[LAU] crazy idea

frank pirrone frankpirrone at gmail.com
Thu Mar 4 14:51:10 EST 2010

Wouldn't a simple LED/photodetector pair attached to a simple bracket 
that would straddle the crank gear teeth generate a very useful, and 
high-resolution, train of pulses?  I constructed a wooden ramp with 
sides containing two such pair to conduct basic acceleration experiments 
in a high-school physics lab.  It was easy to write programs to perform 
the detection and timing counts.

In fact, those pulses alone would drive a speaker/headphones in an 
interesting sounding manner much like that aforementioned trading card 
in the spokes arrangement.  You could power the LED by battery or the 
bike's generator, and options for a circuit to process the pulse stream 
could be both simple and richly functional.


More information about the Linux-audio-user mailing list