In this tutorial we are going to learn, How to make “Door Opening Alarm”.

For this we required:-

  • Resistors (R1:- 1M, R2:-680 Ohms)
  • Capactiors (C1:- 2.2/50V)
  • Transisters (T1,T2:- BC547)
  • 1 LED 5mm Red LED
  • 9V Battery Snapper
  • VK 571 PCB

Lets start to make “Door Opening Alarm”

This inexpensive project can be used as Door Opening Alarm. A magnet operated reed swtich is connnected to the circuit operating buzzer.Here Reed switch acts as a Sensor to detect the door position (close/open). The Reed switch is a small device and contains two ferrous materials inside.This swtich is kept on corner of frame of door and magnet is fixed on moving part of door using adhesive as shown below : When door is closed,magnet comes close to reed swtich. Then reed swtich is closed ,i.e. terminals are shorted.

Then buzzer does not sound. when the door is opend slightly, magnet moves away from reed swtich. Then reed swtich is opened. As  a result alarm is activated. When door is closed, alram is automatically swtiched off. For demonstration of this alarm a 9 volts battery can be used. For continous use a battery eliminator with battery backup can be used.


About the author

Abhay Kalmegh

Hey Guys, I’m Abhay Kalmegh, I’m a Electronics hobbyest and digital marketing nut – it’s my career, hobby, and passion.

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