The Fugue Counterpoint by Hans Fugal

30Jan/127

Motorcycle Wheel Alignment

An important part of maintaining a motorcycle is keeping the correct slack on the chain. Usually this involves loosening the rear wheel nut and using two adjustment bolts (one on each side of the wheel) to set the correct tension. Care must be taken to ensure that the front and rear wheels are aligned, or you get bad wear and handling. When you know they are aligned already, you can just count the "flats" and turn the bolts the same amount. But from time to time, or whenever you're uncertain, you have to align them.

The simplest method is just using the marks on the swingarm. This is what I did the first time, but it felt like the rear tire was out of alignment. A little searching of the web confirmed that these marks are both too imprecise and often just plain wrong. What really matters is not the marks the manufacturer put on, but whether the two wheels are actually aligned.

The most common DIY method is to take a string, hold it taught so that it just touches both edges of the rear tire and extends to the ground at the front tire. Carefully measure on both sides, and adjust until the front tire is perfectly centered. I tried this method after I decided I wasn't sure my wheels were aligned. It was a big hassle, especially with just one person, but eventually I got the hang of it. It felt more accurate than the marks but it still felt wildly inaccurate. Something more rigid than string but still nice and straight may have given me more confidence, but I didn't have anything long and straight enough. It could have been placebo, but it rode a lot better after aligning this way.

By this point it had turned quixotic and I would not rest until I found an easy and accurate way to align my wheels. One search led to another and I eventually stumbled across the ProAligner. I was intrigued—how could a ruler be more accurate? Even one with "scientifically designed" red marks. Being the cheapskate engineer that I am I wasn't gong to shell out even $30 unless I knew it would work, and not if I could make my own.

If you search for more details on the ProAligner, you get not a lot of results that fall in two categories: gushing reviews that may or may not be shills, and skeptical curmudgeons that scream SPAM or dismiss even the idea of aligning your wheels. Nobody bridges the two with important details like what the theory is and why it may or may not work, or how it is even used.

Luckily for you anxious wheel aligners (Yes, I realize it is January. I live in California—deal with it! ;-), I have put the jigsaw together and will now help you decide whether to buy the ProAligner.

First, let's discuss the theory on which it works. It's simple geometry. Center front wheel relative to rear tireAlign rear wheel
You are making right triangles and adjusting the wheels until the opposite sides are the same. First you center the front wheel on the rear tire by sighting down each edge of the front tire, then you align the rear wheel by sighting down each edge of the rear tire. Adjust and repeat as necessary until the rear wheel is aligned when the front wheel is centered. Refer to the figure, and reread this paragraph until you get it because it is the key to the whole method, and the thing that ProAligner hopes to hide from all but those who have purchased their ruler. Once you know this tidbit and how it works, it's a slippery slope to realizing you don't need their product to replicate it.

I approximated their design in CAD (the exact spacing is irrelevant, I think I used centimeters and didn't fret whether my printer scaled it slightly), printed it out, and taped it onto some cardboard. Since I don't have a center stand, and my high-quality bike lift is opaque, I needed to do it on the sidestand, so I cut the cardboard to the appropriate angle.

The first time I tried to use it, I put the ruler at the rear wheel and didn't have the whole process figured out. I thought you just sighted along the front tires and soon realized that this alone was super inaccurate unless you could be sure the front wheel was centered perfectly. With the ruler at the rear wheel, it was impossible to read, even with the "scientifically designed" markings.

The second time, I put the ruler just behind the front wheel and had figured out the key idea of centering the front tire relative to the rear wheel, then sighting the rear wheel to read the adjustment. The ruler was easy to read at this distance. I think even a regular school ruler would be—it was 2–3 feet from my eye. The shadow side of my rear tire was hard to sight because it was all just dark. It would have been easier with better lighting, but it was easily remedied with a piece of masking tape on the rear edge to provide contrast. I was pleasantly surprised that it was not only easy to sight and read (aside from having to literally lie on my stomach), but the readings were consistent and reproduceable. It was fairly close to aligned (from the string method) but needed slight adjustment—it turned out I could distinguish one "flat" of the adjusting bolt. This is quite accurate, and easier than futzing about with strings.

