A Simple Door Alarm Using a Clothes Peg
This is a short YouTube video from DrScrew channel that shows you how you can make a simple door alarm with items lying around your house. Below is the video from their YouTube channel and if you have a slow connection, I have screenshot some of the important steps on how to make the alarm.
How to make a simple door alarm by DrScrew
First, you will need a spare clothes peg like this one above.
Then, you will need a glue gun.
Using the glue gun, glue 2 AA batteries onto the peg, one on both side just like what is shown above.
Drill a hole through the tip of the peg.
Fix a small screw into the hole.
Prepare your buzzer for soldering. You can use any buzzer you can find from your old mother board or old electronics appliances that have one.
Glue the buzzer to the peg.
Solder the buzzer wires to the tip and to the battery terminal.
Solder a wire to connect the 2 batteries terminal. Please note the polarity of the battery.
Solder the other tip with a wire and connect to the other battery.
Now make a contact blocking sheet like this.
Slide it in between the peg tip. If you pull it out, the buzzer will sound.
This is a simple demonstration how you can apply on a door. If anyone were to open the door, the alarm will get triggered and buzzzzz!