USB SeatPost Charger Project

oh, ok I get what you want... Minty Boost - A small battery-powered USB charger
http://learn.adafruit.com/minty-boost
It has the iphone circuit in it already...

it would be easy to modify the circuit by adding more batteries in parallel - thus give a longer charge.

The dynamo works if you don't have access to power at the end of each day, but it makes a lot of noise, wears out tires, adds to fatigue and the ac to dc conversion loses a lot of power in excess heat...

I'm interested to see what you come up with...

I just ordered one of those minty boost kits. They look ace! I'm going to build one into an old puncture repair kit tin for times when the garmin / phone needs charging in the wild.