Here's a link if you're not familiar with Shawn Frayne's
Watch out VIDEO!!!! There's a better looking video available on Revver, but here's the youtube. I'll state that the frequency is much higher than it appears in the video, it must be a consequence of the frame rate.
Step 1: The Frame
Step 2: Mount the Voice Coil and Magnets
Step 3: We Need a Way to Attach the Belt
Step 4: At the Other End
Step 5: The Belt
Step 6: Stick It in Your...
Suggested areas for exploration, personal and general.
I didn't rebalance the voice coil, I'd also like to try paring one down to reduce it's mass.
Hand wind (or stack multiples of) the coil to increase voltage output.
Try various belt materials.
Acquire some schottky diodes and make a voltage multiplying rectifier.
perhaps follow that with a blocking oscillator for battery charging.
And finally a Thank You to Alan Parekh for the LED's