As I see it, ProAligner is clever on several fronts. First, coming up with the idea of sighting down the edges of the tires and realizing that this is quite accurate (like sighting a rifle), that was pretty clever. Then, the folding ruler while hardly novel does make positioning it stable and flexible. Finally, I'll concede that the "scientifically designed" markings are easier to read than a regular ruler. So if you're into supporting clever independent companies or would rather spend some money than spend time making your own, then go buy yourself a ProAligner and rest assured that it is accurate and easy.

I have some other ideas for accurate measuring of alignment if lying on the ground isn't your thing. First, a string-based method that I hope would take away most of the frustration: Get a dowel or 2x4 and accurately notch the width of your rear wheel and the center point between the notches. Run the string from the rear tire (hint, wrap around the tire and anchor on a spoke—tape on the tire doesn't stick well) to the notches and wedge it under the centered front wheel. Now you just turn the bolts until the sides of the string just barely touch on both sides.

Second, a laser-pointer method. This isn't unlike this post which was my original tip on the ProAligner, but I think it's easier than his contraption. Attach two laser pointers to straight 2x4s such that they span the rear wheel and point true and level. Bungee them to the rear wheel such that the lasers hit down by the front wheel. Adjust until the front wheel is centered between the laser points. The success of this depends on how accurately you can true the pointers and whether you can keep them on (or have a friend), etc. You could also forego the boards if you have a friend and just sight the laser down the side of the rear tire (a little red on both edges, and also down on the ground by the front tire), have your friend mark with chalk, then measure.

Well, now you have all my thoughts on wheel alignment. My favorite is the ProAligner method—it's faster, simpler, feels most consistent and reliable, and you can even DIY with a ruler, some cardboard, a utility knife, and some tape.

22Jul/081

Ergonomic Computer Desk

When you hear ergonomics you may think of slick curvy things, and probably not of homemade plywood computer desks. But my as-yet theoretical desk should be the epitome of ergonomics for me.

I'm 6'4" and very few desks are made with someone my size in mind. Add to that the fact that very few desks are made with ergonomics of any kind in mind, and it's a sorry thing indeed.

We were talking about setting up a workspace where I could go to work and not be in the primary living area (aka the couch), but we've since decided I'll just go to school. But for a brief moment my DIY engines revved up and I dreamed up the perfect ergonomic, cheap, sturdy desk.


desk plans

I sat in my favorite chair, in the most comfortable/ergonomic position (definitely not straight up) with the height adjusted to give me a nice foot plant with support but not pressure on my legs behind the knees. Then I had Erin help me with the measurements. Keyboard shelf just above the knees, monitor/laptop at eye level and an arms length away, and wide enough for a keyboard, trackball, and open book (width is negotiable if space is tight).

I was inspired by Kathy's Desk Plan, though I doubt I'll paint mine sky blue. I'll probably stain it. If I can convince Erin to let me build it, that is.

A rather good source for ergonomic info is at Coding Horror. But as I alluded above, my take on ergonomics is slightly different.

First, the only RSI injury I've had was directly caused by resting my forearm on a desk corner (rounded) and using the mouse too much (doing lots of web research). As a keyboardist, I know that the best thing is to not rest your wrists/palm/forearms while typing. The only hope you have of doing this is if the keyboard is low enough that it's about the level of your elbow, or a bit lower. This is the first place most desks go dreadfully wrong. And no, those stupid keyboard trays don't count.

Second, the monitor should be up around eye level and not too close to the face. This is in line with what others say so I won't elaborate.

Third, I simply can not sit up straight for any length of time. It is absolutely impossible, and I believe that even if I could it would be detrimental. Maybe some people are made to sit up straight, I don't know, but I know my body isn't designed that way. Whenever I try it, I end up subconciously resting on my elbows, chin in my palm, with my face right up at the monitor, which is of course bad for my eyes, neck, and wrists. What my body has told me all along seems to jive with recent research. This is the realm of the chair but I mention it for completeness.

Finally, I find arm rests cause problems in my shoulders, elbows, forearms, etc. I highly prefer a chair without arm rests, or where they are adjusted sufficiently low as to be out of the way when typing (and therefore only used for actual rest). Again, this is a function of the chair.

So there you have it. If your wife lets you make one (and you may need to adjust the measurements to fit your body), let me know how it turns out.

