I’ve tried Nokian Hakkapeliitta W106, Schwalbe Marathon Winter, and Schwalbe Snow Stud.

In general, for my riding (mostly roads, some icy patches, thin-to-no snow), the Nokian W106 is best, especially for the front tire. I think that the Schwalbe Marathon Winter has slightly better rolling resistance, but it is less sure-footed on the ice.

I was quite unhappy with the Snow Stud as a front tire, but it works ok in the rear. The reason for this is that the studs are somewhat to the side; in theory you deflate the tire to get better contact, but that didn’t work for me. In the rear, however, if the tire starts to slide out, then you get contact, and decent traction.

You can see that here, where the two deep scratches on the right (starting just right of center bottom) were made by the studs on the right side of the tire, and the two trace scratches to the let, were made by studs on the left side of the tire, that were much less in contact with the ice.

It looks like it might also give better drive traction in snow, which would be a good thing.

I love my winter biking boots, but they were damnably expensive. A lace broke yesterday, I figured this was a necessary repair. Local Bike Store had no repair kits, I figured I would look online. Landed at their LIFETIME GUARANTEE WARRANTY SITE, entered my info, selected my problem, selected my product from the pictures, asked for two sets of laces, it said “hey, second one’s not free”. Fair’s fair, asked for only one, selected zero-cost shipping, and bang, done.

A warranty, that they clearly mean to fulfil. I feel a little less grumpy about all the money I spent on those wonderful shoes.
PS. Nobody pays me to write this stuff. Normally, I only whine. This was notably better than the usual.

I’m pretty happy with my bike light, but gosh darn it, it could be better!

Various features that I want, but demonstrably don’t need:

• Able to tolerate higher supply voltages.

  The Buckpuck tops out at 32 volts, and the desired voltage for best efficiency is probably closer to 2 times mph — 40v at 20, 50v at 25, and 70 at 35 (which I have surpassed on some hills). Obviously, eventually I am more concerned about the survival of the electronics than I am about perfect efficiency, but I’d like to be moving faster than 25mph before that matters.

  Furthermore, at moderate speeds, voltages above the peak efficiency level allow for lower drag at reduced power. This might be good for daytime running lights, for example.

  There’s at least two ways to get this; one is to disable the voltage doubler once an adequate voltage has been reached, and the other is to choose higher-rated parts.

• Standlight.

  A real one — everything needs to be on at least half power, meaning 2.5 watts. In terms of energy storage, 150 joules per minute, so an ultracapacitor is not a solution. A capacitor holds 1/2 C V2 joules, so a 1-farad ultracapacitor run down to 10 volts (50J) must start out at 20V (200J) — such devices seem not to exist, and certainly not at a sensible price.

• Charge-back into the battery

  Given that a standlight needs a battery, it would be nice to run the battery as long as possible, meaning to put some charge back into it.
  Getting a battery to 100% charge is not a job for amateurs, especially on a bicycle (varying temperatures, varying voltages), but perhaps we can do an approximate job.

• USB charger

  A USB charger needs to supply 500milliAmps at 5volts — 2.5 watts. This is possible either if the lights are low or at good speed. So why not, it would be fun.

• Daytime Running Lights features

  These include, mostly, the ability to blink and do other things to call attention to the bicycle. Reduced power, compatible with USB and/or battery charging, is also a good thing.

• Semi-open, so other crazy people can do more than my already ridiculous set of plans. So, attempt to follow standards set by the Arduino guys, make provision for a crystal good enough to run USB, be sure that one of the connectors could support not just USB charging, but USB communication. It’s not an exact match for the Arduino pinouts, because things just didn’t fit, and because it was important to get the two AC lines to the comparator inputs.

It’s still at the do-I-dare-build-this stage. Not only is it a lot of parts, there’s some surface-mount bits, and SOFTWARE. Said software has the option of setting some (non-essential!) parts on fire, and as a control system, there’s ample room for funny oscillations. However, the big-ass capacitor (4.7 milliFarads) takes almost 5 milliseconds to charge by 1 volt, given a 1 amp input, so there is some wiggle room.

Microprocessor inputs:

• Two ac inputs, to measure wheel rotation
• System voltage
• Rectified AC current
• Four analog lines, for controls
• Four digital lines, for controls/USB
• Programming header, and its lines

Microprocessor outputs:

• Three enable/disable lines to LED power supply, can be PWM’d
• One voltage-doubler disable line (ON by default, so that system powers up fast at low speeds)
• One battery-enable, for charging/discharging the battery. Software has to know what the charging voltage is; current to battery can be estimated somewhat by strobing the lights and battery and monitoring the change in the system voltage; as noted above, a goal of 100% charge is not a good plan.

Behavior, roughly:

• Off, is off. Need to roll the bike to turn it on.
• Slow. Use batteries to keep the lights on. Boost on.
• Medium. Batteries off, boost on.
• Daytime running lights. Lights on steady-dim, pulsing bright.
• Hi/low beams. Of the three LED power supplies, one is high beam, one is low beam, one is rear. Normally the lights are high or low beam.
• USB charging. USB charging will put a load on the supply, which should cause some dimming in order to stay within the power limits.
• Fast. Riding fast produces excess power, which means that it must be dumped somewhere. So, both high and low beams will be activated, as much as necessary to cap the voltage. (Need to put a zener clamp on this somewhere…). One possibility is to dump power into the batteries; for plausible descents, for plausible amounts of battery, the excess energy would “fit” in the batteries, and could then be deliberately run down by powering the lights on full after the descent for a corresponding amount of time.

The weird slots in the PCB planes are intended (not that I know this will work) to provide some noise isolation for the microprocessor and in particular, for its analog side. The switching supplies for the LEDs each put out at least 350mA, switch in the 100s of kilohertz, and could be a tad noisy. The slots under the inductor on the right are intended to reduce eddy currents; the inductor wires are perpendicular to the cuts.

(The PDF images will display in some browsers, or can be clicked for download in others. I need to make them be SVG. Aha, trying to get that done right, that is a problem — a problem caused by misconfigured web servers).

Playing with my bike, playing with my camera.

and the importance of obeying it.Is it really necessary to point out the obvious — that people pick and choose the laws they wish to obey, and come up with all sorts of reasons why it’s ok that they break that particular law — but other laws, those are important.

