it dried for a few hours I ran it through the planer, taking off only what I needed to get it flat.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-tUNPqDGx9MQ/Wge_wQsCQZI/AAAAAAAAANY/_Ya-XIuD4U8Ca5h8PRbYTEDl4LnsPq3zwCLcBGAs/s1600/IMG_0228.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-tUNPqDGx9MQ/Wge_wQsCQZI/AAAAAAAAANY/_Ya-XIuD4U8Ca5h8PRbYTEDl4LnsPq3zwCLcBGAs/s320/IMG_0228.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Thickness planer action</td></tr>
</tbody></table>
At this point I got really excited. If I had to do it again, I would have used single pieces of cherry on the blade instead of the two pieces glued together, or put a maple sliver between the pieces. Not a giant deal, but next time.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-UlrKtaDIO6w/Wge_wcShhtI/AAAAAAAAANU/XxjFeQEQLPMeMksapU1cb_6J50onCHHMgCLcBGAs/s1600/IMG_0230.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-UlrKtaDIO6w/Wge_wcShhtI/AAAAAAAAANU/XxjFeQEQLPMeMksapU1cb_6J50onCHHMgCLcBGAs/s320/IMG_0230.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Looking good</td></tr>
</tbody></table>
Here's the handle.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-VXsiHjiD2yU/Wge_x-mX1eI/AAAAAAAAANc/8p5zZpsXcIw8cZj0S_6za3GrLziQQUmRgCLcBGAs/s1600/IMG_0231.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-VXsiHjiD2yU/Wge_x-mX1eI/AAAAAAAAANc/8p5zZpsXcIw8cZj0S_6za3GrLziQQUmRgCLcBGAs/s320/IMG_0231.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Handle</td></tr>
</tbody></table>
The next step was to cut the profile, but I didn't cut the end of the blade. This is for when I shape the blade on the CNC, after I flip it over it will still lay flat. Pictures below. Note that the shaft is thinner than the shaft glue-up. It is 1" wide, and I planed the whole thing to 1.25" thick, to match the handle of the Bending Branches Loon that I currently use and like.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-yYm85ypAoco/Wge_1AV-1LI/AAAAAAAAANk/8FAbJsIe9MAYBrdicHsgiEcjDbYeaunZwCLcBGAs/s1600/IMG_0233.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-yYm85ypAoco/Wge_1AV-1LI/AAAAAAAAANk/8FAbJsIe9MAYBrdicHsgiEcjDbYeaunZwCLcBGAs/s320/IMG_0233.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Mostly cut out on the bandsaw</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-b_a6Ssx4O-k/Wge_0LZh0qI/AAAAAAAAANg/HRm4d5aBvwYZUksK5UXfvG-JK84i48g3QCLcBGAs/s1600/IMG_0234.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-b_a6Ssx4O-k/Wge_0LZh0qI/AAAAAAAAANg/HRm4d5aBvwYZUksK5UXfvG-JK84i48g3QCLcBGAs/s320/IMG_0234.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Cutting straight lines on the shaft was hard for me</td></tr>
</tbody></table>
Next I routered the whole thing, both sides, with a half inch round-over bit This was mostly to shape the shaft and handle, and to provide a neat transition between the shape of the shaft and the upcoming blade taper. I wish I had a quarter-oval bit that would make the shaft oval instead of a rectangle with rounded corners, but I've never seen one. I could use a custom shaper blade like in the How It's Made video, but it's probably not worth it at this point. I would <i>really</i> love to hand shape the shaft with drawkinves and spokeshaves, but while I have both of these tools, I'm not yet adept enough at sharpening the blades to make them work well.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-VwQ3pNtEBks/Wge_2UBFWsI/AAAAAAAAANo/hpLiPE6PKvoVWGaF5w2L1HunnuEaZ1-qgCLcBGAs/s1600/IMG_0236.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-VwQ3pNtEBks/Wge_2UBFWsI/AAAAAAAAANo/hpLiPE6PKvoVWGaF5w2L1HunnuEaZ1-qgCLcBGAs/s320/IMG_0236.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Beginnings of a nice shape to the walnut piece</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-_gny_Q9DrL8/Wge_4Rnw6hI/AAAAAAAAANs/ETqnTcaxCD84sgVdIlDGldWcxvfyLtqkACLcBGAs/s1600/IMG_0237.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-_gny_Q9DrL8/Wge_4Rnw6hI/AAAAAAAAANs/ETqnTcaxCD84sgVdIlDGldWcxvfyLtqkACLcBGAs/s320/IMG_0237.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Basswood burns badly when routering its endgrain, apparently</td></tr>
</tbody></table>
Before I was a wood shop teacher I was a drafter, and I teach some computer aided drafting classes too. I used these skills to model my paddle blade in Autodesk Inventor, then use the (awesome) Inventor HSM to make the g-code to shape the taper of the paddle. I would like to make the taper a more complex shape and add a small spine with the shaft transition, but I decided to keep it shaped like the Loon that I know works well for me. I have read that a spine can cause flutter if not shaped correctly, but mostly I'm lazy and I just wanted to get this done.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-GDVK1ocBlPE/Wge_5wvNZ-I/AAAAAAAAANw/g_Aj9TUZt-kvPsIl0WzxkrFlgXF4_KnjQCLcBGAs/s1600/IMG_0242.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-GDVK1ocBlPE/Wge_5wvNZ-I/AAAAAAAAANw/g_Aj9TUZt-kvPsIl0WzxkrFlgXF4_KnjQCLcBGAs/s320/IMG_0242.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">On the CNC!</td></tr>
</tbody></table>
Here is a shot that shows the main reason I kept the blade too long. If I hadn't, when I flipped it over to cut the other side it would have been difficult to hold to the table. If I didn't have a CNC, I would have cut it on a bandsaw, on its side. I doubt I would have been able to do as good of a job as the robot though. Again, someday I hope to be able to hand shape all of this with planes, chisels, and spokeshaves. They say, "To a man with a hammer, every problem looks like a nail." My hammer is my CNC.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-SktC0JWWQ7I/Wge_6T8ZGzI/AAAAAAAAAN0/pyJ5zyZyVlEDpoRXbMFN9kXgFOSVViDdACLcBGAs/s1600/IMG_0244.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-SktC0JWWQ7I/Wge_6T8ZGzI/AAAAAAAAAN0/pyJ5zyZyVlEDpoRXbMFN9kXgFOSVViDdACLcBGAs/s320/IMG_0244.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Still with the leftover on</td></tr>
</tbody></table>
At this point it looked like a paddle, and I was very excited. There was a LOT of sanding to do, and I was envious of the folks in the How It's Made video's giant belt sanders.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-eO7ktbX2wj0/Wge_8wK9zlI/AAAAAAAAAN4/fo8PVUvsRRQ-Fo45Kf90xXpQTp3ng4Z3ACLcBGAs/s1600/IMG_0246.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-eO7ktbX2wj0/Wge_8wK9zlI/AAAAAAAAAN4/fo8PVUvsRRQ-Fo45Kf90xXpQTp3ng4Z3ACLcBGAs/s320/IMG_0246.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Looks like a paddle!</td></tr>
</tbody></table>
I was very excited about the way the wood joints curved, and spent a lot of time making sure the transition between the shaft's 1/2" router shape and the blade taper looked good.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-dc_tt3P6jY0/Wge_-O-TlsI/AAAAAAAAAN8/6LN3RUQd7Sgzk2toQbdFJivQDmE3j8tbQCLcBGAs/s1600/IMG_0247.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-dc_tt3P6jY0/Wge_-O-TlsI/AAAAAAAAAN8/6LN3RUQd7Sgzk2toQbdFJivQDmE3j8tbQCLcBGAs/s320/IMG_0247.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Walnut brings out a nice shape</td></tr>
</tbody></table>
I have a 2" diameter oscillating spindle sander that I used to shape the finger and palm part of the handle. I think it turned out particularly nice. I was very happy that I spent the time to get that sliver of walnut down the center cut and glued in the handle. It brings out the shape nicely.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-ve2Z4nvB7Vg/Wge_-udYvII/AAAAAAAAAOA/MVEs8w0869cJjpB7eaJuGVUuvBOQvSokgCLcBGAs/s1600/IMG_0249.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-ve2Z4nvB7Vg/Wge_-udYvII/AAAAAAAAAOA/MVEs8w0869cJjpB7eaJuGVUuvBOQvSokgCLcBGAs/s320/IMG_0249.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The handle</td></tr>
</tbody></table>
My next step was to give it some tip protection. I beat the daylight out of the blade tips of my paddles, and if I had left this paddle as is, it would split and dent, especially where the soft basswood is exposed in the middle. I decided to make an ash tip guard, and I wanted it to be connected with a tenon and lots of glue surface. It took a long time to plan, but I decided on a two-part tip with a two-step glue-up. Here is the first half of the tip after being cut on the CNC.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-BqkuNmy3Plw/WgfABSXo1oI/AAAAAAAAAOE/Ty0ci8zz-zsb72fNcAioFPkaPR0PzmwLgCLcBGAs/s1600/IMG_0523.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-BqkuNmy3Plw/WgfABSXo1oI/AAAAAAAAAOE/Ty0ci8zz-zsb72fNcAioFPkaPR0PzmwLgCLcBGAs/s320/IMG_0523.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Half of the ash tip guard</td></tr>
</tbody></table>
Then I cut the mating profile onto the blade. The walnut strip down the middle made positioning the bit in the middle of the blade much easier when I started the program.<br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-wv5GHiX0WKg/WgfACaBu5QI/AAAAAAAAAOI/5A7EmYKQTUQOVkm2REzjnagIU8unG4a6ACLcBGAs/s1600/IMG_0525.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-wv5GHiX0WKg/WgfACaBu5QI/AAAAAAAAAOI/5A7EmYKQTUQOVkm2REzjnagIU8unG4a6ACLcBGAs/s320/IMG_0525.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Cutting half the tenon</td></tr>
</tbody></table>
Next I glued the two pieces together. They are being clamped up and down, and also along the length of the shaft. I built a clamping point out of 2x4s to pull against.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-0keErV69efM/WgfACvcl20I/AAAAAAAAAOM/-EQtlGMGEMUKIbpSZQEHX2LiJR-5BQ-kQCLcBGAs/s1600/IMG_0527.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-0keErV69efM/WgfACvcl20I/AAAAAAAAAOM/-EQtlGMGEMUKIbpSZQEHX2LiJR-5BQ-kQCLcBGAs/s320/IMG_0527.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Will the gluing never end?</td></tr>
</tbody></table>
Then I cut the other half of the tenon on the CNC.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/--H790iFrsho/WgfAFGtJ0KI/AAAAAAAAAOQ/hO9-osvRxV4-viXTHIKeEL2h80Lv9Uv0ACLcBGAs/s1600/IMG_0535.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/--H790iFrsho/WgfAFGtJ0KI/AAAAAAAAAOQ/hO9-osvRxV4-viXTHIKeEL2h80Lv9Uv0ACLcBGAs/s320/IMG_0535.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">2nd half of the tenon</td></tr>
</tbody></table>
At this point I shaped the end of the blade to its final shape. This would help guide me in knowing where to cut the second half off at, as the tip of the blade wood would be hidden after the next gluing.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-Qy2mS_DaWlc/WgfAGa_qgKI/AAAAAAAAAOU/heCzzf5ciiIt7tabiu2HCDZ0KRmM6OekQCLcBGAs/s1600/IMG_0539.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-Qy2mS_DaWlc/WgfAGa_qgKI/AAAAAAAAAOU/heCzzf5ciiIt7tabiu2HCDZ0KRmM6OekQCLcBGAs/s320/IMG_0539.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Final blade shape</td></tr>
</tbody></table>
this is the CNC of the other half of the tip guard. Note that it does not have a step, so the two pieces of ash will not be glued along the centerline of the blade, but rather offset along one side of the tenon.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-pDrLAR6uXMc/WgfAGxcV3WI/AAAAAAAAAOY/zKz56kY7d-AtoPcWl1yaD0oCsHsQP6B7ACLcBGAs/s1600/IMG_0540.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-pDrLAR6uXMc/WgfAGxcV3WI/AAAAAAAAAOY/zKz56kY7d-AtoPcWl1yaD0oCsHsQP6B7ACLcBGAs/s320/IMG_0540.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">More tip guard wood</td></tr>
</tbody></table>
<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-eeilBkFU7nI/WgfAJORAKVI/AAAAAAAAAOc/4GyLknI4JTQWTStRnDfmIaEwzayoWVESwCLcBGAs/s1600/IMG_0541.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-eeilBkFU7nI/WgfAJORAKVI/AAAAAAAAAOc/4GyLknI4JTQWTStRnDfmIaEwzayoWVESwCLcBGAs/s320/IMG_0541.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Here's how it will fit.</td></tr>
</tbody></table>
More gluing.<br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-ccbL6kWp7SM/WgfAKnFqDYI/AAAAAAAAAOg/ROSLBUA-SzEjTW5JUXVc0ZQfSb4hC0xfACLcBGAs/s1600/IMG_0542.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-ccbL6kWp7SM/WgfAKnFqDYI/AAAAAAAAAOg/ROSLBUA-SzEjTW5JUXVc0ZQfSb4hC0xfACLcBGAs/s320/IMG_0542.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Gluing never ends</td></tr>