24Jun/080

Pipe Dream

So I've been reading up on what makes organ pipes tick (ok, so they don't tick). It's very fascinating and yet very simple. It has surprised even me that it has made me think about making my own.

Now, I'm not crazy enough to build a large organ, at least not without gobs of time and money and the proper tools. I'm still nurturing the dream of building just a MIDI pedalboard, remember.

Still, there is a project that I can see myself taking on someday. I could build a positive organ. ("Positive" rhymes with "beef.") It's a little one-manual organ that has just a couple of stops. It's portable like a dresser with wheels is.

But not just any positive organ. A crazy simple positive organ. I'm thinking PVC pipe, because working with metal and wood intimidates me (and I don't have the tools). That may change before I actually build it. Who needs a case? If I'm going to build a pipe organ it's going to be naked so that people can see how an organ works. So build it onto/into a simple push cart or something. As for wind, what good is a portable organ if you have a loud motor that needs electricity? If I had cash for a nice quiet blower that would be one thing, but since I don't maybe I'll go with a simple bellows like they did in the olde days. Keyboard? Tracker's the only way to go on something like this, which means I'll have to break my anti-woodworking pact. But on a positive organ where the pipes are right there, the action should be simple.

This is very early stages of the dream, but I'm imagining 8', 4', 2', and 2 2/3'. 8' and 4' for sure. Probably 49 notes (4 octaves) on the manual. So that's 100–200 pipes. I hope my attention span is that large. Of course I can always start with one stop and go from there.

You may wonder how I'm going to fit an 8' stop in an organ I pretend will be portable. You can take a 4' pipe and cover the end and it will resonate like an 8' pipe (and though it's not made of wood will hopefully sound not entirely unlike a Gedackt).

If none of that made any sense, just click on this link and say "that'd be cool!"

14Apr/085

DIY UHF Antenna

I had one of these antennas:

RCA VHF/UHF Antenna

Not top of the line, I know, but it did have an amplifier and it did cost probably $30 when I bought it. And it's pretty much worthless. We got the PBS station in town but rarely could we pick up any of the El Paso stations.

Now that we're on the DTV bandwagon, I set out to improve the antenna situation. Antennaweb told me that I should be able to pick up almost all of the stations with a "yellow" antenna—a small multidirectional antenna (actually one station called for a medium directional w/pre-amp, and antennaweb doesn't realize some of those stations are broadcasting digital on UHF channels for now). In other words, it should be easy to get those stations. So I did a little searching and researching. All the digital stations here are UHF, so all I really needed was a UHF antenna.

I decided to make me a simple loop antenna—the same design as the UHF component on the one I already had. I fired up a wavelength calculator and figured out that the center of bandwidth for the channels I was interested in (15,16,17,18,23, I found that with the help of HDHomeRun's Channel Page, although my strongest station was mysteriously absent there) was almost exactly 2 feet (Here is an excellent TV Frequencies Table. Remember λ=c/f=3e4/MHz.). So I cut a coat hanger at 2 feet, shaped it into a circle, and soldered on a female coax connector. There are pictures here.

DIY UHF Antenna

I found that it didn't work much better than the other one in the same position, but as I moved it around and found a good position I got a satisfactory signal. So, to be rigorous, I tried the other antenna in that position. It was pitiful. So I was still justified.

I ended up hanging it on a nail on the wall, where it gets satisfactory to excellent reception for every station. Total cost: under $5.

If you need a directional antenna in your area, you might still be able to do this, and add a reflector (cardboard with aluminum foil) ¼ wavelength on the far side. I held a piece of foil behind it and it improved the signal strength quite a bit. Just how to rig that up is your problem, but I suppose some pieces of 2x6 and some nails and washers (and electrical tape for insulation) would do the job.

Speaking of electrical tape, if you look at those photos you'll see that there is a bunch of electrical tape scraps on my loop. That's just because I reused the hanger from my coat hanger dipole when constructing it. Which is an excellent VHF antenna, if your stations are VHF.

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14Feb/083

On Soapmaking

Previously on The Fugue, I told you how to make Castile Soap in 5 Minutes. Having been through the process a few more times since then, I have a couple of addendums.