I’m not arguing that traffic laws should be obeyed to the letter, or breaking them is unsafe — rather, I would like to point out that we already break traffic laws when we think it is safe — and bicycles, who are different from cars (slower, nimbler, better able to see and hear) might be able to do some things safely that cars cannot.

11:34:09

11:34:14

11:34:25

11:35:26

11:36:04

11:37:49

But perhaps stop signs are different. Or maybe they aren’t.

I like my bike, but these are just wonderful. I don’t think I can have all of them.
The Frances Small Haul. Cable steering, a canvas cargo area (got to be good for the wind resistance), pretty-pretty-pretty.

And the Chaise Cruizer. Because, why not?

The chain case serves two purposes; keep my pants clean, and keep the chain “clean”, such as it is.
First, I added what I guess I have to call “pants ramps” or “cuff ramps”. My pants don’t usually catch on the mounting brackets, but last time they did, it was quite a surprise. I was out of the saddle and pushing hard and fast, and OOPS! Turns out they make Sculpey (bakeable plastic modelling clay) in “silver”, and I also had some silver paint. So, I put an 8mm socket on the mounting nuts, and mushed and carved till I liked it. With the soft clay sticking to the chain case, I took the whole thing off the bike and put it in the oven (275 F for 30 minutes). It cooled fast afterwards. I used super glue to fasten the hardened ramps to case, and then put a little silver paint on them to get them closer to the aluminum.

Second, I took a piece of plastic sheet from the hobby shop, cut it to fit the inside of the chain case, marked holes for the mounting pegs, and then cut holes for the pegs, bottom bracket, and the PVC mount. The plan is that this will keep most of the muddy tire splash off the chain.

These bars are Too High. These bars are Too Low. These bars are Too Wide…
I’ve been tinkering with handlebars for years now. The current setup works better than anything I’ve had previously, but scores way high on the dork scale:

The main bar is a Velo-Orange Monmartre bar. I like skinny bars (I’ve tried wide bars, don’t like them) and these are skinny. There’s an upright section for riding upright, but on my old (dropped, 45cm V-O Nitto Randonneur, see banner at top of blog) bars I also spent a fair amount of time on the hoods, so I carried those over. Turns out sometimes I do like to be bent over (especially on a windy day) and the speed picks right up, so with these I can grab the center and rest my elbows on the grips. Maybe I should get some tri-bars, and complete the Franken-bar look.

The vestigial mountain bars below are so I can keep the HANDlebars clean, and so I can fit the SRAM shifter to something.

The only think I don’t like is the weird inward tilt of the brake levers. So this may not be the end; one possibility would be get some narrow mountain-gauge upright bars, put bar-ends where the hoods are, and deploy interrupter levers strategically.

That funny little switch on the left end of the baby bars? That’s my high-beam/low-beam switch.

It was tedious and fiddly to get it on right, but I am happy now.
The rest of this post contains some large photos.

If you go looking for instructions online, you won’t find much. The product page says it “works with modern Sugino Cranks”, and it does, but just barely. My crankset is a Sugino RD2, with a 38 tooth chainring, and a track (103mm?) bottom bracket.

First, the results:

The chaincase mounts on two pegs that strap to the seat and down tubes, and a sort of U-clamp that grabs the chainstay, if there is one.

My plan was to put the nuts on the outside; that might not be quite as pretty, but it was clear that this was going to need fiddling and adjusting, and I have a new chain and chainring in the mail (the old ones are badly worn), so all in all this seemed like the best plan.

The main problem is that the clearance between crankset and chaincase is very small, perhaps a millimeter at best. I spent about a day dry-fitting, not sure if it would work. I had to do the final fitting with the bike laid over sideways and propped up, so I could rotate the pedals freely.

A Big Dummy presents two additional problems, one minor, one tricky. The minor problem is that the down tube is really large, and the supplied mounting strap simply does not fit. Fortunately, I had some stainless steel of the appropriate gauge hanging around, so I cut myself a new strap.

The tricky problem is that there is no chain stay, so the clamp provided with the chain case does not work. The tube has a weird oval section, and is large, so it’s tricky. I started with a trick that my brother told me, which is to make the clamp you need from Fimo or Sculpey:

This worked well enough, but I decided that I could use the Sculpey as a guide to carving (with a Dremel) a piece of PVC pipe:

It’s necessary to drill holes in the chain guard to mount it, so I got as close as I could with the dry fit, and marked marked the chain case with pencil.

Once it was rough-mounted, I used an allen-wrench in the gap between the crank web and the crank arm to be sure it was centered, and tinkered with the mounts to get it right.

Because I wasn’t using the chain stay clamp, I had two spare nuts, so I doubled up on the mounting clamps, mostly because a nut is a smoother and less snaggy surface than a threaded end. I could also Dremel the excess threads off, but that would make it harder to work on in the future, so I decided to start like this and see how things went.

You’ll notice that the rod (below) looks like it is not perpendicular to the centerline of the bicycle; this is intentional, for whatever reason (skinny track BB, probably) if it is perpindicular, it is too long.

I put two holes in the rear part of the chain case above and below the top edge of the PVC; the idea was to pull it tight with zip ties so it could not rotate down. I pulled it tight, checked the clearances, and it was too thick, removed a few millimeters with a power sander, until it was just right.

And it works. I took it for a ride of a few miles, bumps and all, in jeans with no pants clip, and they did not snag (I was a little worried about the mounts) and it did not rub.

My first youtube video. I’d been meaning to do this for some time, the stop sign at this intersection seems to be often ignored. 60 seconds, six cars, no stops.

So if you need a rebuttal to one of those scofflaw-cyclist-ranters that are so common, here you go.

It was supposed to rain, so I was driving to work, saw this out in someone’s trash, and it followed me home. $45 in parts from the Broadway Bicycle School, plus new bearings for the headset, and it’s a bike again.

I have no idea what is going on with the paint job.

I took it to the B’way Bike School on the Big Dummy, which turned out to be a good idea because that way I didn’t need to mess with parking; things were slow enough, they were happy to let me wheel the whole thing in, and then we took inventory of all the missing bits.

The headset was the worst I have ever seen, so I had to rebuild it. The top bearings were full of some crusty stuff, so I cleaned it all out with turpentine. I washed the bearings in turpentine, and when, for grins, I put a magnet on the bottom of the tin, look what stuck:

No, not The Blob. Magnetic dirt, that used to be ball bearings (and races, no doubt). I bought new BBs, from the nice guys at Wheelworks down the street.

