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.
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Step 1: Building the Lego Base
Follow the photos for details on how to build the base.
Some of the photos include the wired up electronics, ill explain that in the next step.
Step 2: The Electronics
The 3 parts needed for this step are:
- 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.
Step 3: Ad Ons
It is easy to create devices (ex: flashlights) that can be plugged into the motor or the usb port to provide power. For this project I enabled collaboration, so if anyone has any ideas for ad ons let me know and you can put them in.