How to Make a Simple Home Door Alarm

Cut a piece of wood or heavy cardboard to 12 by 18 inches. Use the wood or cardboard as a building area for the alarm.

Connect one of the insulated wires to the positive (+) end of the battery. Attach one of the uninsulated wires to the negative (-) end of the battery. Use small pieces of electrical tape to hold the wires in place. Tape the battery to the upper left hand corner of the wooden board with duct tape.

Attach the other insulated wire to the positive (+) connector on the buzzer. Connect the other uninsulated wire to the negative (-) connector on the buzzer. Tape the buzzer to the upper right hand corner of the board with duct tape.

Twist the end of the positive wire from the battery to the end of the positive wire connected to the buzzer. Tape the wires together with electrical tape so they do not come apart. Tape the wires down to the board with duct tape so they remain in place.

Wrap the free ends of the uninsulated wires around the opposite sides of the mouth (closed end) of a wooden clothespin. You will need a clothespin that is spring loaded. Squeeze the legs of the clothespin to open the mouth. Wrap several inches of the uninsulated wire attached to the battery to one side of the mouth. Wrap the other side of the clothespin mouth with the uninsulated wire attached to the buzzer.

Release the legs of the clothespin so the mouth closes and the uninsulated wires touch. The buzzer should now begin sounding. Insert a small piece of cardboard into the mouth of the clothespin so it will separate the wires and stop the buzzing while you finish working.

Tape or glue the clothespin to the wooden board with duct. Set the clothespin on one side, so you can still push down to open the mouth. Tape the leg to the board in the lower right hand corner. Use a very strong glue it you don't want to use tape.

Tape one end of the string to the cardboard sitting inside the mouth of the clothespin. You may need to remove the cardboard from the clothespin to do this. Place the cardboard back inside the clothespin when your are finished.

Set the entire wood board (or heavy cardboard) near the door to which you want to attach the alarm. You can screw the board to wall if you wish, but you can just place it on a nearby table or even on the floor.

Tie the other end of the string to the doorknob of the door. Move the board far enough away from the door so the string is pulled tight. When the door is opened, the string will pull out the cardboard inside the clothespin and allow the wires to touch, which will sound the buzzer.