There’s a trick for getting old rusted threaded stems loose without destroying the bolt; use a cold pack to cool the stem, and it contracts a hair, and then you can move the bolt. Greased up seven ways to Sunday on reassembly, of course.

(No, it did not get that much shorter, that is after loosening the bolt, on an older bike.)

Front fork was aging fast on the old bike, my brother said his Big Dummy was great, I didn’t get laid off this spring, and the stock is up on solid acquisition rumors. So I bought myself a Big Dummy.
Or rather, I bought a frame and some parts, and reused some from the old bike. The tires, front wheel, handlebars, seat, seatpost, seat lanyard, lights, fender, water bottle cage, front rack, wide loader, and snap deck are from the old bike. Rear wheel, shifters, pedals, botom bracket, crank, chain, brakes, and stem(s) are new. The “chain tensioner” is recycled from another bike. KickBack, I bought from my brother, he notices the weight more than I do. I like it.

Here it is loaded:

Here is the (revised) cockpit. Since the new bike has a threadless fork, I decided to mount all the crap on a second stem. From left to right, bell, lights (hi/lo beams), odometer, coffee, shifter. The circuit-board with blue tape thing is on the rack; it is the power controller for the LEDs, and needs to find a better home eventually.

And yes, that is a fancy headset. The guys down at the LBS did a great job on the hard sell, and the clincher was the multi-year guarantee; given that longtails put double the weight on the front fork, this seemed like an excellent idea. Plus, it’s very pretty.

Chain tensioner. I decided to go with internal gears, eventually I am getting a chain guard or partial chain case (I would love to keep the chain clean in the winer), but the Big Dummy has vertical dropouts so the chain might not always fit right. Plus, with the long chain run, it doesn’t hurt to be sure it stays aligned going onto the rear cog. Using a single chainring and sprocket also meant that I could use a track bottom bracket and crank, and get my feet a little closer together (about 20mm closer together), which I had noticed, riding on a 3-speed, felt better.

Here is most of it, unloaded:

No problems with the internal gears yet; I’m monitoring the adjustment in the beginning (it’s EASY), and once I got the second stem located right, shifting was convenient, and I am not noticing any particular lack of speed. I could well be putting more power (no shock fork, stiffer bike, better Q factor) into a less-efficient drive train, but as long as the net is unchanged, I am happy.

I’m not yet as comfortable no-hands as I was on the old bike, but I expect I will get there. Lightly loaded, it’s fine.

Also: Xtracycle conversion kit (FreeRadical, parts, sideloaders, rear brake and cassette-ready 26″ wheel, plus NEW SnapDeck), one owner, rather used, looking for a good home. Installation help is available.

When I finally tested this circuit on a real bike connected to a real hub, it didn’t work right. I got light, but it was flickery when slow, and I seemed to notice a little more drag (this had to be in my head) than the old 350mA system, and more important, the system voltage never made it above 9 volts; no chance of charging standlight batteries using this design as a starting point. The discrepanies from the plan (too much power to lights at lower speeds) pulled too much current from the hub, so it did not run in the more efficient mode.

I figured out the difference between the model and reality, tweaked the model, and then it tracked observations. With that, I could test a fix before soldering it in, and it worked just fine.

First in-the-field update — vibration cracked off the lead to one of the LEDs, which allowed a test of the voltage shunt. It worked — 300+ lumens from the overvoltage shunt, POW. So the shunt works, too. I haven’t yet managed to activate it with mere speed, up to about 25mph (and now my speedometer is busted, so further measurements need to wait on that).

The fix was to realize that I had not included the resistors used to set the precision voltage sources in my model — they’re voltage sources, PLUS a resistor.

This yields this graph of circuit behavior, which checks out against the actual board. It’s not exactly what I want because the current rises above 200 milliAmps before the cutoff knee, but it’s not far off, and it tests ok in real life.

On the actual bicycle, it has the following desirable attributes:

• Flicker stops between 3 and 3.5mph (5-5.5 kph)
• Lights are on “pretty bright” at 5mph (8kph)
• The system voltage is around 20 volts at 10mph, rising to about 24 volts at 20mph
• The shunt has not yet proved necessary. It trickles about a half a milliamp through the dump, which is more than planned, but not enough to care. This is enough to put the barest light into a power LED.

I have not yet run it down a big straight hill to see if I can force enough current through the shunt to get serious light out of the shunt power LED. The circuit below is the old one, with the obvious repair of the wrong choice of op-amp pinout. For grins, if you view the image and remove the width limit (“?w=700″), you can check my solder work. It’s uneven in two places — the diodes have big wires, in the middle of big pads of copper, and the replaced resistors were done outdoors in the breeze, with a new (and somewhat unfamiliar) soldering iron.

It could still be improved, of course; the board is relatively big and non-compact (then again, that made it easy to work on, so no complaints) and a standlight function would be ducky. I’ll work on that next, in my copious free time.

If you want one of your own, you can get the parts from Digikey, and the PCB from BatchPCB.com. You’ll need to refer to the schematic and board pictures below to get the component values right. Be sure to get an LM258 (not LM358) if you intend to use this in freezing weather.

New board, with fixed opamp selection, and fixed resistor values.

Schematic.

If you want to play with this, here’s all the files.

LICENSE: Creative Commons Attribution-Share Alike 3.0

Gerber files.

Eagle files (board, schematic, library, project).

Qucs simulations.

I decided, that the next circuit I build, will do one thing well, and I’ll worry about the rest later.My brother and I have been over the issue of “what do you want in a bicycle light”, and what we both basically want (and both currently compromise on) is something that is bright as all get out, silent, requires no fiddling to keep it running, and also stays on for a bit when stopped.

Crudely, a “dynamo plus a battery plus LEDs”, but the problem is that you can overcharge your batteries, and the battery control chips that I can find seem to assume conditions that do not hold on a bicycle, like civilized temperatures that don’t change much. So, instead, I plan only to either “do no harm”, which means that the standlight eventually starts to dim and the batteries need charging (that might take months), or perhaps to be far less ambitious in my charging plans — stop at 80%, instead of aiming for 100%. It looks like voltage changes suffice for Sanyo Eneloop, if I stop early (and I want to use Eneloop because they have low self-discharge).