First, on measurements. If you're at all serious about making soap you either need to do large batches or get a scale with 1 gram precision. With my old scale (which had 5 gram precision) I had hits and misses with the size of batch that I like. i.e. 1–2 bars worth. Most recipes you find on the internet are what I would deem "large batches", and are really more like medium batches. But when you're trying to nail down the perfect recipe, making 5–10 bars of soap is wasteful, or at least a really really slow way to go about it.

Second, on ingredients. Pure castile soap is great, but has to be treated with respect or it can get really slimy. Coconut Oil is easy to obtain and adds hardness and lather. Lard or tallow is cheap and also hardens the bar. So I've been doing 6 parts olive, 2–3 parts tallow or lard, and 1–2 parts coconut oil and others (like cocoa butter). I calculate the lye then use 2 parts liquid for 1 part lye (by volume). I like to use milk instead of water, because I made this one bar with milk and the caramelized sugars (from the lye heating up when mixed with the milk) made a bar that smelled divine.

Third, on measuring again. For the size of batch I'm doing (on the order of 80 grams fat) I figured out that measurement error gives me ±2%. So I round the lye and fats (check the total weight so the measurement errors don't compound), then add 2g (a bit over 2%) of fat. So I know I'm between just under 1% superfat and 5% superfat, which is acceptable. I don't want more than 5% but of course you really don't want less than 0%. The same idea would apply with a 5g precision scale, but you'd have to be doing batches about 5 times as large (I think).

Fourth, on temperature. I don't measure temperatures. I aim for "warm to the touch" on the outside of each container before bringing them together. Rather than wait for the lye to cool down to "warm", I start with really cold liquid, sometimes in the form of one or two ice cubes. The ice cubes melt, and the final temperature is much closer to the target and so there's much less waiting. Obviously, if you're using more solid fats you want the temperature to be above their melting points until you get a good mixture.

Which brings us to the final point, mixing and molding. I am more than ever convinced that shaking in a water bottle (or large soda bottle) is an excellent way to go. It is safe, convenient, cheap, and fast. However, it's not such a great mold. It will work as a mold, but it will take that much longer to set up (evaporate water). Usually you demold after 1–2 days, but getting cheese-consistency soap out of a water bottle without marring it is an exercise in futility. So now I use paper cups as molds, and I pour the soap in from the water bottle when it reaches trace. As a bonus, you can clean out the water bottle and use it again the next time. It's easy to extract the soap from the paper cups, and they're cheap and nice and round.

So here's an updated base recipe. Go forth and wash!

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26Jan/080

hipmod

When I was in grade school, I used to bring my homework from and to school folded up in my back pocket. Life was simpler then. I always knew exactly what I had on my plate at any moment by checking my back pocket.

Fast-forward to the era of planners, PDAs, and productivity software. I've gone through all the phases. None of them fit, but I took something away from each. These days I know what I want, and none of the traditional solutions come close.

I want something analog, very simple, compact, and easy to put together. When I came across the Hipster PDA I thought I had found it, but I soon found that even the hipster wasn't easy enough. I didn't like even the smallest binder clips or paperclips because they had to be removed to actually use it. Rings didn't suit my fancy either. Loose index cards are of course a disaster. The supply of index cards got almost as unwieldy as the hipster itself. To top it all off, blank index cards alone wasn't quite enough structure. So it fell into disuse.

Then I found the D*I*Y Planner, most notably their Hipster PDA edition. This added some structure and beauty, so I gave it a try. I soon decided that printing onto index cards is completely infeasible without special equipment. So that was out, alas.

The other day, I came across PocketMod. Here was something not entirely unlike the homework in my back pocket. It had some structure, it was easy and simple and cheap. It was perfect, except… I don't want to visit a website and run a flash app every time I want to print one. What if the website disappears? And what if I want to add custom pages? (There's a Windows app for that but I don't use Windows.) Also, the printouts generated by the flash app aren't quite right—the fold points aren't on the center and so the end result is a little sloppy-looking. I wish the US used A4 paper, but that's beyond my control at the moment (though I might consider ordering some online…). So the pocketmod flash applet had to be replaced.

So I decided to combine the D*I*Y Hipster and some scripting magic, and the result is hipmod. Thanks to the magic of Multivalent (I was going to use pdftk but it's segfaulting on my laptop for some reason) I can now create hipmods including whatever PDF of interest I find lying around. See the README for more information. Here's a screenshot:

2-week hipmod

11Dec/070

Castile Soap in 5 Minutes

The other day I was searching for something completely unrelated and came across this amusing video about making Bacon Soap.

