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Sunday, January 6, 2008

PDA's, cable boxes, and leftover motherboard junk.....

I got the bike computer working, finally. Since it's built from an old PDA that's been in a box of "dead stuff" for years, and I'd never tried to use it, I wasn't sure it would even work at all. I'd tried to do it with a Sony Clie, but it kept crashing during use, and when that happened, I'd have to reload the whole PDA from the PC, since it requires disconnecting the battery to fix it (which loses everything in it); reset doesn't work--that means the Clie can't be used unless I can figure out why it crashes and fix it (probably hardware defect, and probably not fixable by me).

So I dug thru my boxes of collected junk and found a Handspring Treo (black & white screen) that was revivable. I had to take it's totally dead Li-Ion battery out and put the one from the Sony in it (doesn't fit well--too tight), and swap connectors. Also, since I don't have the charger cable for it, I had to solder a connector from a PDA with a broken screen to the charging wires on the battery and run that outside the case, using an old Nokia charger that's rated 3.7v (but is only that under load, as the load drops it gets too high a voltage, and I'll have to regulate it before I can leave it on the charger unattended).

Unfortunately the Treo's celphone RF seems to have something wrong with it that even when I turn that off it still uses a LOT of power, as it stays very warm in the whole shielded area on the board where that stuff is at. There's no way I can see of disconnecting those circuits without keeping the rest of the PDA portion from working; I may try just removing the primary TX/RX analog power output section if I can, and see if that causes the chipset to become inactive (I doubt it will work). The power usage means a fully charged battery that on the Clie lasts for several days before I have to recharge it won't even last 45 minutes *in standby* on the Treo, and max of 20 minutes active usage--barely enough time to get to work from home, and I can't test it the reverse path, because by the time I get done working, it's long dead. Fortunately it does keep enough charge when totally inactive to hold memory, so I don't have to resync it every time it dies, but there's no way I can use it as a bike computer until I fix this. Not exactly square one, but it's a definite setback, with two PDAs I can *almost* use. At least there's hope for the Treo, and not a lot for the Clie. The Treo has the advantage of the flip cover, which protects the screen against random things hitting it during a ride, but lets me still see the display.

The mounting of the Treo is just a right-angle piece of aluminum I bolted to the headlight mount, and a piece of foam glued there to hold it at an angle I can easily see while riding. The Treo's antenna unscrews, and since I don't care about the phone part of it, I just unscrew that and thread it back in thru a hole in the bracket, which holds the Treo in place pretty well. I'll make a better bracket eventually, but this is a quick-release mount that lets me take the Treo off the bike when I have to leave it so thieves don't steal it, or jerks break it just cuz they can. (People do sometimes just break stuff on my bike, not like they were trying to steal it, but like they were just feeling vandalistic that day. I wish I could electrify the whole thing with a non-lethal voltage to teach them a lesson. Only non-lethal cuz I wouldn't want someone accidentally dying because they brushed up against it as they pass the bike rack. But I can't, because that's against the boobytrapping laws here).

Since I wanted to mount the PDA horizontally, using the antenna-screwpoint as the mount for now (it'll never be a celphone for me anyway), I used the Fliphack by Douglas I. Anderson, referenced on the VeloAce page by Mark Hämmerling, to turn the display 90 degrees to make it possible to read it while it's sideways. Only thing I don't like is that every time I have to reset the PDA (a lot right now), I have to tell Fliphack to rotate back to 90 again. Probably won't have to worry once I fix the power-consumption problem.

One issue with the current mounting method is that it is very hard with gloved fingers to reach the power button, which is the only place I can turn the backlight on with, using a doubleclick of it. Almost always, I only get one of the two clicks, so it just puts the PDA in standby instead of turning on the backlight (necessary during night rides). If I permanently use the Treo as the bike computer, I'll make a new big momentary-contact button with a bit of logic to do the doubleclick for me, mounted in the flipcover, to make it easy to toggle the backlight while riding, under any conditions. The flipcover also has a switch in it that when opened will turn on a specific program--it's set by the Treo as the phonebook, and there's no built-in provision to change it, but I read of a control panel hack called ButtonsT that lets you reassign both that and the wheelclick button to anything you want.

