DIY: Alarm Systems

Place a 12 by 6 inch piece of 1/4-inch thick plywood on a flat surface. The plywood is the frame to which you will attach your alarm components.

Glue the 1 1/2-volt battery to the plywood. Position the battery so it is on its side, with the negative end (-) closest to the corner, and the positive end (+) facing outwards. Allow glue to dry before proceeding.

Glue a 1 1/2-volt buzzer to the corner directly across from the battery. Allow the adhesive to dry before continuing.

Squeeze open the clothespin and hold it open. Wrap one side of the open clothespin with an inch or two of uninsulated wire. Wrap the other side with the other piece of uninsulated wire. Close the clothespin, the wires should now touch each other.

Glue the clothespin to the corner of the plywood that is directly beneath the buzzer. The wire-wrapped ends, or mouth of the clothespin should face away from the buzzer.

Strip one inch of insulation from each end of the four pieces of insulated wire. Use a pair of wire cutters or strippers. The wires should now have exposed ends.

Connect one piece of wire to each end of the 1 1/2-volt battery. Use some electrical tape to hold the wires in place.

Attach another piece of insulated wire to the top connection site of the 1 1/2-volt buzzer. Connect the other end of this wire to the wire that is attached to the positive (+) end of the battery.

Connect another piece of insulated wire to the bottom connection site of the buzzer. Twist the other end of this wire together with one of the uninsulated wires connected to the clothespin.

Attach one end of the last insulated wire to the negative end (-) of the battery. Tape it in place.

Cut a small piece of cardboard to a square of approximately 1 inch by 1 inch. Tape or glue one end of a piece of string to the cardboard. Insert the cardboard into the jaws of the clothespin. This will prevent the wires from touching and the buzzer from going off as you connect the final two wires.

Connect the wire attached to the negative end (-) of the battery to the other uninsulated wire attached to the clothespin. The alarm is now completed.

Pull the cardboard square out from the clothespin to make sure the buzzer sounds. Place the square back in place to stop the buzzer.

Set the alarm by a door or window to which you wish to attach it. Tie the other end of string connected to the cardboard square to the doorknob. Tape the string the window frame if you are attaching it to a window. The alarm will sound when the door or window is opened and the string becomes tight and pulls the cardboard out of the clothespin.