Advocacy & Safety - Batteryless bike computer? Freeloading off iwico's idea

http://www.bikeforums.net/showthread.php?t=44020
This guy's got a "friciton-free" bike light that runs a couple of LED's. I wonder how much more it would take to make a bike computer like that or at least enough to power the wireless computer...

Wireless: impossible. But it would be very possible to engineer a wired computer that would use the rotation of the wheel to power itself. The current would be generated from the magnet and would use the wire to transmit not only riding information, but also power for the computer.

That can already be done with current technology. There is one problem, however: some energy must remain in the computer to keep the information on record, and the only way to do that (right now) is with condensers. It's fairly easy to manufacture condensers that will remember the data for 1-2 weeks, but what if you store your bike for a full month or short the contacts when changing a tire? RESET!

When I was at high school (1957) a friend of mine made a speedometer by attaching an AC voltmeter to his dynohub. He explained that the dynohub was an alternator where the voltage was proportional to speed. It didnt work too well because of the internal resistance of the circuitry in the voltmeter. Maybe a modern digital voltmeter would work better.

some energy must remain in the computer to keep the information on record, and the only way to do that (right now) is with condensers.

I'm probably way over my head with this. But, can't a capacitor do the trick. It keeps my durned smoke alarm tweeting for weeks after the battery dies.

My tiny MP3 player keeps songs in it's memory for months on end with the batteries out of it.
There's gotta be some magic pixie dust in it.

My tiny MP3 player keeps songs in it's memory for months on end with the batteries out of it.
There's gotta be some magic pixie dust in it.

flash memory does not require power to hold its infromation, however it does have a limited life of ~10,000 write/cycles.

That can already be done with current technology. There is one problem, however: some energy must remain in the computer to keep the information on record, and the only way to do that (right now) is with condensers. It's fairly easy to manufacture condensers that will remember the data for 1-2 weeks, but what if you store your bike for a full month or short the contacts when changing a tire? RESET!

Mabey Diodes Could fix the reset. I think a good idea would be to have the cyclocomputer write the current statistics to an eeprom or flash after every ride. That would be one ride every day for 27+ years before it wore out.

Wireless: Possible. How? Bluetooth technology. Expensive, yes, but possible.

Wireless: Possible. How? Bluetooth technology. Expensive, yes, but possible.

You can transmit power for the computer over Bluetooth? Please enlighten me, I don't see how this is possible.

Not power, data. Thought you were talking about data. my bad

Actually I think this is all possible. You could power the transmitter for the wireless sensor via induction as others have mentioned. You could also have the computer itself be powered via some sort of Eco-Drive type system such as the one Citizen and some other watch manufacturers use. Heaven knows we get enough vibration and movement of the bike to generate the necessary small amount of power. Then there's also the idea of a solar-recharging computer.