You can make a burglar alarm at home without having to spend a ton of money on equipment. This handy gadget will guard the fridge, the garage or the front door. You can also keep your kids in their room and know if they try to sneak out. The following project simply requires old shoe boxes and other household items.
- Skill level:
Things you need
- Electronic bell or peizo buzzer
- Lantern battery
- Two shielded wires
- Roll of non-insulated copper wire
- Clothes pin
- Thin string
- Card board strips
- Glue or tape
Cut a piece of cardboard in the shape of a small triangle. Punch a hole near one corner of the cardboard with a hole puncher or small screwdriver. Tie a string around the hole. The string should be only 5 inches long at the most.
Test the bell. Connect the bell wires to the lantern battery. If the bell rings, then disconnect the wires. If the bell does not ring, then try reconnecting the wires to different ends of the battery connectors.
Disconnect the battery’s negative wire from the bell.
Wrap bare wire around a clothes pin. Wrap one wire to each end of the clothes pin on the portion that normally remains closed. This is sometimes referred to as the teeth of the clothes pin. The result will be two wire leads trailing off the teeth of the clothes pin.
Tie your wire from the battery to one of the wires on the clothes pin. Connect the free wire from the clothes pin to the battery. Twist the wires together or pinch them together with pliers to ensure a secure connection.
Pinch the clothes pin. The bell will sound. If it doesn’t make any sound, check the wiring to ensure that the separated wires on the clothes pin touch when the teeth are in contact with the wires.
Open the teeth of the pin. Stick the cardboard triangle in the teeth with the point and string facing away from the teeth. The alarm should stop.
Place your entire arrangement in a shoebox. Glue the separate components into place inside the shoebox. Place a weight inside of the box, or apply heavy duct tape to the side of the box and somewhere near the front door of your house.
Tie the end of the string to a longer string, measured from the front door handle to the shoebox. When you open the front door, the triangle will pop out of the shoebox, causing the alarm to sound off the bell.
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