It turns out that 4 lithium batteries would probably be just right. Compact, light, and if you stay below a critical voltage you won’t overcharge them. 3 volts per cell is the minimum output, 4.1 volts per cell is the maximum charge, call it 4 to be safe, and the operating voltage will normally be in the 3.5-3.7 range. Times 4 gives a minimum of 12, usually 14, which is plenty to run the lights at a medium level. I still need to scope out the temperature effects, but wonder of wonders, the ATTiny chips have an on-board temperature sensor.

I also decided that the previous circuit was just too spread out; real estate costs. It should be possible to stand things up, perhaps with some tape and/or glue to help lash them together and cut down on vibration. I also simplified the 3-part ramp to the BuckPuck control, and settled on a 2-part circuit instead. The shunt is not quite as sharp, but is still better than what I am using now.

The trickier part (for me, now merely a hobbyist EE) was to figure out a circuit that could be powered from the battery itself, that would allow current to flow in either direction when switched on, and that could be switched with TTL voltages. Given that, a microprocessor can sit and watch the wheels go round, or not, and watch the system voltage, and when things look slow, it can turn on the batteries. Optionally, it can also turn off the lights, so that they can be blinked or varied while stopped, and it can get limited inputs (inconveniently, using analog-to-digital conversion) on its reset pin.

A bicycle light system does get to play one trick that is not available to (say) a cell phone or a personal computer; it can turn the lights on or off for a few milliseconds while the batteries are charging, and see how the battery voltage responds to the change in the load, and nobody’s going to notice. This might be a good indicator, I don’t know yet. It is, of course, a Simple Matter of Programming.

The software does NOT get to control the shunt that clamps the system voltage below part-frying levels.

The other tricky part is not knowing exactly how much noise there will be in this system.
The BuckPuck is a literal black box, but is presumed to contain a switching power supply. The capacitors feeding it are big. The microprocessor is alleged to need noise reduction, so I took the recommended precautions and followed them as well as I could (so, the ground fed to the voltage dividers for the analog signals, is at the other end of the circuit from the ground feeding the processor, and I decorated the processor with capacitors. Is this enough?

There’s a learning curve. I think I’m past it.
I repaired the busted board. It looks like this:

The so-called second-second-system, using an Atmel168 chip, intended to use Arduino software (minor mods required for lower clock rate), with the option of controlling the LED power profile in software, and also of controlling external electronics.

The pins in a fence around the microprocessor are intended to allow a piggy-back board with additional electronics to be loaded on top. For example, the lights might be controlled independently, or perhaps some rechargeable batteries could be used to provide a standlight, or maybe a USB charger for cellphones and cameras.
Here’s little board to allow a 20+ volt battery pack to be connected or disconnected, under the control of pin B0. Do note, the ability to do battery management is pretty limited — NiMH batteries are finicky, it’s hard to get a good handle on the current going in or out of the battery (10-bit DAC ranging to 5 volts, at best is measuring current through a 1 ohm resistor, with a 5mA resolution. Typical currents will be in the 200mA range, or less, so one part in 40.

I thought about the costs a bit, and had some ideas about simplifying the first board, and arrived at this smaller, simpler board. The shunt comes on a little earlier, but it uses the same ramp-up trick to direct power to the LEDs as the system voltage increases.

Every system is a second system, or so it seems.

Update: it really, really helps to use the right chip. After being incredibly careful about every orientation of every weird transistor, I designed the board around a “LM387N”, which is not the chip I intended or the one that I had ordered — LM258 (usually referred to as LM358, but the 258 works in the cold). I was testing the board before putting on the big components, and it was just not working, and in the end, it seemed like the op-amp was on drugs. In the end, I got out a magnifying glass to check the label. DOH!

All is not lost, but the board needs to be rerouted. I’ll sort out the pins and test again.

Up-update: After installing a pin-scrambler, it works roughly as predicted. The most important part of the circuit, the high-end shunt control, delivers 3.85 volts to the base of the shunt transistor at 31.1 volts. This is a perhaps a half-volt earlier than planned, but it’s a half-volt to the safe side. In the high 20s, the shunt is not activated, as planned.

Anomalies:

(1) the LED control sends a little more power to the lights than I had planned. Not lots, and it’s mostly a low-end effect. At 31.1, the control voltage is 1.7, which is exactly on target. At 22.5 it is 2.6 (plan, 3.1) and at 12.9 it is 3.24 (plan, 3.6) and at 9.6 it is 3.4 (plan, 3.8).

(2) the off-level shunt base voltage is 0.6, where the plan was 0.2. This should not be an issue with the particular Darlington shunt transistor; it claims to have a Vbe of 2.8 volts.

I’ve decided to take the plunge and learn how to get PCBs made.

The new hub (Shimano 3D71) produces too much power, at too high a voltage if your LED circuit does not use it all. The new plan uses a piecewise linear function of the input voltage to drive the voltage control circuit on a BuckPuck, plus a shunt to guard against overvoltage. The idea is that at lower power, enough light is produced, but at high power, the excess is dumped into the lights, with the intent that somewhere between 30 and 31 volts, the LEDs are receiving near-maximum power (9-10 watts), and the shunt is activated to drain up to an amp (30 watts) to keep the voltage from going any higher. The shunt circuit allows an external device (as many as 7 LEDs!) to dissipate the power instead of the transistor. My plan is to use an Endor Star (3 surface mount Luxeon Rebels on a single puck) that I bought but could not find a use for (could not heat sink effectively enough) to dissipate up to 10 watts externally. The goal is to ensure that the supply voltage is limited to 32 volts, no matter what, because the op-amp and the BuckPuck are rated for 32, the capacitors are rated for 35, and the diodes are rated for 40.

The combined circuit is just complex enough that it should be on a PCB, which should also make the result more durable. Vibration on a bicycle is a serious problem.

Resources:

• Digikey

  I buy parts here. I can make sense of their search, they generally have links to the documents that are inevitably necessary to figure things out.

• Sparkfun

  More parts, more discussion of parts, more tutorials. A good place to find answers to Eagle questions.

• Instructables

  This is where I learned how to make autorouting parameters more fumble-fingers-friendly.

• Qucs

  Qucs is a circuit simulator, a little quirky, but it gets the job done, and gives me some confidence that my Great Designs will (or won’t, as the case may be) work.