</tbody></table>
While I was waiting for the last of the glue to dry, I CNC cut this piece out of a 2x4. It has an elliptical profile, and I used it with sandpaper to give my shaft a more pleasing profile. It's like a poor man's shaper.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-yIhZPPfsZZM/WgfALNVAMtI/AAAAAAAAAOo/5BD6rOpAOwQRIL26ofW0s5eq0jtUN1cJwCLcBGAs/s1600/IMG_0545.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-yIhZPPfsZZM/WgfALNVAMtI/AAAAAAAAAOo/5BD6rOpAOwQRIL26ofW0s5eq0jtUN1cJwCLcBGAs/s320/IMG_0545.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Shaft elliptification</td></tr>
</tbody></table>
At this point I could hardly wait any more.<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://4.bp.blogspot.com/-Ov4Rn_T_eco/WgfANJDcn_I/AAAAAAAAAOw/E9I6IoeoijQpQHrE5Ad2Xz5_RpH0RYS0QCLcBGAs/s1600/IMG_0546.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-Ov4Rn_T_eco/WgfANJDcn_I/AAAAAAAAAOw/E9I6IoeoijQpQHrE5Ad2Xz5_RpH0RYS0QCLcBGAs/s320/IMG_0546.JPG" width="320" /></a></div>
After the glue had "dried"<br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-WaJND4AciHg/WgfAOSBa8VI/AAAAAAAAAO0/9yKI4-NNYEgR0rTpapditpPREGrVhQ50gCLcBGAs/s1600/IMG_0548.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-WaJND4AciHg/WgfAOSBa8VI/AAAAAAAAAO0/9yKI4-NNYEgR0rTpapditpPREGrVhQ50gCLcBGAs/s320/IMG_0548.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Impatient woodworking</td></tr>
</tbody></table>
Finally it was time for the big hand sander for final shaping. Things went fairly quickly.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-6kv0Z4IliMo/WgfAPDYCTHI/AAAAAAAAAO4/7hZ_JJfoDI0PDJuvmlKYdqy1-nwCPO0-gCLcBGAs/s1600/IMG_0549.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-6kv0Z4IliMo/WgfAPDYCTHI/AAAAAAAAAO4/7hZ_JJfoDI0PDJuvmlKYdqy1-nwCPO0-gCLcBGAs/s320/IMG_0549.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Belt sander ftw</td></tr>
</tbody></table>
Next time I want to make the middle lump pointy-er.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-mtgV-qDtptk/WgfARHLdFPI/AAAAAAAAAO8/N4UJmCn26S060mH-jdFrByYu4DwKK0BawCLcBGAs/s1600/IMG_0550.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-mtgV-qDtptk/WgfARHLdFPI/AAAAAAAAAO8/N4UJmCn26S060mH-jdFrByYu4DwKK0BawCLcBGAs/s320/IMG_0550.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">It ended up looking pretty good</td></tr>
</tbody></table>
<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-OsJ_VP2sDMM/WgfASJuVZTI/AAAAAAAAAPA/ldoMQ0Qx1i8lLwKpOUa_lnaUPbh98WDxwCLcBGAs/s1600/IMG_0551.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-OsJ_VP2sDMM/WgfASJuVZTI/AAAAAAAAAPA/ldoMQ0Qx1i8lLwKpOUa_lnaUPbh98WDxwCLcBGAs/s320/IMG_0551.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Nice.</td></tr>
</tbody></table>
<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-BpTam5sxV3U/WgfAS4bc8wI/AAAAAAAAAPE/PvBYsXWfOIcVMjp9Ozj1-h8fwdcEdwpfACLcBGAs/s1600/IMG_0553.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-BpTam5sxV3U/WgfAS4bc8wI/AAAAAAAAAPE/PvBYsXWfOIcVMjp9Ozj1-h8fwdcEdwpfACLcBGAs/s320/IMG_0553.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">You can't really see the glue line between the two pieces of ash</td></tr>
</tbody></table>
I needed to fiberglass the sides of the blade for strength, and I have a laser cutter, so why not cut the fiberglass on the laser? Lots of reasons, it turns out, but I didn't know them at this time. Don't do this. The edges burn ever so slightly. Not everywhere, but enough places that it took some time to cut out the burned parts with scissors, which sort of made the laser cutting pointless. That wasn't the main reason though. More below. Also, the fiberglass you buy at Lowes is 6 oz. fiberglass, which holds way too much resin and adds weight. 4 oz. would have been better, or even less.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-6r24IHn4NUA/WgfAWf7PHYI/AAAAAAAAAPI/8_TrNyytm8ooTMI4eWMMgItWE9UuuOcpwCLcBGAs/s1600/IMG_0558.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-6r24IHn4NUA/WgfAWf7PHYI/AAAAAAAAAPI/8_TrNyytm8ooTMI4eWMMgItWE9UuuOcpwCLcBGAs/s320/IMG_0558.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Laser cut fiberglass cloth.</td></tr>
</tbody></table>
Speaking of lasers, I used the engraver to burn my name and a logo into the basswood, which turned out nice. You have to trick this unit into thinking the front door is closed with magnets.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-Dcr4l11yk0o/WgfAWr4my1I/AAAAAAAAAPM/pOftfFtq834-iOsJyS3XlIgSj6vzeFSxwCLcBGAs/s1600/IMG_0563.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-Dcr4l11yk0o/WgfAWr4my1I/AAAAAAAAAPM/pOftfFtq834-iOsJyS3XlIgSj6vzeFSxwCLcBGAs/s320/IMG_0563.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">"Lasers"</td></tr>
</tbody></table>
I mostly canoe the Buffalo National River in Arkansas, and it's thanks to the hard work of Neil Compton (along with many others too) that we have this treasure. They fought for years before I was ever born to save it from being dammed. He is no longer with us, but his canoe is on display in Bentonville and <a href="https://media-cdn.tripadvisor.com/media/photo-s/03/0e/92/cb/compton-gardens-and-conference.jpg" target="_blank">it has this triangle pattern panted on it</a>. I decided to engrave it into my paddle as an homage to him.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-7SL9-rhBTRw/WgfAXO-0AEI/AAAAAAAAAPQ/APo3M7eccWUSe1sCrfIWNdmzsyPwfs-wACLcBGAs/s1600/IMG_0564.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-7SL9-rhBTRw/WgfAXO-0AEI/AAAAAAAAAPQ/APo3M7eccWUSe1sCrfIWNdmzsyPwfs-wACLcBGAs/s320/IMG_0564.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Thanks Neil!</td></tr>
</tbody></table>
Everything had gone really well, and worked on the first try, up until this point. We are now two days into fabricating this paddle, but the rest of the job would take a week and a half. I want to express at this point how much I dislike the process of fiberglassing. It's important, however, for the lifespan of the paddle. You can make the blade much thinner if you strengthen it with fiberglass, which saves weight and allows it to slice through the water easier. I decided to use epoxy resin instead of the more "normal" polyester resin because it's supposed to stick to wood better. I had used Bondo polyester resin (which I bought at Lowes) to repair a paddle once, and it worked, but indeed it delaminated from the wood in several places after time and abuse. The epoxy had almost no odor, which was great, as polyester resin smells truly awful. I used Evercoat because I was able to buy it locally, although it was a hassle finding it. Nobody stocks epoxy resin, it seems. Epoxy resin costs WAY more than polyester resin. Since completion I have been recommended to use U.S. Composites 635 thin epoxy resin, and it is much cheaper than most I have found.<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://1.bp.blogspot.com/-mwQfZ_kTSWE/WgfAY0GuuWI/AAAAAAAAAPU/X4BY_cbJxwswrlRrQBDg_1m8Pv_T624FgCLcBGAs/s1600/IMG_0568.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-mwQfZ_kTSWE/WgfAY0GuuWI/AAAAAAAAAPU/X4BY_cbJxwswrlRrQBDg_1m8Pv_T624FgCLcBGAs/s320/IMG_0568.JPG" width="320" /></a></div>
Here is what NOT to do. I put the cloth on the face of the paddle, then poured the resin over it, like I saw on a YouTube video. I should have read the comments though because after I went back when this day was over and watched it again they all said not to do this. The cloth will float on the resin, which makes a space under it full of resin which adds weight but not strength, and will make the face look lumpy and not smooth.<br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-yfy1JIKghsw/WgfAb4sgugI/AAAAAAAAAPY/-Lsux0QOYsAlY6DomMChaBUGmZiNJFaPACLcBGAs/s1600/IMG_0571.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-yfy1JIKghsw/WgfAb4sgugI/AAAAAAAAAPY/-Lsux0QOYsAlY6DomMChaBUGmZiNJFaPACLcBGAs/s320/IMG_0571.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Don't do this</td></tr>
</tbody></table>
<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-9q64hNc289k/WgfAb0oZZ8I/AAAAAAAAAPc/SP--jOH_iC4GYZkMMI3JMREJC6QK0MCzgCLcBGAs/s1600/IMG_0572.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-9q64hNc289k/WgfAb0oZZ8I/AAAAAAAAAPc/SP--jOH_iC4GYZkMMI3JMREJC6QK0MCzgCLcBGAs/s320/IMG_0572.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Ugh. Lumpy.</td></tr>
</tbody></table>
What you SHOULD do is paint down a thin coat of resin, roll the fiberglass cloth onto it to stick it down, then add a bit more resin to fill the cloth. That's what I did on the other side and it worked great. Here's the problem with the laser cut cloth though, and that's that it should have overlapped the edges so that I could have cleanly sanded them down when the epoxy hardened. Instead I got this annoying ridge all the way around, near the edges, that took a ton of time and resin to fill.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-t_trASvH4KE/WgfAc1w7EAI/AAAAAAAAAPg/XYzeDFPRDpAOHg0_FZDY8RzMZj2HmjHYQCLcBGAs/s1600/IMG_0577.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-t_trASvH4KE/WgfAc1w7EAI/AAAAAAAAAPg/XYzeDFPRDpAOHg0_FZDY8RzMZj2HmjHYQCLcBGAs/s320/IMG_0577.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Laser cut fiberglass equals misery</td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: left;">
I was also distressed to find that the epoxy resin darkened the basswood significantly. I lost a lot of the contrast in the wood that I liked, but I guess I should have expected it, as it ended up similar in tone to my current basswood paddles. I'm not sure what I'm going to do about that in the future.</div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-Ole4SOygVzY/WgfBBDYRsgI/AAAAAAAAAQA/ZvHDq1htHTwtYeXiPPKPsoWTVaCTyLA3gCLcBGAs/s1600/IMG_0587.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://4.bp.blogspot.com/-Ole4SOygVzY/WgfBBDYRsgI/AAAAAAAAAQA/ZvHDq1htHTwtYeXiPPKPsoWTVaCTyLA3gCLcBGAs/s320/IMG_0587.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">White wood is now tan wood</td></tr>
</tbody></table>
It took a lot of sanding and adding more epoxy, then sanding more before things started looking good again. Every coat took 24 hours before it could be sanded too. Ugh.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-HKZa_A8hZrQ/WgfAfaVgMaI/AAAAAAAAAPk/3CbWDJuMcFcqs36gQ-NPCH3qbNBV2ONUwCLcBGAs/s1600/IMG_0578.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://2.bp.blogspot.com/-HKZa_A8hZrQ/WgfAfaVgMaI/AAAAAAAAAPk/3CbWDJuMcFcqs36gQ-NPCH3qbNBV2ONUwCLcBGAs/s320/IMG_0578.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Before the final epoxy coats</td></tr>
</tbody></table>
I ended up having major fish-eye problems with my epoxy, and I never did figure out why. Eventually I just stopped adding coats and brushed a final coat of Minwax water based Spar Urethane over everything for UV protection. It turned out all right I guess, but it was way more work than it should have been.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-td_hh1kHDCE/WgfAhyw7X9I/AAAAAAAAAPs/h5ZEQBRbZHAEUTJWfcyRxmHVzKybiGqZACLcBGAs/s1600/IMG_0592.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://1.bp.blogspot.com/-td_hh1kHDCE/WgfAhyw7X9I/AAAAAAAAAPs/h5ZEQBRbZHAEUTJWfcyRxmHVzKybiGqZACLcBGAs/s320/IMG_0592.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Finally!</td></tr>
</tbody></table>
I didn't weigh it before the fiberglass, but it sure did feel heavier afterwards. One pound thirteen ounces isn't terrible, but it's heavier than I wanted. I could have thinned the blade more, I think, and that's where you want the weight reduced.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-mYLHwfzbBc8/WgfAiC2t5bI/AAAAAAAAAPw/XAIgL6BGYEYeAwwCMmdZnEw7JHJjbAm0QCLcBGAs/s1600/IMG_0596.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-mYLHwfzbBc8/WgfAiC2t5bI/AAAAAAAAAPw/XAIgL6BGYEYeAwwCMmdZnEw7JHJjbAm0QCLcBGAs/s320/IMG_0596.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A tad on the heavy side</td></tr>
</tbody></table>
