Hello, it looks like this was touched on briefly. I have some ideas and questions for the crowd
A friend and myself were brainstorming similiar things some time ago, but more inline with the burning man "Spin" project. This was after seeing the fanscreen product website. We were talking about doing live video using R+G+B LEDs.
Anywho, the pimpstar rims dig thread had a link to tihs project, which is wild. I remember the nick ladyada from the old school #hack scene, I'm guessing your the same person? Also there was a guy named x0x as well. Hmm.
Anywho... the project uses a hall effect sensor and magnet, which would be impossible to easily do on a car/truck wheel. In my case I was thinking it might be possible to use a photosensor, and perhaps a laser diode? It should also be possible to use laser diode to perform communications. I guess one could use a single TTL modulated laser w/ fiber distribution to all of the wheels -- but that might be going a bit overboard. The pimpstar is reported to use 900mhz radio modem modules. I bet a gumstix doing bluetooth or wifi could allow fast data transfer, but not really needed.
So has anyone solved the issue of timing on a vehicle?
What about CPU power? I understand the bike version falls off at 30mph? Simply a matter of processing power or does the rise/fall times of the LEDs and support chips fall into play?
The vehicle I have in mind for this is a 1988 postal truck. It has LED ground effects that are full color pulse width modulated (R+G+B leds)... And a 72" rear projection video screen. In terms of the law I have had no problems with the video screen on while driving around southeastern Virginia, but the LED ground effects would warrant a ticket (as would POV displays on the wheels). But that is only on public roads The Truck should be in an upcoming issue of Make magazine.
Picture (feel free to dig thru the web directories!)
http://users.757.org/~ethan/pics/geek/p ... G_3520.JPG
Anywho -- TIGHT project! Much props.