• Eagle

  CadSoft sells Eagle, software for designing printed circuit boards. The full version does way more than I need; the free version is enough for me, at least so far. The autorouter is mostly my friend, especially once I got used to its quirky habits.

Qucs tips:

• Consider device specs

  Quite a few zener diodes don’t reach their rated voltage until they have quite a few milliamps flowing through them. If those milliamps are also flowing into the base of a transistor then the shunt will have a long, wasteful “on ramp”.

• Consider temperatures

  Diodes, including LEDs, have a forward voltage that increases significantly when the temperature falls from 35 degrees to -5 degrees.

• Consider device precision

  If you want a ramp that comes on at 30.5 plus-or-minus .3 volts, that is a 1% device. That suggests that the resistors had better be at least that good.

• Tinker and fiddle

  Just because it looks like it works, how will it behave in the real world with slightly different parts? Tinker with element values, tinker with resistor gain, try monkeying with the forward voltage on transistors. Push things around till the simulation goes wonky, so that you can know how large your sensible-operation margins are.

Eagle tips:

• Instructables design rule changes
• Pouring polygons, joining nets
• Removing thermals

  In the board editor, click rats-nest to get the polygons poured, then click info on a polygon. One of the info options is a “Thermals” checkbox. You might want thermals; they are intended to make it easier to solder onto a ground plane, which can sink a lot of heat from a soldering iron tip.

• Using restricted areas to make the autorouter behave

  I had a heck of a time get the autorouter to behave, and not rip up polygons. One way to help it is to remove choices; by putting a long skinny polygon of tRestrict or bRestrict, I force it to not cut across some polygons (polygons are optional, tRestrict and bRestrict are not).

• Must have a 3-button mouse

  Working on a Mac laptop, pretty quickly you hit one of those “hit control-right-button for next choice” items in the Eagle UI. Unfortunately, by default you hit control with the trackpad to get it to do “right button”, so you this doesn’t work. A 3-button mouse is a big help. (I went rummaging in System Preferences, and just now discovered the two-fingered “secondary click”, not sure that works with control also).

• Checking design rules
• Important layers
• Checking signals

Schematic

Oh yeah, about the copyright. I’d like to open source it, but cannot figure out how to put the whole GPL on one PCB. I’m a bit ticked off at all the bicycle lighting companies; everything costs too much, way too much. Bought retail, the cost of the components on this board is in the 15-20 dollar range, plus the buckpuck, which is another $15. LEDs+lenses cost about $10 apiece, you need at least 3 for a bike (4 is better), unless you want to also use an LED to help burn off excess voltage. The board itself, quantity 1, costs $45, with shipping and handling. SO, all the parts, except for the hub, cost under $100, and direct 200+ lumens out the front of the bike, and boatloads to the back. Dinotte is probably the best deal out there, and their 200 lumen headlight is $160 all by itself. Add a taillight, another $160. Add a fog/running light, another $160 — here, a fog light costs you an SPDT plus two more LEDs (i.e., $25 more).

This graph shows the intended operation of the varying power control.
At low speeds, the buckpuck is not really on, but if the drive current is low it will start to come on at around 10 volts. 350 mA is the goal; that corresponds to 16 volts, which the hub seems to cheerfully generate if not all its current is sunk. Beyond that, nothing exceeds like excess, we’ve got to do something with the power, might as well turn it into light.

The “efficiency” line is an approximation of the Buckpuck’s predicted efficiency, to allow a rough extrapolation of current draw from the hub/rectifier. The design goal was 200 mA, which correponds to greatest efficiency, according to the data at pilom.com. Higher voltages and lower currents are good; they correspond to lower drag on the bike, and less heat in the hub itself.

The clamp was much harder to get right. “Zener” diodes are not as stable as you might like, and plain old diodes can vary from about 0.6 to 0.8 volts in their forward bias, depending on temperature. It was very helpful to learn that Qucs includes temperature data for many of their devices, so that the shunt could be simulated at various inhumane temperatures. I see this temperature dependence already in the shunt that I use; it comes on more easily when it is cold. So, don’t use Zeners, do use voltage reference devices.

Note: Pr2.I is the current through the shunt. VREFmilliAmps is the current through the voltage reference that controls the shunt. Pr1.V is the drive voltage from the op-amp to the base of the shunt transistor (which is a Darlington, beta of about 20000).

I had to add three devices (two voltage references, and a buckpuck) to the Eagle library. Here they are. The Buckpuck includes a hole drilled underneath its trim pot, if you care to use it. I hope it’s in the right place.

Additional eagle devices

Eagle schematic

Eagle board

I modeled the two circuits separately in Qucs.

Qucs clamp circuit

Qucs varying power circuit

It definitely occurred to me that I could probably program this up with a PIC microcontroller instead (if I could program a PIC microcontroller), and use that to get special modes, allow secondary operation from or charging of batteries, etc. I would not trust the PIC to run the shunt, though.

The general plan would be to feed AC1 and AC2 to a comparator to keep track of wheel rotation, monitor V+ with an A/D to determine the BuckPuck control voltage, and include a current sense resistor on the battery stack to keep track of the cumulative (dis)charge. Outputs would be a relay or MOSFET control voltage on the battery, plus several bits (4?) fed to a D/A (resistors plus an op-amp) to derive a control voltage. So it could definitely be done — but not today.

Turns out I could not help myself; after looking at microprocessor choices, the Atmel chips look like the best bet, mostly because of a better set of tools and community. I planned something that is Arduino-like; it has the same connector, and mostly the same electronics, but some of the pins are different,
and the clock is internal, both for reduced footprint and reduced power consumption. It’s probably best to start with the analog version of this controller first, but this would be a fun project.

I’m still tinkering (I really need to stop), with the current plan being to line up all three headers on the same 1/10 inch grid, so that a daughter board (carrying switching and sensors for battery charging, etc) could be added. One reason for a 3-header daughter board is to make it completely impossible to plug it in wrong, because one of the pins is now the unregulated up-to-32V DC high-power supply. That could cook some parts.

I looked further into battery charging; “optimal” charging is hard, and I think the best bet would be to aim for casual battery management. Since a stack of 20 AA batteries (20-24 volts) could run the lights for perhaps 10 hours at full charge, it is not necessary to aim for 100% charge, and stopping short would be safer. Maybe later.

