1. 5 volt battery 1. 5 volt mini buzzer Cardboard (like from a cereal box) Electrical tape Glue Insulated wire (3 strands, small gauge) Piece of plywood (4x12 in (10. 2x30. 5 cm) or larger) Tape measure (or measuring stick) Wall hangers (glue-based, removable) Wooden clothespin (with spring) 3 - 5 ft (. 91 - 1. 5 m) of string Wire snips (or sturdy scissors) Wire strippers[1] X Research source
Generally, you’ll want to attach your piece of wood close to the top of the door, within a foot (30. 5 cm) from the door frame. Alternatively, you can place the alarm flat on a desk, nightstand, or bookshelf positioned close to the door so you don’t have to hang it. An alarm that’s high up will be harder to reach and deactivate. Doing this, however, might require more string. [2] X Research source
Measure the wires with a tape measure or measuring stick and bend the wires where you will cut them. This will make it easier to cut accurately. If you find that your scissors don’t cut the wire well, a sharp knife, like a utility knife, can work as a substitute. [3] X Research source
Scissors or a utility knife can also be used to remove insulation. Cut the insulation until you hit the metal wire on the inside, then peel off the insulation. If the insulation doesn’t come free easily, use a pair of pliers to grip the insulation firmly and pull it off. [4] X Research source
Your buzzer may come with screw holes. For a sturdier alarm, you can screw your buzzer into the wood. Be careful to use short nails so these don’t protrude through the board.
When the pin closes, the wires should touch. This will complete the circuit that sets off your alarm. [7] X Research source
Alternatively, your buzzer may have wire leads coming off of it. Strip these, if necessary, and twist your non-battery wire to the positive buzzer wire.
Any non-conductive material will work to break your circuit. Try small pieces of paper, wood, or rubber. You may need to fold thin cardboard so there is more distance between wires. Very thin cardboard may not reliably keep the circuit broken. [11] X Research source
After you finish attaching the wire to the buzzer, cover any remaining bare wires with tape. While the circuit is engaged, touching bare wire will result in a shock. Be careful not to knock out the circuit breaker between the wires of your clothespin. Doing so will complete the circuit, and likely cause a small shock when you try to attach the wire to the buzzer. [12] X Research source
The ends of stripped wire on the clothespin should be in good contact. If they aren’t or are just barely touching, wrap more wire around the clothespin. When adjusting the clothespin wires, disengage your battery from the circuit to prevent getting shocked. [13] X Research source
To improve connections between wires, wrap wires together. After that, tape bare wires to prevent accidental shocks. To improve the connection between connectors, use pliers to coil the end of the wire in a small circle. The circle should be small enough to fit against the connector. Tape the wire circle to the connector. In some cases, you may have a faulty buzzer. Test your buzzer by hooking it up to a traditional power source as directed in the buzzer directions. If it doesn’t work, your buzzer is faulty.
A clothespin is small enough that general purpose glue or hot glue should work to fasten it. For best results, you may want to use a sturdy glue or a wood glue.
Make sure the string is firmly attached to the cardboard. The door may be opened suddenly. If weakly fastened, the string may pull free while the cardboard remains. In this case, the alarm will not go off. [15] X Research source
If your door is painted or made of a nice material, you may not want to tape the string to it. Some tape, when peeled away, can damage paint or wood.
