electric hand crank generator

This is just an example. When you create your alternator (a new thing), pay attention to the ratio of pinion gears. As a generator I recommend using a car alternator.
Spare parts for this model:
Bearings (internal, external, height):
12,32,10 x2
8,16,4 x2
bolts, nuts
Engine size 35x56
the amperage is 0.1A
using 4 diodes, condensator, stabilizator 5v, usb connector

links to used things:
pulleys:
http://www.thingiverse.com/thing:16627
belt:
http://www.thingiverse.com/thing:2016747
box:
http://www.thingiverse.com/thing:155001