Today’s lesson: Hub generators are current sources.The sidewall generator was starting to tick me off. Fiddly, the mount cracked once, a little noisy, and too slippy in the winter. So, I took my Christmas money, and bought a custom wheel from a local bike shop, with a Shimano 3D71 in the middle.

Hooking this up to the regulator for the sidewall dynamo worked great, till it failed. Simulation of the circuit revealed two unexpected things; the two small capacitors were probably swinging well past their voltage limits, and they were also getting reverse-biased in the process. However, the part that actually failed, was the power transistor in the voltage clamp; it had gotten so hot that the epoxy on it was cooked to a dark brown. Replacing that transistor restored the clamp to its former function, but this time I added an indicator LED (a power indicator LED) to let me know whether the clamp was running part time, or often. Turns out, the light went on solid at about 10mph, and got plenty bright at 15mph.

Given that the clamp is supposed to only turn on at 23.5 volts, and sinks 350mA, that the hub was delivering somewhere in the neighborhood of 10 watts of power (it’s rated for 3).

It seems a shame to convert all that useful power into heat and transistor flambé. Plan B, is to string all the power LEDs I’ve got kicking around into one big load, and either switch that on with the clamp, or maybe just use that for the clamp. Eight LEDs would be a little pricey, but wow, think of the light.

Or maybe I could run a stereo.

A dynamo-or-battery-driven set of lights for a bike — 200 lumens white to the front, amber low beams and running light, and a red-orange tail-light. It’s about a 3-watt system, using mostly-latest LEDs from CREE (white) and Luxeon (amber and red-orange).Parts, not including spare tape, solder, hardware, etc.

Low beams. Notice the sharp cutoff. This was taken with a flash.

High beams. Some cutoff, but not as much.

The little blue box. The rectifier is below, the regulator and plugs for rear and running light, are above.

Bikes win for delivering packages to the post office, at least until everybody does it and I can no longer park the bike right in front.

his has come up twice in the last week; I want high/lo beams, and I think Wiley needs them too. Different reasons — I don’t want to be rude to peds and other bikers, and Wiley (I think) just needs to conserve power.
The thing to note is that LEDs in the amber-orange-red family are much more efficient at lower temperatures, and more efficient at lower currents. For a given amount of heat sinking, you get more light per watt. In Wiley’s case, he has 4 LEDs total, and he wants to run them from 8 AA NiMH batteries. If he runs 2 1Amp BuckPucks, with two lights in series on each, those batteries will drain pretty fast.

So, first, just go for half the power, because 12 watts from 8 AA batteries won’t last long.

Second, by default, run all 4 LEDs in parallel. 250 milliAmps per LED will still produce pretty good light. When they need to be brighter, run them in series-parallel. A DPDT toggle works.

On-off-on toggles are not the best choice, because the current regulator will run at a high voltage when its output is disconnected from the diodes, which is too high for the LEDs when they are turned on again (this is a bigger problem if there is a capacitor on the regulator output). Either a on-momentary or an on-on will do.

It’s also possible to use a second 2PST toggle to turn a second BuckPuck on, or a 4PDT on-on-on to give you low/medium/high output.

I’m not 100% sure how the two current regulators work in parallel, but it’s worth a try.

I got advice to try oversocks for winter-biking-with-cleats from two independent sock sources, so I did, and they worked great. I promptly (more) holes in the bottom, then saw someone at a party with socks reinforced with some weird plasticky goop.Turns out, the plastic goop is tool-handle plastic, available from hardware stores. The socks I use for oversock purposes are made of stretch polarfleece, available from foxwear.net. The polarfleece will not unravel from where you cut holes for your cleat.

To make the socks last longer, you need to reinforce the bottom. For that, you use Plasti Dip

Take your bike shoes, and stick them inside some sort of plastic bag to protect them from the goop (I used newspaper bags). Then put the socks on over the shoes, and pull them tight against the bottom. Pour the plasti dip into a pan you don’t care much about,

and smear it all over the bottom of the shoes. Hang the shoes to drip/dry someplace you won’t mind the smell:
>

(Re)cut holes in the bottom for your cleats after they are dry.

I’ve tried the neoprene thingies that are supposed to go on over your shoes, and these are cheap, and for me, worked better. It may be that my feet are too large for standard-sized neoprene covers.

Relatively cheap, that is.I begin, with an upgrade to the lights on my son’s bike. The LEDs are mounted onto beefy chunks of aluminum that do triple duty as mounts, heat sinks, and (somewhat) light shields. Everything is bolted on, nothing needs to be removable, nothing needs to be recharged. It runs from a (cheap-ish) dynamo.

aluminum plate for rear, pre-drilling

aluminum plate for front, pre-bending, next to mounting bracket

bending front plate

old and new front plates, the new one is wider, for better heat sinking, and to shield rider’s eyes from light.

how to remove an epoxied LED: just bend the plate.
Note how thin the epoxy was on the backside of the LED

new LED(s) for rear taillight(s)

front view

cut enough wire to connect taillight to regulator

an abrasive puck is useful for roughing up the aluminum pre-gluing, and for making the edges not so sharp.

Soldering, sort of. This was my first attempt, I was trying to be methodical, but I gave up and did it free-hand (I’m pretty good)

Soldered and clipped

Trust, but verify. Be sure it’s right before you glue.

Collect all tools, parts, everything, because JB Kwik sets in FOUR MINUTES:

Ready…

Taillight glued, clamped together hard. You want the thinnest possible layer of epoxy.

Headlight glued and clamped. Note that I clamped the old assembly, lens and all. I would not necessarily use JB Kwik for potting the lens; you might not have enough time, and you need to be a little careful to keep it off the lens.

Rear bolted on, wire routed.

Current regulator, in Altoids box (it’s way too large).
LEDs are wired in series.
From-Regulator red, to rear red.
Rear black, to to-front red.
From-front black continues straight on to regulator.
Heat shrink tubing on the soldered joints.

Dynamo, feeding Rectifier circuit

Rectifier circuit (already swaddled in tape, sorry)
red-black to regulator inputs leaves out the top.