Overall I'm happy with the way it turned out. I'm going to try to use and abuse it like a normal paddle. It's been a fairly dry late summer and fall paddling season though, so even though it's November now, I still haven't had a chance to try it out.<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://3.bp.blogspot.com/-jHmmqi8nadI/WgfAmiEg3aI/AAAAAAAAAP0/OqujZdKT244BxtCLF9GCWnGjW9O4kYKgACLcBGAs/s1600/IMG_0622.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1200" data-original-width="1600" height="240" src="https://3.bp.blogspot.com/-jHmmqi8nadI/WgfAmiEg3aI/AAAAAAAAAP0/OqujZdKT244BxtCLF9GCWnGjW9O4kYKgACLcBGAs/s320/IMG_0622.JPG" width="320" /></a></div>
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://1.bp.blogspot.com/-fM22Kqr2LWc/WgfAnKX7WYI/AAAAAAAAAP4/UCXxuifkjicpE_HQKMOvG4IrRxOx7x6jwCLcBGAs/s1600/IMG_0623.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1600" data-original-width="1200" height="320" src="https://1.bp.blogspot.com/-fM22Kqr2LWc/WgfAnKX7WYI/AAAAAAAAAP4/UCXxuifkjicpE_HQKMOvG4IrRxOx7x6jwCLcBGAs/s320/IMG_0623.JPG" width="240" /></a></div>
<br />
Since I built this one, I mostly completed another paddle, made mostly of western red cedar, but the CNC gave up in the middle and plunged a giant gouge right down the middle of my blade. Another reason to switch to hand tools? We have a new control board and everything seems to be back to normal. I have also purchased the book <a href="https://www.amazon.com/Canoe-Paddles-Complete-Guide-Making/dp/1552095258" target="_blank">Canoe Paddles: A Complete Guide to Making Your Own</a>, and I would recommend it.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com2tag:blogger.com,1999:blog-7740886266706212134.post-65239961698600341712016-01-14T19:39:00.000-08:002020-03-06T15:00:04.879-08:00Creating Involute Bevel Gears in Autodesk Inventor Using the Zweerink-Snider Process<div class="separator" style="clear: both; text-align: left;">
3/6/2020 note: There is an easier set of instructions on how to do this <a href="https://brianzawesomeblog.blogspot.com/2020/03/easier-way-to-make-involute-bevel-gears.html" target="_blank">here</a>.</div>
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<br /></div>
<div class="separator" style="clear: both; text-align: left;">
In my high school CAD II class we are 3D modeling radio
controlled cars, 3D printing the parts, and racing them. Everybody is super pumped and things are
going well, but our drivetrain options are somewhat limited. We currently use pulleys press fit to the
output shaft of our motors and rubber bands to transfer power to the rear
wheels, but rubber bands slip badly, break often, and are very inefficient,
wasting a lot of power in the form of friction.
Some students discovered Inventor’s ability to make spur gears with a
true involute tooth profile, and their results were noticeably superior to
rubber bands. We assumed that we could
use that knowledge to make involute bevel gears as well, but Inventor lacked
the “export tooth shape” feature on the bevel gear generator that made accurate spur gears possible. Inventor can generate several types of gears,
but they are all simplified for visualization purposes only, and are nearly
worthless for 3D printing or CNC machining.
Only on the spur gear generator does it have the option to export a true
involute tooth shape, which can be used to make a rapid prototyped, functional
gear. How to transfer the involute shape
of a spur gear into a bevel gear design was a problem that seemed simple at
first, but turned out to be extremely difficult to figure out. With the help of one of my students who was
also taking trigonometry, we were able to come up with a process that generates
working bevel gears using the exported tooth shape from the spur gear
generator. </div>
<div class="MsoNormal">
<o:p></o:p></div>
<div class="MsoNormal">
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-24PzybzmxKU/VphsCQPnAEI/AAAAAAAAAK0/94qBL56TQOw/s1600/IMG_0272.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="240" src="https://2.bp.blogspot.com/-24PzybzmxKU/VphsCQPnAEI/AAAAAAAAAK0/94qBL56TQOw/s320/IMG_0272.JPG" width="320" /></a></div>
</div>
<div class="MsoNormal">
Here is how we did it.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
My 3D printer is an Afinia H480, which I recommend heartily
to all teachers, and I use ABS filament for strength. I have found that the finest functional teeth
that I can reliably print have a module of 1mm.
This means that if the gear has a diameter of 24mm, it will have 24 teeth. Lego gears have a module of 1mm.<o:p></o:p><br />
<br /></div>
<div class="MsoNormal">
Open a new assembly file and save it. Open the Design tab, and click Spur
Gear. Expand all expanders, to the
right, down, and then the” <<” next to the cancel button. In the bottom section change input type to “Number
of Teeth” and size type to “Module”.
Change Design Guide to “Center Distance”. Now you can enter the number of teeth you
want on each of the two gears. A
pressure angle of 20 degrees works fine.
Keep your helix angle at 0. Set
your module to 1mm. It doesn’t matter
what your facewidth is for what we’re doing.
After you have your data entered (Module and Number of Teeth), you can
hit calculate. I’ve never had it tell me
my gears would work. It’s always
“Calculation indicates design failure!”
Ignore this. Click “OK” and
accept the failure again in a pop up box.
<o:p></o:p></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-RDjGtzWqE2I/VphiaoRwRsI/AAAAAAAAAJg/IacV6jPF7Dk/s1600/A.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="285" src="https://4.bp.blogspot.com/-RDjGtzWqE2I/VphiaoRwRsI/AAAAAAAAAJg/IacV6jPF7Dk/s320/A.jpg" width="320" /></a></div>
<div class="MsoNormal">
Now you should have a couple of gears on your screen. These gears are not ready to be used. If you zoom in you can see that they overlap
with interference. We need to right-click on one of them and choose
“Export Tooth Shape”. We will have to do
the rest of this procedure twice unless your gears have the same tooth count as
each other. Once for the pinion (the
smaller of the two gears) and once for the gear (the larger of the two
gears). Use “Normal” backlash, and
choose the largest value it will let you enter.
For 1mm module gears, it seems to be about .006”. This backlash will keep the gears from
interfering with each other with an imprecise 3D print. Click “OK”.<o:p></o:p><br />
<br /></div>
<div class="MsoNormal">
Now Inventor will take you to an .ipt part, which will be a
cylinder with one of the spaces between the teeth on a sketch on the end
surface. If you were making a spur gear
you would make a cutting extrusion of that space, then do a 3D circular array
of it in the amount of teeth you entered in the gear calculator. We, though, are going to delete the
extrusion, but leave the pinned Sketch1.
Edit that sketch, and delete all of the construction circles. Next do a 2D circular array of the tooth cut,
then trim the outer circle so that the sketch shows the actual gear profile all
the way around. Click “Finish
Sketch”. Now make a new sketch on a
plane perpendicular to that gear sketch.
I use the YZ plane. Draw a
centerline to the right, from the origin, which should be the center of the
gear. Make it pretty long. Now draw a construction line straight down,
from the origin, at least as long as the gear radius and then a little bit
more. Now draw a solid line from the
origin, down and to the right, a little bit longer than the gear radius. The angle between this line and the “down-from-the-origin”
construction line will be 90 minus the inverse tangent (aka arctan) of the gear
ratio divided by two. If I have 32 teeth
on my gear, and 8 teeth on my pinion, my gear ratio is 4. The inverse tangent of 4 is about 76. 90-76=14.
Half of 14 is 7. My angle from
vertical for that line will be 7. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://1.bp.blogspot.com/-ZNoZOGpCJX4/Vphic6LMr0I/AAAAAAAAAJo/a0DC4F8C0fM/s1600/B.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="243" src="https://1.bp.blogspot.com/-ZNoZOGpCJX4/Vphic6LMr0I/AAAAAAAAAJo/a0DC4F8C0fM/s320/B.jpg" width="320" /></a></div>
<div class="MsoNormal">
</div>
<br />
<div class="MsoNormal">
On the Windows calculator, use the “Inv” button to make tan
into inverse tan (tan^-1).<o:p></o:p></div>
<div class="MsoNormal">
Next, draw a line from the end of that line to the other end
of the centerline. Then, from that end
(end opposite of the origin) draw another line to the angled line sort of close
to the end further from the origin. Make
that line a construction line. It should
look like this:<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-UOIyFVbzZJ8/Vphic4pTQ4I/AAAAAAAAAJs/kZ9fQgyqtL4/s1600/C.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="225" src="https://4.bp.blogspot.com/-UOIyFVbzZJ8/Vphic4pTQ4I/AAAAAAAAAJs/kZ9fQgyqtL4/s320/C.jpg" width="320" /></a></div>
<div>
<br />
<div class="MsoNormal">
Next, you will place an angle dimension between the
centerline and the construction line.
This angle will be 90 minus the inverse tangent of your gear ratio,
which in this case will be 14. <o:p></o:p><br />
<br /></div>
<div class="MsoNormal">
At this point you will go back to your assembly file, right
click on the gears, and click “Edit Using Design Accelerator”. This will bring up the spur gear component
generator. Click the notepad in the
upper right corner. This will bring up a
tab in your internet browser which lists the gear parameters. We are interested in Pitch Diameter and
Outside Diameter for the gear we are working on.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-JqTr40q9gQo/Vphic7mQBkI/AAAAAAAAAJw/4_zJJgS5o9k/s1600/D.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="138" src="https://3.bp.blogspot.com/-JqTr40q9gQo/Vphic7mQBkI/AAAAAAAAAJw/4_zJJgS5o9k/s320/D.jpg" width="320" /></a></div>
<div class="MsoNormal">
Back in the sketch, place a diameter dimension from the
centerline to the lower corner of our triangle, and make the dimension the
Outside Diameter, plus .001”. The
Outside Diameter is rounded in the chart, and if our soon-to-be-revolvoed part
isn’t bigger than the gear sketch that we are going to project on it, it won’t
work, so don’t forget to add that .001”.
Now, for the lower point of the construction line, place a diameter
dimension from the centerline, and make the value the Pitch Diameter. Everything should be purple now, and the
sketch is ready to finish, so click finish sketch.<o:p></o:p></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-skqVOMabYOw/VphidUUvaLI/AAAAAAAAAJ0/ntJdU2d7rDc/s1600/E.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="186" src="https://4.bp.blogspot.com/-skqVOMabYOw/VphidUUvaLI/AAAAAAAAAJ0/ntJdU2d7rDc/s320/E.jpg" width="320" /></a></div>
<div class="MsoNormal">
</div>
<div class="MsoNormal">
<br /></div>
Next, use the revolve command to revolve the triangle along
the centerline.<o:p></o:p><br />
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-VDXp9Crj6DE/Vphidu8dZcI/AAAAAAAAAJ4/Ph3BrJZl_yI/s1600/F.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="234" src="https://3.bp.blogspot.com/-VDXp9Crj6DE/Vphidu8dZcI/AAAAAAAAAJ4/Ph3BrJZl_yI/s320/F.jpg" width="320" /></a></div>
<div class="MsoNormal">
<br /></div>
<br />
<div class="MsoNormal">
Our next step is to get a point at the far tip of the cone,
so we need to make an axis through the cone, and place a point at the place the
cone and the axis intersect. Click axis
and click the cone to make an axis, then click the down arrow next to the point
button and choose Intersection of Plane/Surface and Line. Then choose the cone and the new axis, and
there’s your point. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Next click Start 3D sketch (below Start 2D Sketch), then
click Project to Surface. The Faces is
the near side of the cone, and the Curves is the gear sketch. This will project a flat sketch onto the
curve of the near cone. The effect of
this is that the teeth are taller because they are now on the hypotenuse. Without this step the teeth would be too
short when lofted to the point at the far end of the cone. It doesn’t make as much difference on the
small gear, but on the larger gear the difference is significant. Anyway, now we use the loft command to loft
the projected 3D sketch to the point on the far cone. You will use the Cut or Intersect button in
the Loft command to make this happen. I
am not sure why, but one or the other button works, and the other one doesn’t,
but it doesn’t seem to be consistent.
