what is a good motor/alternator/generator to use for a bike generator that's cheap (under $50, preferably under $20)?
I'm on a budget and the bike is going to be mobile so I need a cheap motor but I also need it to be light. The bike would be used to power a USB hub where any USB powered device would be charged or used. So all i need is 5 V. I don't think an alternator would work becuase they look very heavy and I would be riding about 10-20 mi. round trip. It must be light and as far as attaching it goes I intend to use an instructable on bike generators or just plumbers ties to attach it. The only instructable that met all the requirements I've named that I've seen was http://www.instructables.com/id/How-to-Charge-Any-USB-Device-by-Riding-Your-Bike/
. That motor was too expensive "We decided to stick with our Maxon 90, which was a beautiful motor, even though its cost was $275." . Thus the need for a cheap light motor to charge a USB driven device. By the way, thanks for everyone that has posted so far!