The rectifier circuit uses parts that you can order from Digikey. It requires 2 Schottky diodes,

SBG1025L-T-F DIODE SCHOTTKY 25V 10A D2-PAK

(or, cheaper, but minimum quantity 10)
SBG1025L-T-F DIODE SCHOTTKY 25V 10A D2-PAK

1 24 volt Zener diode,

1N5359B DIODE ZENER 24V 5% 5.0W T-18

3 25V 1800 uF capacitors,

CAP 1800UF 25V ELECT FC RADIAL

and (optionally) a ceramic capacitor or two.

CAP CER 10UF 50V Y5V RAD

Use standard 9V connectors to regulator, this allows you to use a 9V battery for quick tests, or a AA battery pack for backup/continuous lighting.

Circuit diagram, TBD. I am not confident that the voltage protection is sufficiently idiot-proof.

Front light, all bolted on.

Rear view.

Close-up of rear light. No lens necessary, you want that light visible from all directions and a big puddle on the ground, too.

This is a bigger bike, with bigger lights, running right at the hairy edge of what the regulator can do. Batteries help.

There are four LEDs, with two whites in front, in series, also in series with a parallel pair in the back. It is important to only parallel-wire similar LEDs — amber, orange-red, and red, can go in parallel, but not red and white. I am using orange-red because it looks red but is a hair brighter to the eye.

The two whites are in front, obviously, the yellow is under the front of the snap deck, and the orange-red is in back. Doing it like this cuts the tail light by slightly less than half, but it also reduces the forward voltage across the pair, which gives me slightly more margin from the regulator (every tenth of a volt counts).

Here’s another shot. The front lights use two different lenses, one flat and wide (16 by 50), other round and medium (32 degrees wide) to generally spread the light where I want it. I aimed the whole show just a hair below horizontal, so as to get light where I need it, but still be visible in front. I don’t know if the faux down-low glow really helps that much, or not, but it might be helpful if I ever have to work on the bike in the dark.

This is sort of what I see. You can sort of see how the two lenses superimpose, there’s a higher bump up of light, and the flat bit off to the sides, but really a lot, straight in front.

seem not to be used for safety purposes.It occurred to me that the primary uses of auto horns are to indicate

• the light is green, I am in a hurry!
• somebody touched me, I am ALARMED!
• you did something stupid!

By the time the horn is honked, whatever danger there was, is past. I don’t think any of these uses justifies the cost and noise of auto horns.

I did, once, see a horn used for safety. A semi-trailer hauling rocks lost its brakes and was headed towards an intersection. He jake-braked and blew his horn all the way into, through, and past the intersection. So, once in 40-some years, I saw a horn used to avert an accident.

Constraints include: black, no stupid name/decorations, fat (2.3″) tire clearance, fenders, rack, chain guard, dropped top tube (“ladies” bike), enough gears.
Nothing works out of the box, but bike work is easy enough. Painting the frame is hard, finding an aftermarket chain guard is tricky, fitting a tire where there is no room is impossible. The candidates (all decent commuter bikes) include:

• Breezer Uptown 8 U frame, steel fork. ($660)
  

  A complete package, but no room for the fat tires. Also not black.

• Biria Easy Boarding 7 ($570)
  

  A complete package, not clear the fat tires would fit. The excessively practical step-through might be a fashion issue.

• Electra Amsterdam Balloon 8 ($650)
  

  This was almost a winner, but for the pedal-forward position. I’ve tried it, it’s not bad, but it’s not great. Also needs fender, chaincase, perhaps a rack.

• Kona AfricaBike ($300)
  

  

  A nice choice, we might even have gone with it, but it wasn’t available in too many shops (2 carry Kona within 25 miles of our home, and the one we visited did not have it in stock. We saw one on the street in NYC, my better half did not allow me to give it a full exam.

  It needs fenders, chainguard, and rack, and it is black, and it is even steel. It’s probably very heavy (so we hear) and comes with at most 3 speeds, which might be ok, but we have a few icky hills.

• Jamis Commuter 3.0 ($550)
  

  A very nice-looking bike, needs a rack and chainguard, but lacked adequate tire clearance.

• Retrovelo Paula ($2000)
  

  Lacked only rack, chainguard, and affordability. Not black, but very stylish.

• Gary Fisher Simple City ($550 3-spd/$880 8-spd w/ rack)
  

  Another nice-looking bike, needing only a rack (in 3-speed model). 8 speeds includes rack, but neither has adequate tire clearance.

• Novara Flirt ($399)
  

  Needed fenders, rack, and chainguard, but had tire clearance. Was decorated with icky flowers and a great big “Flirt” logo. Yuck.

• Giant Simple ($300)
  
  

  We ended up getting this bike. It needs fenders and a rack (rack already purchased) but it has tire clearance, it’s black, it’s easy to work on. It has 7 exceedingly cheap speeds that I expect I will be replacing if the bike gets any serious use at all.

This just in

(too late for purchase):
Biria Classic Dutch

So, supposing you obey all the laws, have lights and reflectors, wear a helmet, and are generally prudent. What else can you do to make your bike safe?
I found myself chatting with another biker on the trail last weekend, and I found myself pointing out things I had done for safety.

Those are:

• Disk brakes
  Stop in the rain, stop in the snow, can get insanely hot without melting or failing. I love them. As a surprise bonus, if you break a spoke, it’s merely ugly, because the rim is not whapping into the brake caliper.
• Fat tires
  Big, 2.3 inch, fat tires. Rolling resistance is low, bumps are cushioned and don’t reach the rim. The tires won’t even fit into sewer grates or (most) railroad tracks, so that problem is solved. Because they are so fat, their sides are not “steep”, and they are less affected by cracks and irregularities in the road. Unfortunately, lots of bikes lack the clearance for really fat tires. You can get a chain interference, too.
• Xtracycle Free Radical
  I carry cargo, and this puts it behind me, low, and in front of the rear wheel. That means that I am less likely to flip, the bike is less likely to wiggle weirdly from the load, and the extra length makes me more stable. “Track stands” (almost) are easier; rear wheel skids, though slightly more common when unloaded, are slower and allow more time for recovery. If you didn’t want to do the xtracycle thing, you could also get a Coffee Bike, a Yuba Mundo, or a Kona Ute

People have studied how much energy it takes to produce food. It’s interesting. You should read about this, too.The definitive book to read seems to be Food, Energy and Society, edited by D. Pimentel and M. Pimentel, published in 1996. They studied the energy cost of obtaining food in many, many different ways. The main result is that high-productivity farming (like the kind we practice in the US) uses a boatload of energy. Converting grain into meat by feeding it to mammals (cattle, pigs, sheep) uses many calories of grain to create one calorie of meat, so meat is even less energy-efficient. There’s a huge amount of information in this book, much of it interesting, some of it depressing. It will make you want to tear your hair out every time you hear someone talking about farming fuels; odds are, it just won’t work. Besides the fertilizer inputs, there’s also water, and the fertility of the soil. (People need to get serious about driving less, and driving much smaller cars, and they need to do this as soon as possible.)

