With a few easy steps build a trip wire!
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Step #1:
Next
- Solder a wire to one terminal of a beeper or buzzer.
Step #2:
Next
- 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.
Step #3:
Next
- 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.
Step #4:
Next
- Complete the circuit by soldering a wire that connects the remaining terminals of the battery pack and the beeper/buzzer.
Step #5:

- 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!