This project describes how to build a hand crank Lego usb charger with parts from a Mindstorms kit and Radio Shack.
The charger uses a Lego motor to generate current which is passed through a voltage regulator and then to the usb port.
It would make a great stocking stuffer for anyone who uses devices that charge via usb. If you are getting it for a person who likes to build their own things, just collect all the parts put them in a ziplock, and put that in the stocking. Then when they want to build it you can show them this instructable.
Step 1: Building the Lego base
Some of the photos include the wired up electronics, ill explain that in the next step.
Step 2: The electronics
- Short lego wire, cut the block piece off one end and strip about a centimeter of the wire off
- +5V Fixed-Voltage Regulator 7805
- Female usb port
Plug the lego wire onto the motor as shown in the photos, test out which wire is positive by connecting the stripped wires to a multimeter and cranking the motor. Wire the positive end to pin 1 (input) on the voltage regulator. Wire pin 3 (output) to pin 1 on the usb port (if staring into the socket while the contacts on the inside are facing down, pin one is the farthest to the left). Wire pin 4 on the usb socket, and pin 2 on the voltage regulator to the negative lego wire.