Just try them both and find out which one works. At this point you have a functional bevel
gear, but not a practical one.<o:p></o:p></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-hT9qyRlmj8A/VphidogkJwI/AAAAAAAAAJ8/tI69m8ScCS4/s1600/G.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="217" src="https://3.bp.blogspot.com/-hT9qyRlmj8A/VphidogkJwI/AAAAAAAAAJ8/tI69m8ScCS4/s320/G.jpg" width="320" /></a></div>
<br />
<div class="MsoNormal">
You will need to make a plane with a sketch and a cutting
extrusion to cut your gear off at the facewidth you need. Don’t forget to use your Slice Graphics (F7)
button. <o:p></o:p></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-4-cWRJdoJSk/VphidxU330I/AAAAAAAAAKA/iEDCNiNBSn4/s1600/H.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="212" src="https://4.bp.blogspot.com/-4-cWRJdoJSk/VphidxU330I/AAAAAAAAAKA/iEDCNiNBSn4/s320/H.jpg" width="320" /></a></div>
<div class="MsoNormal">
</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Then pop a hole in the gear for your shaft.<o:p></o:p></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://1.bp.blogspot.com/-q7sY2tL1SEo/VphieExVCAI/AAAAAAAAAKI/Hn9nlE-udmQ/s1600/I.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="256" src="https://1.bp.blogspot.com/-q7sY2tL1SEo/VphieExVCAI/AAAAAAAAAKI/Hn9nlE-udmQ/s320/I.jpg" width="320" /></a></div>
<div class="MsoNormal">
</div>
<br />
<br />
<div class="MsoNormal">
The steps are exactly the same for the other gear, but you
need to remember that because the inverse tangent of 4 is 76, on the smaller
gear we used 90-76=14 for our angle. On
the other gear we will be using 76 as our angle. Why is that?
The “pitch cone” of two gears with the same number of teeth will be 45
degrees. No matter what ratio of teeth
they have, the angles of the pitch cones must add up to 90 if the shafts are at
a 90 degree angle. The angled
construction line in the revolved cone sketch was our pitch cone line.<br />
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<o:p></o:p></div>
</div>
Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com6tag:blogger.com,1999:blog-7740886266706212134.post-12392285946829853992015-08-08T21:06:00.000-07:002017-11-11T23:29:01.263-08:00Building Longboards in High School Wood Shop ClassI've been making skateboards in preparation for the upcoming year's wood shop classes that I teach. I've got my system down pretty well, and I'm going to show you how I do it. <br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-V4gcGIB0pV8/VdC2rdYaH8I/AAAAAAAAAIo/YPv3Ew7Tm5M/s1600/IMG_0310.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="300" src="https://2.bp.blogspot.com/-V4gcGIB0pV8/VdC2rdYaH8I/AAAAAAAAAIo/YPv3Ew7Tm5M/s400/IMG_0310.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Here is the final product: A horizontally laminated drop deck longboard with drop through truck mounting.</td></tr>
</tbody></table>
This blog post is going to focus on horizontally laminated longboards. You can also build vertical lamination longboards, which are like big cutting boards shaped into skateboard shapes. V-lam longboards (as they are known) are beautiful to look at, and satisfying to cruise on. I'm going to have my students build these too, but they are pretty self-explanatory. Joint wood, rip wood on table saw, glue wood together, send it through the planer, cut to final shape, router edges, drill truck holes, and apply finish. If you are currently having your students build cutting boards, you should switch to v-lam skateboard decks. There are some great write-ups in the book <a href="http://www.amazon.com/The-Handmade-Skateboard-Longboard-Cruiser/dp/1940611067" target="_blank">The Handmade Skateboard</a>, which I highly recommend. Here is a video about a guy building vertical lamination longboards:<br />
<br />
<iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/16634761" webkitallowfullscreen="" width="500"></iframe> <br />
<a href="https://vimeo.com/16634761">Waller's Rally - Catching a New Wave</a> from <a href="https://vimeo.com/user2003726">Mike Greener</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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The rest of this post will be about horizontal lamination longboards. I built a few v-lam longboards at the end of the last school year, and it was pretty easy, but I thought that the h-lam boards would be a lot harder. It turns out that the opposite is true. Horizontal lamination is like making your own plywood, and it is how the vast majority of factory-made skateboards are built. <br />
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In the DIY skateboard movement, there are two major methods for h-lam construction. The first is to use 1/16" maple veneer sheets, and to glue them together with a foam mold in a vacuum bag. There is a company called <a href="http://www.roarockit.com/" target="_blank">Roarockit</a> that sells everything you need to make that happen, and they are very involved in building skateboards in an educational environment. It is apparently very easy. The second method is to use 1/8" sheets of Baltic birch, and press them in a physical press with clamps. This is the method I will be discussing. Compared to the maple-in-the-vacuum-bag method, Baltic birch boards are a bit weaker, less resistant to chips and dings, and you can't shape 1/8" thick Baltic birch into as tight of bends as 1/16" maple.<br />
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There is one major advantage though, and that is that you can often buy Baltic birch from local lumber yards and specialty wood suppliers, while maple is only available in most places online through skateboard building suppliers. 1/8" Baltic birch is actually a 3-ply plywood, and you won't find it at a home improvement store like Lowes or Home Depot. They sell plywood there with birch outer veneers (and who knows what on the insides) in a 4 x 8 foot sheet, but you need the 5 x 5 foot sheet, not for its size, but for the birch all the way through and lack of voids in every ply. I live in Springfield, MO, and I buy mine locally from <a href="http://www.ophardwoods.com/plywoods---veneers.html" target="_blank">OP Hardwoods</a> for $25 a sheet. There is a strong possibility that the place that sells Baltic birch in your town won't have a website, so you'll need to pick up the phone book. One 5 x 5 sheet is enough to build two big 4-ply boards (four plys of three ply plywood), which may be a bit flexy if you are heavy, or almost two big 5-ply boards, which will be stiffer.<br />
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<b>Here's how I build my skateboards:</b><br />
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First, build your press. This is nothing more than a 48" x 14" piece of low grade 3/4" thick plywood with two 48" x 3" pieces glued and screwed to the bottom, 3" in from the sides. Try to make sure everything is square and flat. The pieces of wood on the top are just laying there, and are not attached. After I took this picture I drew a centerline down the middle from end to end, and also from side to side. I also made lines in 1" increments from both centerlines all the way across, and labeled them with just even numbers, starting in the middle. This way you can easily center your forms and plywood. In other words, the lines on either side of the centerline are both labeled 2", the next two are labeled 4", and so on. This way, if you have a 38" long piece of plywood that you want to center, you can place it with each end on a line that says 38" and know it is centered in the press. <br />
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I made some pieces of wood for my drops (the square ones on the ends) and for my concave (the long wedge-shaped ones). I would suggest you round the corners of your forms more than I did mine, as mine left a few indentations in the wood on the sharp corners here and there.<br />
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Next I made my pressed forms. The two end pieces hold the truck-mounting flats flat, the two center ones form my concave, and the two next-to-end pieces form my drops. You will notice that one of the two drop-forming pieces is square and the other has angles. On my first press with this form the angled one did not adequately press the edges of the Baltic birch, and there were minor gaps between my plys on that end. For the most part, 1/8" Baltic birch wants to be flat, and all of the pieces will naturally press together when you squish it all together, but you have to watch out. <br />
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Your next step will be to cut your Baltic birch into your lamination pieces. The grain orientation is important here. The sheet will bend more easily in one direction than the other. Notice that it does not bend as well in the direction that the grain is running on the outside plys (the grain is running the other way on the inside ply). Ideally you will want the outside ply grain running along the length of your skateboard. I purchased an already-cut piece of plywood at a discount for my first try, and I was unable to get all five plys to run lengthwise, so I put the single sideways grain ply in the very middle of the stack of five to minimize the effect of its easy lengthwise bending. You can cut a 60" x 60" (5' x 5') sheet into six ~10" wide x 40" long lengthwise grain pieces, and two ~10" wide x 40" long pieces with the grain running sideways. I have not done experiments to determine the perfect placement of that sideways grain piece in a 4-ply longboard, but I'm pretty sure it should be one of the two center pieces, and probably the upper one. <br />
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<i>A note about the number of plys vs. flex:</i> I used 5 plys of 3-ply 1/8" Baltic birch, with the middle ply having its grain (on the outside plys) running sideways. The centers of the truck mounting baseplates are about 32" away from each other (the wheelbase), and I have significant concave (the bending up at your heels and toes on the sides of the board, which reduces flex lengthwise). I weigh about 165 pounds, and my board has noticeable flex. Personally, I like this, as it makes the road feel smoother, but many downhillers going for speed do not like this. A layer of fiberglass on the bottom of the board is the common solution to reduce flex, but that's a whole other setup in the classroom.<br />
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Now it's time for a dry-clamping. Lots of big c-clamps are helpful here. After I built this board (and not pictured) I drilled a series of 3/8" diameter holes 1" apart all the way down both sides of the press table. Through this I put 7" tall 3/8" all-thread rod, which I attached to the table with nuts and washers. Then I drilled matching holes just a bit bigger than 3/8" in the pressed forms. Now I can use threaded rod instead of using all those c-clamps, which are needed in the other, non-skateboard-building periods while the glued deck drys. I only put the threaded rod in the holes where they are needed for the pressed form pieces. Threaded rod in every hole would make turning a wrench awkward. <br />
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You will notice that I did not get the right side drop form fully clamped down. On the wet glue clamp-up I did though. Position things so you end up with a shape you like and mark where your form pieces go. They do not need screws or glue, but some small air-nailer brads wouldn't be a bad idea. I just let mine sit there, and I did have to re-position them as I put my glued plys down, but not a big deal.<br />
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The next step is to apply glue to both sides of each piece of Baltic birch, except for the top of the top and bottom of the bottom pieces. I used a lot of Titebond III and a coarse paint roller. You could also spread it with a spreader or a stiff paintbrush. I felt like I ended up with a lot of glue in the roller when I washed it, which is somewhat wasteful, but whatever. <br />
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Now it is time for final clamping. You need to be quick here, as the glue will start to dry. I shoot for less than nine minutes between glue spread and final clamp-down.<br />
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I pulled my board out after 6 hours. Even for my first attempt, I could not believe how well everything turned out. I had some slight delamination on the edges at the bottom of the drop (as discussed earlier), but other than that it was very solid. I filled those spots with more wood glue and clamped them back down overnight.<br />
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OK, so I've got a 4 x 4 foot Shopbot CNC router in my wood shop, and I love it. By trade I'm a designer and drafter, so it plays right into my strengths. It makes life so easy at this stage of the process, which is cutting your board to shape. Now, the whole point of the wood shop class that I'm building skateboards in is to introduce students to the CNC, so this is perfect. If you don't have a CNC, now is the time to draw your longboard profile by hand, or from a pattern, or by tracing an already completed board, and cut it on the bandsaw or jigsaw. For me though, now was the time to draw my board on the computer. I used Autodesk Inventor 2015, but I would have preferred AutoCAD 2000. It is ideal for this type of work. If you have a CNC, you probably already know how to use it, but I will offer this one useful tip. Set the origin of your design to the left side of the board, right on the centerline. It is always easiest and most accurate to work from the centerline of your board as opposed to a corner. You can see in the pictures below that I marked the centerline of my board for positioning on the CNC bed. Make sure you mount your cutting bit deep enough to clear the curvy sections too. Your material thickness will be the distance from the top of the highest part of the board to the table. I cut through the air a lot before the sides got cut.<br />
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You may notice that I did not cut my truck holes at this point. The reason for that is that I hadn't chosen my trucks yet (I have since purchased Independent 169s) and I wasn't sure where my wheels would contact my board, so I may need to move those around as I decide where they go, and I'll probably drill those holes by hand. In my experience it is critical that you use a guide to drill the holes. On my first board my bits walked (even though I used a center punch) and I had to waller them out to get everything to fit right, which was just unprofessional. I now use a truck riser as my guide. If I did know what I was doing, truck-wise, you can bet I would have drilled my mounting holes on the CNC.<br />