Dunno what I will change it to, but probably another free program called Dinky Pad by Edward Keyes, so I can quickly jot something down during a ride without dealing with paper/pen or the Palm's Graffiti system or teeny-tiny keyboard. Just flip open the lid and write with whatever pointy thing I have in hand (preferably the stylus, but even a finger will work for some things)--handy for noting down the license plate of any vehicle that tries to run me over or does something else stupid and illegal that could get someone killed or hurt, or even just writing down that other thing I wanted to get at the grocery store before I forget *again*.

The IR transmitter LED is glued to the inward face of the righthand brake handlebar mount, because that directly faces the sensor-end of the PDA. It's barely visible in the pics, because it is almost black, against the black plastic of the brake mount.

The actual wheel-revolution counter circuit is built from parts off of various dead motherboards, plus a magnetic reed switch out of a very old (and large) calculator keypad. I used a couple little round magnets off an old CompUSA namebadge to glue to the wheel spokes, so the switch is engaged once per wheel-turn. An old project-box about the size of a deck of cards is zip-tied and siliconed to the fork, and contains the jacks and battery and circuit (with room left for two or three more of the same). Eventually I think I'll move the entire electronics to the handlebars, along with any other front-end electronics I add, into a custom-made metal "console" that can survive crashes and direct sunlight better than plastic.

The free VeloAce program can use IR input from the wheel sensor to count revolutions, so I took an old cable-tv-box IR transmitter (supposed to be used to tell your VCR to record by faking it's remote control, you just tape it up next to the remote input face on the front of the VCR) and running that from the wheel up to the area near the mounting for the "computer", so it will be able to send the IR signal to it (the signal is just a specific-duration blink of the IR LED every time the wheel turns). Since it had a handy headphone-sized plug on the IR unit already, I just put a jack off a dead motherboard into the electronics box for the sensors to plug that into.

It's a 3-port jack-stack, so once I find my box of dead headphones, I'll put jacks on both the front and rear wheel-sensors, so I can unplug one or the other for testing if needed. Normally only one sensor is needed, but since I want to do RPM tests of the motor-driven wheel, whichever one that is at the time, I put sensors on both wheels. Only one can be used at a time, so for now I don't have the magnet on the rear wheel glued in place, it just sticks to the spoke-end by magnetism when testing with it in-house (not safe for road conditions, because vibration would probably knock it off quickly). The in-house tests aren't done with the wheel on the ground, so the only vibration is from misalignment and chain-drive, both of which are minimal.

I also did some modifications to the headlight while I was working out a mount for the Treo: I removed the old wallmount cieling-fan-control, since I was only using one switch in it anyway, and put the switch in the top of the headlight. All the wires now run into the back of the headlight thru holes I'd already had drilled into it for a previous mounting I no longer use, and had siliconed shut--I just poked them thru the silicone, so they have a decent rain seal already. It all still is wired the same and does the same things, it's just neater and less stuff on my handlebars, making room for things like the PDA. The images here show it as it's assembled (the electronics board in there is just the inverter for the cold-cathode fluorescent of the headlight, which is all what was in this HP scanner-film-slide-negative assembly originally).

I'd like to replace the CCF with LED's, to drop the power consumption by about 90%, but haven't got enough white or near-white ones that are bright enough in total to give the same light output. I consider the CCF itself to be barely bright enough, and it's pretty dang bright. I'd prefer something that gives off *at least* as much light as a high-brightness automotive headlamp, and preferably twice that, with as much surface area as the existing headlight assembly I have now, but *all* light-emitting, instead of the maybe 40% light-emitting it is now. I want to *be seen*. The light is not really for my own benefit, since I generally have enough streetlamp lighting to see by, but rather it's for oncoming (and other) traffic to see *me*, so I don't get into bad situations both in the dark and in non-optimum daylight conditions.

You might be surprised how quickly a bicycle and rider, even with fluorescent colors all over them, can disappear from a driver's view when passing into the shade from overhanging trees and buildings and whatnot, on a bright enough day. I didn't think it would be possible to *not* see me with the paint job on that bike, and my "Dayglo Avenger" riding gear, but I still seem to have some not-really-paying-attention drivers either honk, swerve, or screech their brakes when they suddenly notice me in the bike lane when riding in areas (such as around Metrocenter) that have lots of shady/bright areas. They have no reason to react the way they do, since I'm in a separately-marked bike lane, out of their traffic lane, and not blocking their path at all, and I'm riding slowly and steadily in a straight path (or curved if following a curved road, but still in the middle of the bike lane, predictable as I can possibly be). I'm certainly not stealthy, nor unpredictable or sudden in my moves, and I look and signal before making any changes in lanes or turning. Sometimes I cannot signal when I stop, but that is why I made my taillight also a brake light, just like a car/truck/etc.

