Solve The Case of the Runaway Computers!

[Sandy]

I have a 1998 Serotta, for which I have a Performance Axiom A10W wireless computer. The bike was against a wall in an upstairs room in which I have my desk top computer. I had no problems with the bicycle computer until I bought a new 2004 Serotta (also using another A10W wireless computer). I relegated my 1998 Serotta to the dining room, which is 1 flight down from the room with the desk top computer. The 2004 Serotta took the place of the 1998 upstairs, next to the desk top computer. I started to notice that both bikes were adding miles to the distance feature and the total distance feature (odo) on the bicycle computer. This was slowly happening, even as the bikes were sitting still.

Being the intellectual giant that you all know that I am, I thought that there must be some interference of one bicycle computer with the other, since they are both wireless. To solve the problem, I took the battery out of the old Serotta. But to my pea brain surprise, the new bicycle computer keeps up its silly little mischievous act and still slowly adds mileage each day (about .25 per day I guess).

I thought that perhaps my old Serotta had put some hex on my new Serotta since it had been relegated to the lower floor. I even considered a much scarier thought that perhaps Kevan visited my house and had mysteriously programmed my bike computers to act in a bizarre manner. What do members of the Serotta Forum Brain Trust think????

I would appreciate a resolution of the runaway bicycle computer problem.


Moving as I am sitting still,


SSS

[rwl]

There are, I think, 3 possibilities.
1) set your alarm clock for 3 am, and get up to check if Kevan is riding up and down your hallway.
2) your computer is broken, and is seeing some phantom sensor signal (unlikely)
3) there is some signal coming from somewhere, which your bike's computer is regarding as coming from your wheel sensor.
the way these things work is that there is a little loop of wire in the sensor attached to the fork. when the magnet on the spoke passes the loop, there is a very small currently flow induced (i'd guess on the order of .1 mA). That, in turn, is transmitted as a pulse to your bike computer. The encoding of that pulse is most likely very, very simple. The receiver on the bike computer, in turn, probably has a very simple receiver design.
.25 miles is about 15000 inches. Your bike wheel has a circumference of about 90 inches. So we're looking for something that generates at least 160 pulses, over 24 hours or so. That's pretty darn slow, so I suspect whatever is generating them is doing so at a much higher frequency, and is at the ragged limit of being seen by your bike.
I suspect your PC, of course. I'd go through the components one at a time. Do you have a wireless keyboard? wireless network? If so, turn them each off for an evening. Another candidate could be your computer monitor. Try turning it off. A remote possibility, literally, is a wireless controller for a garage door opener or TV (but most TV use infrared).
Another idea is to use each of these devices in turn, a bunch of times, without moving the bike, and run up and check the bike computer between them. Just because it looks like 160 pulses or so doesn't mean that they're spread out over the 24 hour period. Could be just less than a minute. The bike PC receiver won't be able to samples so fast that they could all be coming in a second (that would mean that it was designed to work up to a 1500 MPH bike speed).
Rick

[Kevan]

that something's putting some distance on those two bikes.

It isn't me. Alas, Sans-mans has yet to offer me his address. In the meantime I'll contnue to roam his neighborhood in hopes of glimpsing a guy fallen in his driveway, astride his bicycle, and making efforts, like a turtle on its back, to right himself.

You gotta admire a guy like our Sans, who stays steadfast to remain clipped in to his pedals, regardless of his riding position.

Yo-da-man!

[Bruce H.]

Do you have a wireless LAN for your computer? Could be dausing interference that affects the bike computers.
Bruce H.

[Needs Help]

In the meantime I'll contnue to roam his neighborhood in hopes of glimpsing a guy fallen in his driveway, astride his bicycle, and making efforts like a turtle on its back to right itself.

lol. :)

[keno]

1. perhaps it's the new forum design,

2. try turning the bikes around and see if mileage begins to erode,

3. try removing the front wheels and see if symptoms continue,

4. try wrapping one of the computers in aluminum foil,

5. have you been taking your medication,

6. you may have SD, or slow display, and as result of your so fast spinning the display becomes backed up and is just catching up with you,

7. call Car Talk, they love stuff like this,

8. put the bikes in Smiley's abode for an evening and see if the problem persists, better yet one bike at time to see if they act differently,

9. take two Gu's and call me in the morning.

keno

ps Aside from 4, or variations on that theme like a lead xray shield you swipe from your dentist, it sounds like a house-wide gremlin, since, if I understand correctly, it is happening both upstairs as well as down. Did you recently get any new electronic devices, big tvs, cyclotrons, monster microwave, maybe a DSL router? Any new neighbors from France? A secret public works project?

[BumbleBeeDave]

What on earth is going on with you? First ripping the crankarms off your bike, and now this . . . ?!?!

Do you have some sort of X-Men thing going? :eek: Remind me not to get too close to you when I come down to DC--I wouldn’t want you to drain my life force or something! ;)

Seriously, though, I would try wrapping something anti-static around the sensor and see if the trouble stops. I’m not sure if aluminum foil will do it or not, but I have one of those anti-static bags left over from when I bought a new hard drive. Let me know if the problem keeps up and I’ll bring it down to DC with me for you. After all, who really gives a Huret Derailleuer what is causing the problem, as long as you can make it stop . . .

BBDave

[Peter]

The idea of the computer transmitting on signal the cycle computer can pick up is interesting and a possibility.

It reminded me that I tried to determine what frequency my wireless computer transmits on. I used an Opto Electronics Scout which reads near field RF and displays frequency from Low Band (30MHz) to UHF (800MHz). I held the antenna right next to the cycle computer's transmitter but couldn't pick up a thing.

[J.M. White]

Have you considered that your computer is accurate, and that bike fairies are riding your bike each night?

[keno]

what have you learned about your self-actualized computers since the weekend?

keno

[TmcDet]

Sandy is the average speed for this .25 miles the same as what you average? I think that if you reset the computer when you put the bike up so that we could find out how fast the bike is going on its own we would then have a better ideal of how fast you really are. It could be that you are actually slowing the bike down by pedalling it.

[Ares]

I might be wrong about this but, don't most of today's wireless cycling computers use analog signals, and not digital, so theoretically anything that sends an analog signal can interfere with the computer, hence why in packs other wireless "analog" cycling computers interfere with eachother and other devices?