Intruder alarm


How to make your own intruder alarm.

Things needed:


  • 1 x 9V Battery

  • 1 x 9V Battery snap connector

  • 1 x 9V Buzzer

  • 1 x Clothes peg

  • 1 x Sheet of tin foil

  • 1 x Piece of string

  • 2 x Lengths of wire

  • 1 x Playing card 

Tools and equipment

  • Scissors

  • Sellotape

  • Nail clippers 


  1. Strip the ends of the snap connector, the buzzer, and the two lengths of wire, with a pair of nail clippers.
  2. Tear off two strips of tin foil and wrap them around the prongs of a sprung clothes peg.
  3. Tape one end of each length of wire to the tin foil patches on the clothes peg.
  4. Twist the end of the red wire on the buzzer to the end of one clothes peg wire.
  5. Twist the end of the red wire on the snap connector to the end of the other clothes peg wire.
  6. Twist the ends of the black wires on the buzzer and the snap connector together.
  7. Tape a piece of string to the playing card.
  8. Clip the playing card in the clothes peg.
  9. Tape the clothes peg to the wall beside your door.
  10. Tape the end of the string to your door.
  11. Connect the 9V battery to the snap connector.
  12. When an intruder opens your door the card will be pulled out of the peg and the buzzer will sound. 

Further ideas:

Perhaps you could add a light to the circuit too?

Don't forget to share a picture or video of your creation on our Facebook page, we'd love to see it.


Published in the April edition of Dartford Living magazine.