This paper (which is more quickly accessed) builds on this to demonstrate just how much energy this is, and also studies the greenhouse gas effects (which are not 100% correlated with energy). Animals, and their manure, produce both methane and nitrous oxides. The difference in greenhouse gas emissions between a meat-heavy diet (generally, a typical US diet), and either a vegetarian, or poultry-light diet, can be as large as the difference between driving an SUV and driving a Prius.

It’s also interesting, and depressing, to study the behavior of what I can only call energy-gluttony-apologists. If we cannot get more people to understand what is (probably) going on, we are so screwed. Even one meter of sea level rise will do a lot of damage to coastal cities all around the country, never mind other countries. It’ll mess up drainage and mess up water tables, even if it doesn’t directly flood property.

What I find most incredible is the notion that we simply cannot cut back; that no car can have fewer than 100 horsepower (I learned to drive in a 45 HP car, a Saab 96 with a filthy 2-stroke engine); that our cars must be gigantic; that bicycling is not an option; that every meal must have meat. The stories that people construct in their head to justify not changing their behavior are ludicrous — somehow, amoral, profit-seeking corporations (the oil industry, the coal industry, the big ag business, and the auto industry) are giving us the straight talk, but people who spent years in school learning how to study experiments, data, and phenomena to figure out what’s going on — we’re all Bond villains, or something, intent on imposing our diabolical will on the world. Is it perhaps possible that these profit-seeking corporations are being every bit as deceptive and mendacious as the tobacco industry was? It sure seems that way to me. Seems to me that the Bond villains were on the good side of that issue, at least all the ones that weren’t in the employ of the tobacco industry.

And sure, energy gluttony is fun, but given how we produce energy now, it’s got costs. We’ve got to move our asses, right now, and cut back on some of our most-ridiculous overconsumption. Freezing in the dark is no fun, but driving a Civic instead of a HumVee, that is not much of a sacrifice. Chicken, instead of beef, is not much of a sacrifice. Cutting meat portions in half, is not much of a sacrifice. If you can afford to replace your old crappy leaky windows with new ones, that’s costly, but new windows are actually nicer. LED under-cabinet lighting is expensive, but you get a good light, it takes up no space, lasts a dozen or so years in ordinary use (7+ years if run continuously) you get your choice of (and can mix and match) color temperatures, and it doesn’t get fire-starting hot like halogens and incandescents. That’s not a sacrifice. Places where there’s lots of sun and not much freezing weather, should move to install solar hot water heaters, right now. In southern states that is low-hanging fruit.

Riding your bike a few dozen miles per week may sound like a sacrifice to people who have never done it, but it will help you live longer, and live healthier. I’ve tried dieting to keep weight off, and THAT is a sacrifice. Biking, I lost 20 pounds, and it stayed off. If I don’t bike, something goes wrong with one of my knees, and the doctors I discussed this with suggested that if I didn’t like surgery, perhaps I should keep on biking. Surgery, that’s a sacrifice.

More on this.

And from the National Corn Growers Association.

Two more from Pimental, including the alarming/surprising estimate that we consume more energy than plants create from sunlight.

My lights are generator-driven, so I don’t get much of a chance to see what they look like.

I was out on a snowy day, lights on of course, and took a few pictures of the lights, attempting to catch them from the relevant angles.

From the side, you can see the yellow flare is in fact bright:

High and in front, you can see all three lights. This much above the horizontal the flare is not doing that much, the yellow spot is visible, not blinding, and it catches a bit of the white.

This is pretty much straight-on into the white. It’s bright; even tinkering with the contrast, the rest of the picture is dim (this was mid-day, in a snow storm).

The yellow spot never gets to show much, but I know it works because far-away reflectors are illuminated in yellow.

Had to fix and retrieve a bike from work. Solution? Bike to the bus in the morning, bus to work.

and later, bike back to Alewife, pick up the other bike, and tow it home, complete with wheel-driven generator, because it was, after all, dark.

The astonishing yellow reflection is from a newish Rivendell pants “clip”.

Happily, the Raleigh survived its day at Alewife without any evildoers noticing what a cool vintage bike it was, or peeking under the saddle cover to discover the Brooks Flyer underneath.

80 minutes of major bicycle infrastructure advocacy (and the slides). Everyone should watch this.

Cars, mopeds, motorcycles, and busses, behaving badly

Angles morts A day in the life of a Parisian cyclist

Bicyclists behaving badly

Bike messengers are on crack.
(Lucas Brunelle video) Kids, don’t ride like this.

Mexican highway on a bicycle
(Lucas Brunelle, with intolerable music)

Riding on the Charles
(Lucas Brunelle, better music) Looks like fun to me, if you can avoid the thin ice.

London Calling – Bike Messengers Race (Lucas Brunelle). These guys are somewhat less restrained and careful than the New York messengers. Once again, not an instructional video.

Boston Bike Messenger
(more Lucas Brunelle, apparently his first)

Amazing grace

Fixed Gear Bike Tricks by Ines Brunn
I need to work on my balance a little bit.

Synchronized!

Iron chef? No, iron bike

I can’t do THIS on my bike. I think I would break my neck if I tried. More by the same guy: “Love your job”, indeed.

Amazing race

A great race

Track stand at a sprint.
After you. No, after you. No, really, I insist.

Nice skidding

Excerpts from Eddy Merckx hour record ride, 1972

Team pursuit, England vs Australia, 2004

Going really, really fast on a bicycle.
DeciMach!

Art, such as it is.

The finest set of rollers I’ve ever seen

Giant stuffed animals doing bike tricks in a music video!

Rotary flash mob

Recreation

Cycleball, a sport I had never heard of.

Bike Descent of Tajumulco Volcano
Kinda like those truck commercials where they photoshop it or helicoptor it onto the top of a mountain, only for real, on bikes just like the one I ride to work. More of the same.