Ah, well, they might react the same to suddenly noticing a car driving alongside them that has been there all along, in a different set of traffic conditions, for all I know. I'd be happy as long as they *do* see me, and keep me in mind when driving near me, not suddenly cutting me off by gunning their engines and making a right turn in front of me where I can't stop in time (still all too common, when all they would have to do is not gun their engine and they'd be able to make their turn safely in the few seconds it would take me to pass the intersection and be out of their way completely and safely).

Someday, perhaps.


  1. Found your blog while do some research on a recumbent trike I am planning.

    I have a HP Ipaq think it is a 1900 series that works, have the charger and sync cable for it that I would like to donate to your project. I think it runs Windows CE.

    I am not blogging my project. Between work and my 4 year old granddaughter no time.

    I have been trying to find something suitable to build a outrunner motor, and found your use of the ceiling fan motor really interesting. Going on a scavenger hut today to see if I can find one I can experiment with.

    I am planning my build with 2 1/2 OD .065 round aluminum tubing for the frame. Front wheel drive with a Shimano Nexus Inter7 internally geared hub with a Shimano Biopace crank. Found the crank on ebay for $10.

    I found these sites interesting.

    This is a company that makes an alloy that is used to weld aluminum with a torch.

  2. I understand not having time to blog the project and still *do* it. :-) If I wasn't out of my usual work (since CompUSA shutdown) and only able to find parttime work, I'd not have time either, but as it is I have time to work on things *and* write about them, at least occasionally. :-) There should even be a new post tonite about the turn signals and such, with pics and video.

    For locating parts to experiment with, you might want to sign up for the Freecycle mailing list in your area. I have gotten a number of things from there, including fan motors and old bikes (always good for parts!).

    The cool thing about a cieling fan motor is that just like a bike hub motor, it has a hollow shaft, and frequently uses identical bearings to that used in scooter wheels, bike rear wheel freewheelers, and skates. All three of the ones I have here use the same bearings that are in my Shimano 6 and 7 speed chainring freewheels. One of the CFMs (the brown one in the video) has a stainless steel shaft that appears to be more than tough enough to use as a hub motor; another seems to be good steel, but the third is a cheap no-name fan with a shaft that almost looks like die-cast metal! (though I am sure it is not, I still would not trust it without testing it to extremes first).

    Two of the ones I have are 9-pole, so if your find turns out to be as well, then you can use a 12-magnet 9-pole approach, wired very simply as ABCABCABC to make a BLDC motor out of it. The hardest part is remachining the outer flux ring to hold the magnets, as it must be done as precisely as possible, or making a whole new flux ring for it from scratch (probably harder). I'm still yet to order my magnets, as I'm still looking for some that are parallelogram-shaped instead of rectangular, as they will reduce the cogging effect that might be felt while riding at low speeds with this as a hub motor. may be able to custom-make them for me, but I haven't asked what the cost would be (I'm afraid to).

    If you find one and open it up, you'll see two rings of coils; one I presume is for medium speed, the other for low speed, and both together is likely to be high speed. You'll probably have to unwind all the existing wire (which on CFMs usually isn't lacquered down due to the low-motor speeds it sees), then rewind it with whatever gauge and number of turns you calculate for the torque and speed you need out of it, vs the magnets you'll be using.

    I keep hoping to run across one of those internally geared hubs cheaply (too expensive for my budget new!). If I'm patient, I'll eventually find one being recycled somewhere. I have some ideas on building one myself, but don't yet have the tools to machine it, and have a few problems I need to solve with the idea first. :-)

    I think yours is probably going to be considerably lighter and better than mine. :-)

    Eric Peltzer's site I've seen, though it looks like it's been updated since then with more info. :-)
    I *really* like the Netherlands site--I've never seen anything like what he has there; I'm going to have to do some rethinking of my ideas, because I really like a bunch of little things in those designs.
    Haven't looked at the last site yet, but will soon. Thanks!

    Now the cross-metallic welding material is an interesting idea. I don't yet have a torch (just a wire-feed flux-core welder, the cheapest thing Harbor Freight had on sale, since I had not found anything affordable used even anywhere else in the more than half a year I'd been looking), but when I do, that stuff should let me do a lot of work I didn't think possible!

    Thanks again!


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