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Here is what it looks like after sanding the surfaces and corners, and a single coat of <a href="http://www.amazon.com/gp/product/B000PRNXNY/ref=pd_lpo_sbs_dp_ss_2?pf_rd_p=1944687502&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B000BZYYH4&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0CB0RP73WEARXTCMZ6ZC" target="_blank">Minwax Polycrylic</a>. I used to use Minwax Polyurethane on my boards for the superior durability, but I have found that it yellows badly with time. I don't have any long-term observations with the polycrylic yet.<br />
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I wanted my students to be able to add some graphics, and I researched rice paper printing and water slide decal methods, but both seemed like a hassle, didn't involve any woodworking equipment objectives, and didn't seem like they were going to look that great anyway. I decided to make a Sharpie holder for my CNC so that we could draw or download some graphics and have the CNC draw them for us. <br />
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Shopbot sells an attachment for $40, but for about $2 I built this one with two 1/2" threaded PVC plugs, a 1/2" threaded PVC coupling, and some scrap plywood to hold it to the router. I put a metal 3/8" cap on top of the Sharpie to put some weight on the pen. I drilled the lower threaded plug for the diameter of the Sharpie that is normally covered by the cap (the colored plastic part) and the upper plug for the outer shaft of the Sharpie. The shoulder of the Sharpie that the cap usually contacts sits on the inside of the lower plug hole unless the holder is low enough that the tip is contacting the wood, in which case the sharpie is ready to draw. I have 0.65" of pen travel in the holder before the diameter of the pen in the lower hole becomes smaller at the tip, and this works out perfectly to accommodate the curvature of the bottom of the board.<br />
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I only drew the outline of the graphics on the CNC, so I had to color it in by hand. I'm not sure what would have happened if I had made the CNC fill it in, but it probably would have taken all day. I ended up coloring it all in with a Sharpie chisel tip. It is important to note that you must put a coat of finish on your board before you use a Sharpie, or the ink will run with the grain and make everything blurry in one direction. I will put the remainder of my poly coats on over the Sharpie.<br />
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Here is the final product, as of yet, between a finished vertical lamination board and a work-in-progress v-lam. Note that the light wood on the left polyurethaned board and the light wood on the right unfinished board is maple from the same board. I am not into that yellowing. <br />
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At this point all it needs is the grip tape and truck holes to be considered a finished deck. You can mount your deck to your trucks in a top-mount configuration (normal style) or, like I did, in a drop through mounting style. A drop through means you mount the base of your trucks to the TOP of the board, so you have to cut a square hole for the body of your baseplate to pass though, but just the body, and not the flat surface with the mounting holes. This lowers your deck by the thickness of your deck plus the thickness of your truck mounting baseplate surface. I used my CNC to cut the holes for the truck baseplate body, but hand drilled the 3/16" mounting holes using the baseplate holes as a guide.<br />
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I finished my board off with Independent 169 trucks, ABEC 11 Freeride wheels, and Bones Reds bearings. My grip tape was not quite wide enough, so I added a stylish stripe to make it wider.<br />
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I recently purchased a longboard <a href="http://www.amazon.com/YOCAHER-LONGBOARD-Skateboard-Polished-Package/dp/B007736JJ4/ref=sr_1_1?s=outdoor-recreation&ie=UTF8&qid=1439091200&sr=1-1&keywords=longboard+trucks" target="_blank">truck, wheel, and bearing combo package</a> from Amazon, and the trucks were so badly constructed that they were almost unusable. The kingpin fit very loose in the baseplate, but I have a plan to fix the kingpin in the baseplate with JB Weld to make them usable. It's tough to beat a sub $40 wheels, trucks, and bearings package on price, but that's probably what's in my student's price range.<br />
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I gathered almost everything I know from the <a href="https://www.silverfishlongboarding.com/forum/longboard-board-building-q-a-discussions/" target="_blank">Longboard Building Forum at Silverfishlongboarding.com</a>.<br />
There is a giant trove of downloadable longboard shape templates on those forums <a href="https://www.silverfishlongboarding.com/forum/churchill-manufacturing/176915-churchill-mfg-lost-longboard-templates-found-uncut-pressed-blanks.html" target="_blank">here</a>.<br />
Other common types of Baltic birch DIY longboard presses are the Toothless and the Dimm.<br />
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Edit 8/16/15: added picture of final product, notes about drop-through truck mounting, and 5 ply flex.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com18tag:blogger.com,1999:blog-7740886266706212134.post-65647697203682359302014-05-25T18:17:00.002-07:002014-05-25T18:17:54.506-07:00Adventures in BIOS Password Hacking on an IBM Thinkpad LaptopI work at a science museum as an educator, and this summer I am using a whole bunch of IBM Thinkpad T40 laptops to teach computer programming on MIT's Scratch platform. The Thinkpad laptops were left over from when we had this thing called Immersion Cinema, by Immersion Studios. They are out of business now, and since they stopped supporting their product we stopped using it, which was before I started working here. Anyway, the folks at Immersion Studios put a BIOS password on these computers, and when the little CR2032 cell dies in them you can't reset the time, because you can't enter the BIOS, and they won't run if the time is not set. UGH! Not awesome. What IS awesome though, is the internet. I used a couple of websites to learn how to scan the eeprom chip on the motherboard for the password, and after about 4 tries it worked! If you need to scan your IBM Thinkpad BIOS password eeprom, the websites I used are <a href="http://sodoityourself.com/hacking-ibm-thinkpad-bios-password/" target="_blank">here</a> and <a href="http://www.normsweb.com/tektips/thinkpad.shtml" target="_blank">here</a>. The downloaded software that is required will often show that contains a virus, but I think it is a false positive. Anyway, if you have a computer left over from Immersion Cinema that you want to use for other projects, the BIOS password is probably SUPPORT.<br />
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<tr><td class="tr-caption" style="text-align: center;">Mobile electronics workspace in use!</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">Password is SUPPORT</td></tr>
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I won't lie to you; this took me about 12 hours to do, between research on how to solve this problem, buying the parts, building a serial cable, breadboarding the circuit, and troubleshooting. I first tried to use a serial cable and just crammed wires in the end of it on the circuit side, but it turns out that some serial cables are not straight through cables. I ended up building my own with a part from Radio Shack. Also you can use Radio Shack Zener diode IN47338 aka 276-0565 diodes in place of the C5V1 diodes the above links call for. You're looking for a Zener voltage of 5.1v or so.<br />
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This is the best thing about the internet. People figuring out problems and sharing the information with the world. What did we do before the internet? We kludged things together, and badly, is what. Thank you to anybody who has ever figured something out and posted it to the internet. We need a national holiday for those people.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com5tag:blogger.com,1999:blog-7740886266706212134.post-80271217605535719672014-03-07T11:59:00.000-08:002014-03-07T12:36:51.114-08:00Mobile Electronics Workbench<div class="separator" style="clear: both; text-align: center;">
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Back in the old days I used to drag all of my electronics project parts out of the garage in boxes, set them up on the dining room table, and get to work. This worked out great until dinner time, at which point I would shove everything back into boxes and scatter it around the room until after dinner was over. There were extension cords, power strips, soldering irons, power supplies, and components. Components everywhere. It got to the point that it was more of a hassle to clean up than the projects were worth, and I sort of went on a hiatus from electronics projects. I looked around the web at solutions other people had come up with, and I decided I needed a mobile electronics workbench. A portable lab.<br />
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I wanted something with a built-in power supply, a spot for a breadboard, some soldering space that nobody would get bothered about if it got burnt spots on it, component and tool storage, a built-in extension cord, and good lighting. Here is my solution:<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/t1/541522_563430640341406_263300971_n.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="" border="0" class="spotlight" height="300" src="https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/t1/541522_563430640341406_263300971_n.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The final product</td></tr>
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<tr><td style="text-align: center;"><a href="https://scontent-b-atl.xx.fbcdn.net/hphotos-frc1/t1/486892_562948287056308_85403784_n.jpg" style="margin-left: auto; margin-right: auto;"><img alt="" border="0" class="spotlight" height="300" src="https://scontent-b-atl.xx.fbcdn.net/hphotos-frc1/t1/486892_562948287056308_85403784_n.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Light and tool hanger folded in</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">The back side, with power cord cleats</td></tr>
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I built it out of 3/8" plywood mostly, with 1/4" plywood on the back for light weight. The wood is glued together and reinforced with small nails. The tool door holds various strippers and tweezers, and folds in neatly. My eyes are not what they once were, and so I bought a magnified light on Craigslist for $30, cut it down to fit, and mounted it so that it can move up and down and still fold into the box. The dimensions of this light dictated the overall dimensions of my box, and it just barely fits, which means it fits perfectly. The front opening folds down to make a nice soldering and prototyping area. There is a little shelf for holding craft boxes of components. My light and soldering station plug into a 4-plug outlet on the inside, so I've got 2 spare plugs for other things that need AC at the table. All told it weighs about 35 pounds with everything in it. Not too bad. It has helped me complete many more projects, both big and small, than I would have without it. I can just bust out a project, fold it up for dinner, and pull it back out after the kids have gone to bed. Easy.<br />
<br />
Awesome as it is, I have some future upgrades planned for it. I would love a little vise to hold my circuit boards while I work on them. Currently I am using an old Dell ATX power supply, and it makes a high pitch hum that bothers everybody in my house. A good cheap lab supply would be ideal, especially if it was smaller too. I have had this in service for a year now, and space on the inside is valuable. I use the <a href="https://www.sparkfun.com/products/10707" target="_blank">Sparkfun soldering station</a>, which I absolutely love, but the iron holder is horrible. I would like to build my own iron holder into my mobile bench, especially since I have to take the iron out of the stock holder to get everything to fit inside after the doors are folded up.<br />
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Overall it has been great. Now I just need to find a way to store my etching supplies, my laminator, my electric skillet, and my oscilloscope in there. I guess they'll stay in the garage on an as-needed basis for now.<br />
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Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com13tag:blogger.com,1999:blog-7740886266706212134.post-91149799954122787722014-01-08T11:22:00.001-08:002014-02-03T13:43:39.317-08:00LEGO 2.4 GHz Power Functions Radio Control DIY Circuit<!--[if gte mso 9]><xml>
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</xml><![endif]-->Update: The H Bridge chip this circuit uses has a voltage drop that makes devices that use it operate more slowly than they should. An updated version 2 is in the works that uses the DRV8833.<br />
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<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">When
LEGO came out with the infrared controlled Power Functions system I was super
excited.<span style="mso-spacerun: yes;"> </span>I have dreamed of being able to
build remote controlled LEGO cars and racing them with my friends since I was a
little kid.<span style="mso-spacerun: yes;"> </span>The actual system left a lot
to be desired though.<span style="mso-spacerun: yes;"> </span>If you want a
nimble car, you have to use the LEGO 8885 infrared transmitter, but it only
offers full speed forward and reverse, and if you are using it for steering it
gives full left or right.<span style="mso-spacerun: yes;"> </span>There is no
proportional control.<span style="mso-spacerun: yes;"> </span>You can’t go at
half speed or steer just a little to the left.<span style="mso-spacerun: yes;">
</span>You can use the other LEGO transmitter, the 8879, which gives you seven
incremental speeds forward and reverse, or seven positions on the servo for
steering.<span style="mso-spacerun: yes;"> </span>That sounds perfect, but in
reality it will only send a few commands per second, and if you try to give it
more commands per second than that it will ignore them.<span style="mso-spacerun: yes;"> </span>This means that it can take 3-5 seconds to
steer from a full left to a full right, and your transmitter dial will be out
of whack with where you expect it to be when you try to go straight again.<span style="mso-spacerun: yes;"> </span>Suboptimal for sure.</span></div>
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<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">I
love the options the variety of Power Functions motors provide, but the control
system needs improvement, so that is what I decided to do.<span style="mso-spacerun: yes;"> </span>I am documenting it here so you can do it
too.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<b><span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Overview:</span></b></div>
