The burglar alarm system circuit uses an infrared proximity detector that triggers an alarm when the rays falling on its sensor are interrupted. It is different from other burglar alarm systems because is a very simple DIY project and can offer you great satisfaction.
The circuit of the IR burglar alarm system comprises a transmitter and receiver-cum-alarm sections. It works off 6V DC, 500mA uninterrupted supply, and uses low-cost readily-available electronic components. LED2 is used for indicating power-on.
Burglar Alarm Circuit Diagram