velosynth

velosynth is an open-source bicycle interaction synthesizer.

it's a small, hackable computer that augments the cycling experience by interpreting speed, acceleration, and other sensor data into useful audio feedback.

uses a makerbot-printed holster to attach a magnet to a spoke of the wheel: http://www.thingiverse.com/thing:1610

more information here: http://velosynth.com
check out our kickstarter project: http://www.kickstarter.com/projects/effalo/velosynth