Making a burglar alarm

You can create a simple and rudimentary burglar alarm mostly with things you already have around the house. It is perfect as a science project or to teach children the rudiments that will serve them for a larger project.


  1. Get a wooden board approximately 20 cm wide by 30 cm long
  2. Glue a battery of 1.5 V to the table in the upper left corner
  3. Removes a piece of 2.5 cm of the cover of the two cable ends electric alarm attached to 1.5V
  4. Paste the alarm to the table in the upper right corner, making sure that one of its wires reaches the battery.
  5. One cable connects the alarm to one end of the battery.
  6. Wrap the second end without cable sheath around each closed parts of a clothes hanger.
  7. Removes a piece of 2.5 cm of each end cover of an electric cable 30 cm long.
  8. Tape one end of the cord to the open side of the battery
  9. Wrap the other end around the closed hook edge and make sure the wires are touching the opposite side of the hook mentioned in Step 6. When the coat hanger is closed, the circuit is complete and the alarm should sound.
  10. Cut a small square of cardboard.
  11. Open a hole in the cardboard square with open holes.
  12. Open the coat hanger and place the cardboard between the two parts of the hook directly between the two wires and let it close around the square.
  13. Cut a piece of string
  14. Tying one end of the rope cardboard square through hole.
  15. Paste the clothes hanger in the bottom center of the timber, so that the hook can be opened and closed.
  16. Tie the free end of the rope to a door or window or whatever you want to protect, trying taut. When the rope is pulled, the cardboard will be pulled out of the clothespin, the circuit is completed by moving the cables and the alarm will sound.