I bought a set of these today, battery free bike lights using magnetic induction to power 2 LEDs per light, may be of interest to fellow low power tinkerers like me.
http://www.reelight.com/Default.aspx?ID=50
They work well, and could be attached to a simple small vawt for garden illumination also.
Obviously I had to take a look inside the unit to see how they work :-)
They are a simple single coil iron core design - the drag when cycling was completely unoticeable. I suspect a scaled up version would cog pretty badly.
The spoke mounted magnet strips actually have 3 magnets embedded in them with magnet poles positioned North - South - North.
They weren't cheap however, cheapest I found was £21 ($30?)
Never need to buy batteries again though, and safer in the day.
I like them, available worldwide I believe.
Ben.
