This week in Energy, we learned how to build a circuit to power an Arduino from a generator. In my case, I was using a stepper motor from Sparkfun. Using a combination of capacitors, a bridge rectifier and a voltage regulator, I was able to safely get the Arduino to power up. Unfortunately, I wasn't able to turn the stepper fast enough to keep the Arduino running for a significant period of time. A gearbox would be helpful. But this is a pretty encouraging start!