With a few easy steps build a trip wire!

Project Steps

Solder a wire to one terminal of a beeper or buzzer.

Put two pins or nails into a board.

Put in a third pin with a photo hook pivoting on it. Position the pin so that when the hook swings it will contact one of the other two pins.

Solder the wire from the beeper/buzzer to the pin that the hook will touch.

Solder a wire from a battery pack to the hook.

Complete the circuit by soldering a wire that connects the remaining terminals of the battery pack and the beeper/buzzer.

Tie a string to the hook. Mount the board on one side of a doorway or walkway and stretch the string across to the other side.

Now wait for someone to walk into your trap!