Build your circuit. Power+wire+proximity sensor+bargraph+buzzer
On the side of the door that you want the alarm to be on, attach the end of the wire, the proximity sensor, the buzzer and the bargraph to the door using adhesive shoes. Make sure that the proximity sensor is directly under the doorknob.
On the other side of the door, attach the battery, power and the other end of the wire.
Turn on the circuit. When you try to open the door the alarm should buzz and light up.
See if your friends can get inside your room without setting the alarm off. (That should be amusing.)
You’re done! I hope you like it!