The author built this converter for a bike dynamo…but I could see it being applied for anything that is generating via a small motor to power a USB device.
http://www.instructables.com/id/5-USB-on-your-Bicycle-Dynamo-in-3-steps/?ALLSTEPS
The author built this converter for a bike dynamo…but I could see it being applied for anything that is generating via a small motor to power a USB device.
http://www.instructables.com/id/5-USB-on-your-Bicycle-Dynamo-in-3-steps/?ALLSTEPS