How to Make a Battery Powered Burglar Alarm

Cut out a piece of cardboard 6 inches square.

Glue a AA battery holder to the right side of the cardboard with a hot glue gun. These holders are available at any electronics store.

Glue an electric buzzer to the left side of the cardboard. This buzzer is also available at an electronics store.

Glue a spring-action wooden clothes pin to the cardboard between the battery holder and the buzzer. The portion of the clothes pin that clips together should should extend 1/2-inch past the edge of the cardboard.

Connect one of the buzzer's wires to one of the battery holder's wires by twisting them together.

Wrap a piece of electrical tape around the twisted wires.

Cut two 12-inch pieces of insulated wire with wire cutters. For both pieces, strip 1 inch of insulation off of one end, and 4 inches off of the other using the stripper attached to the wire cutters.

Wrap the 4-inch exposed wire around the top and bottom clips of the clothes pin. The coils of wire should come into contact when the clothes pin is closed.

Twist the ends of one clothes pin wire with the second wire coming from the buzzer, then twist the other clothes pin wire to the second wire coming from the battery holder. Wrap these connections in electrical tape.

Cut a 1-inch square out of cardboard. Hot glue the end of a 12-inch string to it, then tie a thumbtack to the other end of the string.

Clip the cardboard square in the clothes pin, keeping the loops of wire apart.

Attach the alarm to a door with a loop of duct tape, positioned near the door jamb.

Insert the push pin in the wall on the other side of the door jamb.

Insert a AA battery into the holder.