This is super easy to make and woks supprisingly well!
its pretty cool

Step 1: Pats

Here's The things you need:

1.Lego Mindstorms motor

2.a few lego parts

3.short lego cable

4.an LED

Step 2: Attatch the Cable

Put one end on the contacts, and the other end on the bottom of the motor.

Step 3: Attatch the Crank

stat with putting a 90 degree angle "attacher thingy" (I know,very technical lingo) on the end coming out of the motor. then attatch a "stick" the another "attatcher, then another "stick"

Step 4: LED

Attatch the LED by pulling the leads appart, then wedging it in the bottom of the block on the side free side of the wire. each lead should be toutching the contacts diagonal from eachother