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<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">My
circuit uses a cheap 2.4 GHz radio transmitter to quickly control two Power
Functions devices.<span style="mso-spacerun: yes;"> </span>You can control two
motors, or two servos, or one motor and one servo.<span style="mso-spacerun: yes;"> </span>The 2.4 GHz receiver sends out servo control
signals that are typically used to position a hobby servo or control an electronic
speed controller.<span style="mso-spacerun: yes;"> </span>Our LEGO motors and
servos cannot use this signal though, so we are going to use a programmable
microcontroller to translate the hobby servo signals into a pulsing signal that
can be used to power our LEGO motors and servos.<span style="mso-spacerun: yes;"> </span>The microcontroller we are going to use is
the Picaxe 14M2.<span style="mso-spacerun: yes;"> </span>I chose this
microcontroller because it is small, cheap ($4), is easy to program in the
BASIC programming language, and the only thing you need to buy to program it is
a $6 cable if you have a serial port on your computer.<span style="mso-spacerun: yes;"> </span>If you don’t have a serial port, you will
need a USB programming cable, which is more expensive, at $26.<span style="mso-spacerun: yes;"> </span>The Picaxe chip can’t output enough power to
power our motors and servos, so we are going to feed the Picaxe output signals
into an H-bridge motor driver chip, the SN754410.<span style="mso-spacerun: yes;"> </span>I chose it because it is easy to use, tough,
and cheap, at less than $3.<span style="mso-spacerun: yes;"> </span>It can
supply 1 amp of power to two different motors, which is enough for most Power
Function situations, but I have not tested it with a L or XL motor yet.<span style="mso-spacerun: yes;"> </span>I think it will handle the L motor ok, but I
know the stall current of the XL is closer to 2 amps, and that’s way too much
for the SN754410.<span style="mso-spacerun: yes;"> </span>The SN754410 does have
overcurrent protection though, so it will shut down before it does any damage
to itself.<span style="mso-spacerun: yes;"> </span>You can stack two SN754410s
on top of each other, and solder their legs together to double the power it can
handle, so if you are planning on running an XL hard, you should consider
that.<span style="mso-spacerun: yes;"> </span>The other part of the circuit is
the 7805 5 volt voltage regulator, which takes the 9 volts from the battery
pack and converts it to 5 volts, which is required to power the 2.4 GHz
receiver, the Picaxe, and the logic functions of the SN754410.<span style="mso-spacerun: yes;"> </span>The SN754410 also needs the full 9 volts to
power the motors. For the record, I am not using any external protection diodes on the SN754410, with no ill effects. There is some debate about this on the internet.</span></div>
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<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Here's a video of the results:</span></div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/gS5uMJKC1e0?feature=player_embedded' frameborder='0'></iframe> </div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
And of the first road test:</div>
<div class="separator" style="clear: both; text-align: center;">
<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/pAqWWyODG1Q?feature=player_embedded' frameborder='0'></iframe></div>
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<div class="MsoNormal">
<b><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">Functional Concept: </span></span></b></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">The concept here is that the radio controlled receiver <a href="http://www.pololu.com/blog/17/servo-control-interface-in-detail" target="_blank">sends out a pulse</a> of somewhere between 1 and 2 milliseconds every 20 milliseconds on
each of the two channels we are using. 1 millisecond tells a servo to go
full left, 2 milliseconds tells the servo to go full right, and 1.5
milliseconds tells the servo to go to its center position. We are using
the Picaxe PULSIN command to measure the length of that signal on each of the
two receiver pins. We then have the Picaxe perform some math on that data
to end up with an output signal that we send to the SN754410. <a href="http://www.pyroelectro.com/tutorials/sn754410_dual_motor_control/theory.html" target="_blank">Here is a link</a> to a great page on what the
pulse width modulation signal looks like coming out of the Picaxe and into the
SN754410.</span></span></div>
<div class="MsoNormal">
<br /></div>
<span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">
</span></span><br />
<div class="MsoNormal">
<span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">If we have a servo signal less than 1.5ms, then we need to
send out a PWM signal to the SN754410 on its 1A pin, while sending out a constant
0v signal to its 2A pin. As the servo
signal becomes closer to 1ms, we need to increase the “on” time of the PWM
signal to 1A. If the servo signal
becomes larger than 1.5ms, then we need to send 0v to the 1A pin, and start
sending a PWM signal to 2A. The math I used
to do this is in my Picaxe code. I made
sure that there was a dead zone around 1.5ms so that the motors are sure to be
stopped, and I also made sure with my code that the output signal could not be
such that my PWM signal has a larger than 100% duty cycle. </span></span></div>
<br />
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<b><span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Here
is what you will need to buy:</span></b></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">HobbyKing
HK-GT2B 3CH 2.4GHz Transmitter and Receiver<span style="mso-tab-count: 1;"> </span>$23<span style="mso-tab-count: 1;"> </span>Hobbyking.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">For
$23 you can’t beat that deal.<span style="mso-spacerun: yes;"> </span>If you
already have a transmitter, you can use any receiver that works with your transmitter, but the pins may not
match what I have on the etched board.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">14M2
Picaxe chip<span style="mso-tab-count: 2;"> </span><span style="mso-tab-count: 1;"> </span>$4<span style="mso-tab-count: 2;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Picaxe
Serial Programming Cable<span style="mso-tab-count: 1;"> </span>$6<span style="mso-tab-count: 1;"> </span><span style="mso-tab-count: 1;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">SN754410
H-Bridge Motor Driver<span style="mso-tab-count: 1;"> </span>$2.35<span style="mso-tab-count: 2;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">7805
5v Voltage Regulator<span style="mso-tab-count: 2;"> </span>$1.25<span style="mso-tab-count: 2;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">0.1
uF Capacitors (qty. 2)<span style="mso-tab-count: 2;"> </span>$0.25
ea.<span style="mso-tab-count: 1;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Female
Header<span style="mso-tab-count: 4;"> </span>$1.50<span style="mso-tab-count: 2;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">3.5mm
audio jack<span style="mso-tab-count: 3;"> </span>$1.50<span style="mso-tab-count: 2;"> </span>Sparkfun.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">This
is to connect the programming cable to a solderless breadboard to program your
Picaxe.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Two 10k
ohm and one 22k ohm resistors</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">You
can buy these at Radio Shack in 5 packs, or in a big assortment.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Copper
Clad and etchant</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">I
love Electronic Goldmine’s scissor-cut copper clad.<span style="mso-spacerun: yes;"> </span>Easy to drill and cut, and nearly clear, but you can use Radio Shack's too. We only need single sided, so grind off the unused side if your copper clad is stiff.<span style="mso-spacerun: yes;"> </span>I use Radio Shack PCB Etchant to etch my
printed circuit boards.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">LEGO
Power Functions extension wire (qty. 2) short 8886<span style="mso-tab-count: 1;"> </span>$3<span style="mso-tab-count: 1;"> </span>Lego.com</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Harbor
Freight has an assortment of tiny drill bits that I use to drill my PCB
holes.<span style="mso-spacerun: yes;"> </span>I use the 0.8mm bit for most of
my components, and just a bit bigger for the voltage regulator.<span style="mso-spacerun: yes;"> </span>I file down the legs of the voltage regulator
so they are nearly as skinny as the other components, so it sits flush against
the PCB.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">I’m
going to assume you have some electronics, PCB etching, and soldering
experience.<span style="mso-spacerun: yes;"> </span>If not, here are some links
to get you the background you need to get started on this project:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Toner
Transfer PCB building:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><a href="http://mad-science.wonderhowto.com/how-to/diy-lab-equipment-etch-your-own-circuit-boards-using-laser-printer-0134931/">http://mad-science.wonderhowto.com/how-to/diy-lab-equipment-etch-your-own-circuit-boards-using-laser-printer-0134931/</a></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">I
don’t use tape, but rather fold the paper over and push the copper clad into
the crease.<span style="mso-spacerun: yes;"> </span>Also, I have found that
ironing for 3 or 4 minutes works well.<span style="mso-spacerun: yes;">
</span>Don’t forget to rough up the surface and wash the board before you iron
on the toner.<span style="mso-spacerun: yes;"> </span>Sharpies work well for
touching up before you etch.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Through
Hole Soldering:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><a href="https://learn.sparkfun.com/tutorials/how-to-solder---through-hole-soldering">https://learn.sparkfun.com/tutorials/how-to-solder---through-hole-soldering</a></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">I
absolutely LOVE my Sparkfun 937b soldering iron (part number TOL-10707).<span style="mso-spacerun: yes;"> </span>My joints have improved drastically since I moved
up from cheap irons.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Everything
you could want to know about Picaxe:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><a href="http://www.picaxe.com/">http://www.picaxe.com/</a></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><a href="http://www.picaxeforum.co.uk/forum.php">http://www.picaxeforum.co.uk/forum.php</a></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Here are some pictures of the process:</span></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-p51C9s5Lkhk/Us2kH7wr9zI/AAAAAAAAADc/xa2mAlgYBHc/s1600/breadboard.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-p51C9s5Lkhk/Us2kH7wr9zI/AAAAAAAAADc/xa2mAlgYBHc/s1600/breadboard.jpg" height="240" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Prototyping. Note the HobbyKing receiver not yet de-cased. Is that the top of a free-with-any-purchase Harbor Freight multimeter?</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-nK469ERWj9U/Us2kY3DJNNI/AAAAAAAAADo/lwtJQUAmWyY/s1600/awesomeEtch.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-nK469ERWj9U/Us2kY3DJNNI/AAAAAAAAADo/lwtJQUAmWyY/s1600/awesomeEtch.jpg" height="320" width="240" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">This is the best toner transfer etch I've ever done. This is the first board I used AutoCAD to do my art. For my previous PCBs I used Microsoft Paint, which works, but is not awesome. </td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/--MuhnxQV-9g/Us2kIU3traI/AAAAAAAAADk/XmhZQLSFzco/s1600/soldered.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://4.bp.blogspot.com/--MuhnxQV-9g/Us2kIU3traI/AAAAAAAAADk/XmhZQLSFzco/s1600/soldered.jpg" height="240" width="320" /></a></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-vzd579N3wHo/Us2kITYi6dI/AAAAAAAAADg/XhfYdyxAom4/s1600/finalCircuit.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-vzd579N3wHo/Us2kITYi6dI/AAAAAAAAADg/XhfYdyxAom4/s1600/finalCircuit.jpg" height="240" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The HobbyKing receiver just plugs right into that socket I built out of 3 four pin headers side by side.</td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-tbw3jhCVF_w/Us2kHkDV6PI/AAAAAAAAADY/2V0qfpR4GKc/s1600/complete.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://4.bp.blogspot.com/-tbw3jhCVF_w/Us2kHkDV6PI/AAAAAAAAADY/2V0qfpR4GKc/s1600/complete.jpg" height="240" width="320" /></a></div>
<br />
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
</div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Here
is the BASIC code that you need to program the Picaxe chip with.<span style="mso-spacerun: yes;"> </span></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
bforward = B.2<span style="mso-tab-count: 2;"> </span>;the pin that
outputs not 0 when motor B goes forward</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
breverse = B.4<span style="mso-tab-count: 2;"> </span>;the pin that
outputs not 0 when motor B goes reverse</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
aforward = C.2<span style="mso-tab-count: 2;"> </span>;the pin that
outputs not 0 when motor A goes forward</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
areverse = C.0<span style="mso-tab-count: 2;"> </span>;the pin that
outputs not 0 when motor A goes reverse</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
cha = C.4<span style="mso-tab-count: 2;"> </span>;the pin
that receives the channel A pulsin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
chb = C.3<span style="mso-tab-count: 2;"> </span>;the pin
that receives the channel B pulsin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
chainput = w0<span style="mso-tab-count: 2;"> </span>;variable
that channel A pulsin uses</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
arevout = w2<span style="mso-tab-count: 2;"> </span>;variable
that gets output to motor A when in reverse (areverse pin)</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
aforout = w3<span style="mso-tab-count: 2;"> </span>;variable
that gets output to motor A when in forward (aforward pin)</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
chbinput = w4<span style="mso-tab-count: 2;"> </span>;variable that
channel B pulsin uses</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
brevout = w6<span style="mso-tab-count: 2;"> </span>;variable
that gets output to motor B when in reverse (breverse pin)</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">symbol
bforout = w7<span style="mso-tab-count: 2;"> </span>;variable
that gets output to motor B when in forward (bforward pin)</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">output
