This instructable goes over how to create a generator to power lights, charge a battery or capacitor, etc. with kinetic energy.
Stepper Motor (with 4 cables)
a load to charge or power
Step 1: Create a Bridge Rectifier Using 8 Diodes in a Diamond Formation
Step 2: Bridge Rectifier Breadboard
Step 3: Another View of the Breadboard With Everything Plugged In
Here is a project that I created using this circuit:
Circuit Board (A board that lights up using the kinetic energy of the spinning wheel)
RosediC made it!