The video brought me down memory lane—some years ago we borrowed a book on soapmaking and endeavoured to make soap for Christmas presents. That experiment went wholly wrong and our house smelled like lard for weeks and we had no soap to show for it in the end.

But this video made it look simple and easy, and so on a whim I decided to make soap. I checked for all the ingredients. I had lye, some lard (from my pie crust experiments), some canola and olive oil, and of course water. So I did some research on the web and went to work. A couple hours later, I had soap in the pot waiting to trace ("trace" is a stage the soap gets to, where it's ready to pour into the mold). It waited… and waited… and finally several hours later (after occasional stirring, I'm not stupid enough to stir constantly for several hours) it did trace and I poured it in. Actually I'm not sure it didn't trace earlier and I was just looking for something else.

The next day it was set up pretty well in the mold, well on its way to becoming soap. That wasn't so hard. But I knew it could be easier. So I reformulated, used my imagination (and borrowed some imagination from the web) and tried again yesterday afternoon.

This time I decided to make Castile soap. That is, Olive Oil soap. I didn't want to make much since it's just an experiment. I didn't want to stir a lot. I didn't want lots of dirty dishes. I didn't want to mess around with molds. I wanted the whole process to take about 5 minutes. It does. Here are my instructions for making Castile Soap in 5 minutes (and a few weeks of waiting):

Update: now find this recipe at http://hans.fugal.net/soap/castile.txt.

Enjoy your all-natural castile soap. It's not hard to make, but you may still wonder if it's worth all the trouble. Allow me to quote:

Hand made soap retains extra glycerin, known to soften the skin naturally. Glycerin is one of the best known humecants (attracts moisture to the skin). It is often extracted during the process of manufacturing commercially made soap, then sold as a valuable by-product. Natural ingredients are rarely used in commercially manufactured soap. If used at all, it is sparingly. One of the best advantages of making your own soap is that you are in charge of quality control. You decide which ingredients to use and how much.

If your skin is sensitive to scents, additives, etc., or you need to impress your wife/girlfriend/soon-to-be-girlfriend, then the benefits are even more pronounced.

The soap you end up with will be the same quailty of soap that sells for $5 a bar at health nut^Wfood stores. It will cost you about $1 and 5 minutes of time to make yourself. If you enjoy making soap, you may want to learn more about the chemistry and how to make different kinds of soaps each with their own qualities and benefits, and how to scent and color them into works of art. The internet is full of great instructions, and you can't go wrong once you understand the basics, which are well-put by Caveman Chemistry (though to be honest I skipped all that chemistry junk and got to the practical instructions).

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24Jun/061

IR Receiver

I've always been a software guy. I'm doing good if I can keep up with what good
computer hardware is. But a combination of needing a way to control mplayer
from the couch, poverty, and a desire to learn the useful skill of soldering
drove me to create my own serial IR receiver for use with
lirc.

I was afraid my first soldering project would be a disaster, but it really has
turned out quite nice. At least, it's nice if you don't look at the back. :-)
Check out the pictures on
flickr
.

IR Receiver

I followed the instructions from the Linux Journal
article
, with some modifications. I
didn't want it inside a DB9 case, I wanted to show off my geeky creation so I
didn't cut up the perf board. I didn't want a DB9 connector, I wanted to use
cat5 cable and an RJ45 to DB9 adapter
that I had made previously. I used the IR Receiver from Radio Shack, model
276-640
.
The electronics store didn't have the precise voltage regulator called for but
had one with the same output that could handle higher voltage so I got that
instead.

If I were to start fresh, I would wish I had found these
instructions

instead. The LJ instructions are good, but these ones are better. I think I'd
still use perfboard anyway, since I'm not encasing it in a DB9 hood.

The version of lirc-modules-source in Debian testing at the moment didn't
work for some reason but the version from unstable works fine. I had a hard
time finding out what model my universal remote is, but I was able to create a
lircd config file for my DVD remote easy enough, and irw recognizes it
fine.

I still have to configure mplayer but there should be nothing special to that.
So I declare my IR receiver a success! Many thanks to Von for teaching me to
solder, Jared for helping me in the initial research, and Erin for not putting
up too much resistance to the idea.

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