bforward<span style="mso-tab-count: 3;"> </span>;make
pin bforward an output pin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">output
breverse<span style="mso-tab-count: 3;"> </span>;make pin
breverse an output pin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">output
aforward<span style="mso-tab-count: 3;"> </span>;make pin
aforward an output pin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">output
areverse<span style="mso-tab-count: 3;"> </span>;make pin
areverse an output pin</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Main:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">let
aforout = 0<span style="mso-tab-count: 3;"> </span>;set
these variables to 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">let
arevout = 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">let
bforout = 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">let
brevout = 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmout
aforward,249,aforout<span style="mso-tab-count: 1;"> </span>;all 4 pins start
at 0v all the time</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmout
areverse,249,arevout</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmout
bforward,249,bforout</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmout
breverse,249,brevout</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Amain:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pulsin
cha,1,chainput<span style="mso-tab-count: 2;"> </span>;check the
length of the pulse coming from channel A</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
chainput < 102 then let chainput = 102 endif<span style="mso-tab-count: 1;"> </span>;you
don’t want this less than 102 ever</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">w1 =
chainput-102*22<span style="mso-tab-count: 4;"> </span>;intermediate
math</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
w1 > 1000 then<span style="mso-tab-count: 4;"> </span>;this
all checks to see if it should be forward or reverse</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">arevout
= 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">else </span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">arevout
= 1000-w1</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
chainput < 152 then</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">aforout
= 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">else</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">aforout
= chainput-152*22</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
arevout > 1000 then let arevout = 1000 endif<span style="mso-tab-count: 1;"> </span>;this
makes sure that it doesn’t get more than 100%</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
aforout > 1000 then let aforout = 1000 endif<span style="mso-tab-count: 1;"> </span>;duty
cycle which locks things up at full throttle</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmduty
areverse,arevout<span style="mso-tab-count: 2;"> </span>;output
the reverse pwm signal for motor A</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmduty
aforward,aforout<span style="mso-tab-count: 2;"> </span>;output
the forward pwm signal for motor A</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Bmain:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pulsin
chb,1,chbinput<span style="mso-tab-count: 2;"> </span><span style="mso-tab-count: 1;"> </span>;this is pretty much the same thing
as Amain but for B motor</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
chbinput < 102 then let chbinput = 102 endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">w5 =
chbinput-102*22</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
w5 > 1000 then</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">brevout
= 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">else </span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">brevout
= 1000-w5</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
chbinput < 152 then</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">bforout
= 0</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">else</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">bforout
= chbinput-152*22</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
brevout > 1000 then let brevout = 1000 endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">if
bforout > 1000 then let bforout = 1000 endif</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmduty
breverse,brevout</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">pwmduty
bforward,bforout</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">sertxd
("chA",#chainput," AF",#aforout,"
AR",#arevout," chB",#chbinput,"
BF",#bforout," BR",#brevout,13,10)<span style="mso-spacerun: yes;"> </span>;for tuning on the computer screen</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">goto
Amain</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">You can copy and past all of the above into the free Picaxe programming editor, then upload it to the chip. Read the Picaxe manual #1 to get an idea of how to do it.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">Below is a link to the pdf of the etch artwork. You will use this to print with a laser printer onto thinish glossy paper, then iron it onto your blank copper clad. I also have several component placement guides on that page. I put 4 copies of the art on one page so you can have 4 tries with a single print. Sometimes it takes that many. Also, save this file and print it with your own pdf viewer. The whiteish lines you see on the black areas are ok on your screen, but not on your paper. Google Doc's print puts the lines on the print, but Acrobat reader does not seem to.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><a href="https://drive.google.com/file/d/0B84nhek6YaVfVVMycWI4SDBkbGs/edit?usp=sharing" target="_blank">LEGO Radio Control etch art</a></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-DLywPHc1Nb4/Us2kb1dE0WI/AAAAAAAAAD0/_CV5TSKp-U0/s1600/LegoRC-Model.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-DLywPHc1Nb4/Us2kb1dE0WI/AAAAAAAAAD0/_CV5TSKp-U0/s1600/LegoRC-Model.jpg" height="320" width="302" /></a></div>
<br />
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">The Future:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">What does the future hold? I have a few upgrades planned, and here they are:</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">1) I'm going to find a smaller voltage regulator, as that is currently the tallest part. Replacing it with a shorter one will enable this whole thing to be under two bricks tall. Currently I have to use 3. Also, as long as I'm replacing the voltage regulator, I'm going to find a low-drop-out one to replace it with so my batteries can go even lower before replacing them. EDIT: I cut the heat sink of the regulator off through the middle of the hole, and now it fits in a 2 brick high space, with no ill effects. Also, my batteries will get so low that they will only barely drive the motors before the dropout voltage comes into play.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">2) I want to make a 6 channel board, since a 6 channel HobbyKing transmitter and receiver is hardly any more money than the 3 channel I'm using now.</span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">3) I would love to make an 11.1v battery pack out of hobby lithium batteries. Smaller, lighter, cheaper, more powerful than alkaline. </span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">4) Maybe someday I will gut a servo motor and replace the 7 increments with a true resistor strip circuit like every other hobby servo on the planet, and have full proportional steering. Why didn't LEGO do this in the first place? EDIT: In practice the 7 segments feel very much like full proportional steering on a LEGO car. I'm not going to worry about modifying their servos for this anymore.</span><br />
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">5) I want to build this circuit again with surface mount components. I can buy a SMT voltage regulator, capacitors, and resistors easily. The Picaxe 14M2 is offered in a hand-solderable SMT package (but shipped from the UK). <b>Now all I need to find is a hand-solderable SMT version of the SN754410 motor driver chip.</b> The ship LEGO uses on the new V2 of the infrared receiver is the TI </span><span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;">
DRV8833 but it is difficult to solder (and etch a board for) and the maximum voltage is 10.8v, and I eventually want to use a 3S LiPo at 11.1v. </span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<span style="font-family: "Arial","sans-serif"; font-size: 10.0pt; line-height: 115%;"><br /></span></div>
Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com22tag:blogger.com,1999:blog-7740886266706212134.post-65000260851445746822013-09-05T08:36:00.003-07:002013-09-05T08:36:47.072-07:00It was back in the day on the old TI-99/4A that I programmed my last video game. I learned skills that are still useful today by doing that, mostly the BASIC programming language, which I use to program the Picaxe programmable microcontrollers. It also taught me how to think about programming in general, as well as helping me think through problems. Good stuff. <br />
<br />
Recently I started using MIT's Scratch program to make video games, and let me tell you, it's awesome. I have introduced my eight year old son to it, and through it he's learning about the coordinate system, and/or decisions, velocity, variables, nesting mathematical functions, and so much more, all on top of learning to program a computer. He loves it, and that's good, because they made the software just for kids.<br />
<br />
Imagine writing a computer program by dragging commands into your script area, and the commands are shaped like puzzle pieces so that they only fit where they belong, and you've got scratch. It's awesome, and I suggest you check it out right now. I was able to write my first program in 15 minutes.<br />
<br />
<a href="http://scratch.mit.edu/">http://scratch.mit.edu/</a><br />
<br />Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com1tag:blogger.com,1999:blog-7740886266706212134.post-26636263200710576742012-07-27T09:31:00.002-07:002012-07-27T09:32:24.524-07:00Science!<br />
<div class="MsoNormal">
I teach 3<sup>rd</sup> through 5<sup>th</sup> grade science lessons
and one of my favorite new lessons has been teaching force, motion, energy, and
the scientific method with 2 liter water bottle rockets. It is a somewhat involved lesson in which we
try to determine how much water in the bottle will make it fly the
highest. The rockets are a 2 liter
bottle with a ring fin, a Nerf football nosecone, and a quick-release
nozzle. I built a Gardena style launcher
that attaches to a garden hose and a bicycle pump in which you can fill the
bottle with a predetermined amount of water (measuring with graduations marked
on the launcher guide posts). We pressurize
the bottles with 60 psi of water each launch, but vary the amount of water in
0.2 liter increments. </div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-k5etcEpFbdc/UBLBSRIZUHI/AAAAAAAAABQ/PQ97sH3RKSs/s1600/IMG_5377.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://4.bp.blogspot.com/-k5etcEpFbdc/UBLBSRIZUHI/AAAAAAAAABQ/PQ97sH3RKSs/s320/IMG_5377.JPG" width="240" /></a></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
After we have
launched and timed our rockets with 0.2 through 1.8 liter volumes of water, we
plot the time aloft on the Y axis and the volume of water on the X axis of a
graph for easy and visual data analysis.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Here is a link to the water rocket and launcher
instructions: </div>
<div class="MsoNormal">
<a href="http://www.aircommandrockets.com/construction.htm">http://www.aircommandrockets.com/construction.htm</a></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The forces acting on the rocket are the acceleration of the
water through the nozzle towards the ground, gravity, and wind
resistance/friction. The potential
energy is the compressed air in the volume of the bottle not taken up by the
water. The less water you have the more
energy in compressed air you can store, and your rocket will be lighter at
launch, but air does not have as much force to propel the rocket, as its mass
is so much less. Force = mass X
acceleration, so if what you are accelerating out the nozzle does not have much
mass, the launch thrust force will be reduced.
In other words, it’s a balancing act, and the fun part of this
experiment is to find the perfect balance of water and compressed air.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Here is where the story gets interesting. I taught this lesson for the first time about
a month ago in my first summer session, and I expected this nice dome shaped
graph, where 0.2 and 1.8 liters had the shortest time in the air, and at some
point in the middle there would be a peak.
We launched 2 rockets at each volume, and indeed my expectations were
correct, with the exception of the 0.6 liter launches. There seemed to be a dip there on both
launches. I disregarded it and assumed
that I had not put enough air pressure in the rockets for those launches. One student had measured a time that was
greater than the other students, so I made that dot really big on the graph,
and put my X on the graph where my intuition said it should be. In reality you can see the data points for
the two launches clustered in two groups of three dots well below the point at
which I placed my X. With that data
analysis, we concluded that 0.6 liters is the amount to put into your rocket to
make it fly the highest.</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-wUECgBPZrQs/UBLBiTL0qCI/AAAAAAAAABY/PW9abQw_3qo/s1600/IMAG0187.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://3.bp.blogspot.com/-wUECgBPZrQs/UBLBiTL0qCI/AAAAAAAAABY/PW9abQw_3qo/s320/IMAG0187.jpg" width="191" /></a></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Fast forward to my second summer session last week, in which
we did the same rocket experiment. In
that class we came up with very similar data, and as I was plotting it on the
graph for the class I was thinking in my head that I must have not put enough
air pressure in the 0.6 liter launch when I remembered the data from the first
session. This time I respected the data,
and plotted it as it was recorded, and you can see very clearly the 0.6 liter
dip. We even plotted the data points for both launches for 0.6 liters on this graph. This time we concluded that 0.8 liters
is the amount to use to make the rocket go the highest.</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://1.bp.blogspot.com/-ZaAJefP45FA/UBLBtduBKNI/AAAAAAAAABg/0MPjUzhdifQ/s1600/20120727_091120.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://1.bp.blogspot.com/-ZaAJefP45FA/UBLBtduBKNI/AAAAAAAAABg/0MPjUzhdifQ/s320/20120727_091120.jpg" width="240" /></a></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Now the question is WHY?
That just doesn’t make sense to me.
I am going to run this experiment on my own with 0.1 liter graduations
and very accurate measurements and see if more accurate measurements give me
more insight. My initial thought is that
there is a longer coast after thrust due to a higher initial velocity involved
at around 0.4 liters or so, but I am going to have to research this.</div>
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The takeaway lesson here is what Paul Simon told us years
ago, “A man hears what he wants to hear and disregards the rest.” There is no place for this in science, although
for 3<sup>rd</sup> through 5<sup>th</sup> graders it really did make the lesson
a lot easier to understand. This type of
thing happens occasionally even in the higher levels of science, but my job as
a science teacher is to teach kids to only trust the data, and to disregard our
preconceptions of what the outcome should be. I am glad I caught this in the second session,
and I will work this concept into my rocket lesson in the future. Science is awesome!</div>Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com2tag:blogger.com,1999:blog-7740886266706212134.post-2749741703471485032012-03-23T11:19:00.000-07:002012-03-23T11:19:43.947-07:00A lot of things that are awesome are awesome at something very specific, and today's post is that kind of post. The Dagger Dimension tandem whitewater canoe is awesome at class II+ and III whitewater. It is infuriating at anything less, like on the class I Buffalo River. With all that rocker it looks like a banana and it will not go in a straight line, but in whitewater it is a dream. Super fast turns and rock solid stability are it's strengths. It has high sides so not much water is getting in, and it is skinny, so it's easy to get strong strokes close to the centerline of the boat. Jenny and I paddled it tandem on the Hailstone (upper Buffalo River) recently, and it glided through a full day of II and III like the bottom was coated in warm butter. Awesome!<br />
<br />
<div class="separator" style="clear: both; text-align: center;"><a href="http://1.bp.blogspot.com/-aQsAPg3hUPA/T2y-IgKLfFI/AAAAAAAAABE/9_FkWN8L-ag/s1600/IMG_4606.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://1.bp.blogspot.com/-aQsAPg3hUPA/T2y-IgKLfFI/AAAAAAAAABE/9_FkWN8L-ag/s320/IMG_4606.JPG" width="320" /></a></div>Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com2tag:blogger.com,1999:blog-7740886266706212134.post-55117758855449723492011-12-03T20:04:00.001-08:002012-03-23T11:06:26.119-07:00Anton's Coffee ShopIf you live in Springfield, MO, you are either an Aunt Martha's Pancake House person, or an Anton's person. I've never been to Aunt Martha's, so I'm not going to do a compare and contrast piece between the two, but I can tell you that Anton's is awesome.<br />
<div class="separator" style="clear: both; text-align: center;"><a href="http://1.bp.blogspot.com/-OzqSfrZ_Ao0/TtrrNT0cz4I/AAAAAAAAAAk/dkDCDY4Ahmk/s1600/IMG_3748.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="http://1.bp.blogspot.com/-OzqSfrZ_Ao0/TtrrNT0cz4I/AAAAAAAAAAk/dkDCDY4Ahmk/s400/IMG_3748.JPG" width="400" /></a></div><br />
It's a little crowded, which is good, because the people who eat there are as awesome as you are, and they're sitting right next to you. I've shared a table with people I didn't know before there, but that's rare, and it's only on that one big table they have. You know the one. It is extremely rare that I don't know someone eating there on a weekend morning. Today I saw and talked to three people I knew. Last week it was two, but I talked to them longer. A lot longer. They were probably sick of me.<br />
This week it was Brandon, Nate, and Nick.<br />
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</div><br />
<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="http://4.bp.blogspot.com/-EnPrPLW9D50/TtrsKoGb7_I/AAAAAAAAAA8/knmfLIJ5mdg/s1600/IMG_3761.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://4.bp.blogspot.com/-EnPrPLW9D50/TtrsKoGb7_I/AAAAAAAAAA8/knmfLIJ5mdg/s320/IMG_3761.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div style="margin-left: 1em; margin-right: 1em; text-align: center;"><a href="http://4.bp.blogspot.com/-JdYIlfPwHHI/Ttrr91Oa8-I/AAAAAAAAAAs/EXjIFAQKz1Y/s1600/IMG_3764.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><a href="http://4.bp.blogspot.com/-JdYIlfPwHHI/Ttrr91Oa8-I/AAAAAAAAAAs/EXjIFAQKz1Y/s1600/IMG_3764.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://4.bp.blogspot.com/-JdYIlfPwHHI/Ttrr91Oa8-I/AAAAAAAAAAs/EXjIFAQKz1Y/s320/IMG_3764.JPG" width="320" /></a></div><br />
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</div><div class="separator" style="clear: both; text-align: left;">You can see from the pictures that it's a little cluttered, with all the menus stapled to the walls, hanging cookware, and whatnot. Also, there's no clear windows. They all have plastic stapled over them. Add in the jam packed people and you have a big fat dose of Anton's. Enclosed, cluttered, crowded. I know this doesn't really sound all that appealing, but you've got to experience it to appreciate it. It's awesome.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">The thing to eat at Anton's is the omelette. I get one with American cheese, onions, and mushrooms. Jenny gets the Jenny. They're all really, really good.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">So what else about Anton's? They only take cash, the bathrooms are really small, and sometimes you have to wait to get seated. When you do have a choice of where to sit you should choose the back wall to the left of the cuckoo clock. The temperature is the most stable there. By far the warmest seat is the one by the stained glass windows. In fact, this morning they asked us if we wanted the warm table. I've never had to sit at the table by the door.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">Edit: I went to Aunt Martha's the other day, and the building is cool, but the food is sub-optimal.</div>Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com2tag:blogger.com,1999:blog-7740886266706212134.post-32233633304447909932011-12-01T19:50:00.000-08:002011-12-01T19:50:27.626-08:00The Picaxe Microcontroller<div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">Ok, maybe you’ve heard about the Arduino. A lot of people think the Arduino is awesome. The Arduino is a programmable microcontroller with a bunch of connection terminals, the serial programming bus, an led or two, a 5v regulator, an oscillator, and whatnot all soldered to a small circuit board. This post is not about the Arduino. This post is about the Picaxe microcontroller, which is seriously awesome. I know you’re thinking, “Whoa! Wait a second! Let’s talk about the Arduino; that sounds pretty nice!” but I’m not going to do it. I’m a Picaxe guy.</span></div><div class="MsoNormal" style="text-align: center;"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;"><img src="http://dlnmh9ip6v2uc.cloudfront.net/images/products/10803-01_i_ma.jpg" /></span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">What’s a microcontroller? It’s an integrated circuit (those little pieces of black plastic with the legs you see soldered onto circuit boards) that you can connect to your computer and program to make decisions based on electrical input on some of the legs to output different electrical signals on other legs. It will continue to do what you programmed it to do even after you disconnect it from your computer, whenever it has a 5v electrical source. It remembers what you programmed it to do even after you remove the power.</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;"><br />
</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">Let’s say you want an LED to blink every time you push a button. You would hook your microcontroller to your computer, run the programming software and program it to blink the output of leg #1 every time the input on leg #2 is detected. Then you would disconnect it from your computer and solder an LED to leg #1 and a button to leg #2, hook it to 3 AAA batteries (4.5v is close enough) and POW! You got your wish about the LED and the button you’ve been dreaming about all these years. You can also make it do more complicated things, like adjust a bank of servos based on input from a 3 axis gyroscope to control some autonomous flying vehicle, or something more practical like controlling the pump and heating element in your hot tub based on a temperature sensor. </span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;"><br />
</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">So there’s like dozens of microcontrollers. Maybe hundreds or even thousands. I don’t know. Why the Picaxe? Let me tell you why:</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">1) It was designed to be used in education. You program it in the Basic programming language, which is intuitive and easy to learn. I taught myself Basic when I was in the 7<sup>th</sup> grade (on the TI 99/4A, which is also awesome) and it’s still the only programming language I know. It’s also a bare chip, unlike the Arduino, which has tons of external components soldered to it already. This means you have to learn to solder, when to use pull-up resistors, a thing or two about power supplies, and lots of other things that you really need to know to fully embrace electronics. The Arduino is practically a device, as opposed to a component.</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">2) It’s fast. The slower ones operate at 32 MHz. MEGA Hertz. It can perform 32 million tasks per second. That’s slow for a microprocessor (like in your computer, that’s doing a lot of math) but crazy fast for whatever you need a microcontroller to do. 32 MILLION!</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">3) It’s cheap. The most basic model costs $2.95 from Sparkfun (Sparkfun is also awesome). Yeah, you could blink that LED with a 555 timer IC from Radio Shack for $1.99, but seriously. What if you want your LED to blink slower? You’ve got to de- and re-solder your resistor and capacitor that sets the blink time on the 555, but you can just hook that Picaxe back up to your computer and adjust your blink rate to the millisecond. An Arduino costs $30, so that's a lot more.</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">4) It's small. It seems like most of my projects need to fit inside something small, like 1" tube, or a wooden railroad train, and the Picaxe fits just right. You can get surface mount microcontrollers that are a lot smaller, but so far I haven't needed anything that small.</span></div><div class="MsoNormal"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;"><br />
</span></div><span style="font-family: Arial, Helvetica, sans-serif; line-height: 115%;">So, is it the greatest microcontroller of all time? Probably not, but it is super easy and accessible, cheap, and very powerful.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif; line-height: 115%;"><br />
</span><br />
<span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;"><span style="line-height: 115%;">Here's the datasheet: </span><a href="http://www.picaxe.com/docs/picaxe_manual1.pdf">http://www.picaxe.com/docs/picaxe_manual1.pdf</a></span><br />
<span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif;">Here's Sparkfun's product page for the most basic model: <a href="http://www.sparkfun.com/products/10803">http://www.sparkfun.com/products/10803</a></span>Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com1tag:blogger.com,1999:blog-7740886266706212134.post-48305281709499680442011-11-30T20:43:00.000-08:002011-11-30T20:43:25.499-08:00How To Keep Your Volkswagen Alive - Greatest Repair Manual Ever!How To Keep Your Volkswagen Alive, A Manual of Step By Step Procedures for the Compleat Idiot is the greatest repair manual of all time. All manuals for all equipment everywhere should be written with as much artistry, care, understanding, enthusiasm, and love as this one is. <br />
<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="http://2.bp.blogspot.com/-S7Z5QAPgxHk/TtcE-VVhi5I/AAAAAAAAAAc/vX-5JdH8fpU/s1600/IMG_3747.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://2.bp.blogspot.com/-S7Z5QAPgxHk/TtcE-VVhi5I/AAAAAAAAAAc/vX-5JdH8fpU/s320/IMG_3747.JPG" width="240" /></a></div><br />
There are many reasons why this book is so great, and I'm going to tell you about them, saving the most important one for last.<br />
1) The art is just plain awesome. Hand drawn semi-psychedelic illustrations by Peter Aschwanden (listed as Junipero Scopulorum in my older spiral bound version) are fantastic. Check out how a CV joint works:<br />
<div class="separator" style="clear: both; text-align: center;"><a href="http://3.bp.blogspot.com/-9sUBly7i8bg/TtcEI_lG8mI/AAAAAAAAAAM/2UVst5bjhwk/s1600/IMG_3746.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://3.bp.blogspot.com/-9sUBly7i8bg/TtcEI_lG8mI/AAAAAAAAAAM/2UVst5bjhwk/s320/IMG_3746.JPG" width="320" /></a></div><br />
2) They assume you are dirt poor, which you probably were if you were driving a VW back in the day.<br />
3) They assume you don't know anything about anything, without being tedious when you already do.<br />
4) They give you solutions that are "good enough", taking the pressure of being perfect off your back, unless you really do need to be perfect on something, then they tell you.<br />
5) (This is the important one) They inspire and reinforce a connection between you and your machine that is rarely talked about. They ask you to get to know your car, to feel it and understand it's moods. Most people who live with unreliable machinery already do this out of necessity, but this book takes it to another level, and it's great.<br />
<br />
This book fits perfectly with Volkswagens, being a clickity-clank type of vehicle. It's worth buying an older VW bug, just to get to use this book. I'm not sure if this book would translate well to a new off-the-lot Honda, but if Honda supplied a book this good with a new Honda, I would buy one. No question.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com0tag:blogger.com,1999:blog-7740886266706212134.post-17617868011997064342011-11-29T19:08:00.000-08:002011-11-29T19:08:36.022-08:00Swisher Ride King Riding Mower<div class="separator" style="clear: both; text-align: left;">When I saw this mower in an older gentlemen's yard with a for sale sign on it, I knew I had to have it. It is clearly awesome. It's a tricycle, and the front wheel is the powered wheel, and it has continuous rotation so it steers exactly like a bumper car. I laugh out loud every time I mow with it, which is every chance I get. It's a Swisher Ride King, although I don't know the year. I'm guessing somewhere in the late 70s to early 80s, but it could be as early as the 60s. I really don't know.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dypXvYsghwIvK5h6fRcpG-6fMzeRuirPzGy_Cy2nJPs2xtnFZbXAlSS8wS2tiQaL4r4ekg83VER0zCppB6wlg' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: left;">Now, is it the best mower ever? Not by a long shot. The tricycle action makes it tippy, which causes scalping because the deck doesn't float. Also, I'm pretty sure the tipping is going to cause it to cut part of my foot off one of these days. The traction is poor as well, so I have to mow side to side on my hilly front yard, because it won't go up the hill without spinning the front wheel. Sideways on a hill = tippy, btw. Lastly, the quality of cut is pretty bad. My yard looks much better with my push mower, but I think I'm missing a piece of metal under the deck that contours to the blades, creating an updraft and directing the grass out the side. I'll have to make something and weld it in.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">With all that being said, it's still the most awesome mower ever. It is insanely small and maneuverable, has tons of moving parts, looks great, and most importantly it's an absolute blast to mow with.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">Here's a link to the owner's manual:</div><div class="separator" style="clear: both; text-align: left;"><a href="http://www.swisherinc.com/manuals/PDF/ZT/A32_R32.pdf">http://www.swisherinc.com/manuals/PDF/ZT/A32_R32.pdf</a></div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">As long as we're talking about awesome vintage mowers, at the steam and tractor show I saw what the dude told me was a vintage Montgomery Ward branded Peerless riding mower, with a rear engine (which was missing) and joystick steering/throttle/brake control. The mower deck looked like gold painted aluminum. It was beautiful, but I can't find anything about it on the internets. I kick myself for not buying it (only $50!).</div>Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com4tag:blogger.com,1999:blog-7740886266706212134.post-47542683241103886992011-11-26T10:50:00.000-08:002011-11-26T10:50:10.556-08:00IntroductionGreetings! I tend to get worked up about things that I find to be awesome, and there are a lot of them. My co-workers suffer daily from me bothering them about whatever the latest thing is, and I initially thought that this blog might help divert some of that from them, but I'll probably still bother them anyway. This blog is entirely self serving; a way for me to bother even more people than just my co-workers.Brian Zhttp://www.blogger.com/profile/03048595222018936495noreply@blogger.com0