My Light Diagram

This burglar alarm system circuit is using a infrared proximity detector that triggers an alarm when the rays falling on its sensor are interrupted. It is different from others burglar alarm systems because is a very simple diy project and can offer you great satisfaction. The circuit of IR burglar alarm system comprises 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. Check out the infrared alarm circuit too. Burglar alarm circuit diagram The transmitted IR signal directly falls on IR sensor TSOP1738. Whenever the IR signal is interrupted, its output pin 3 goes low and IC2 is triggered at pin 5 through transistor T2. As a result, its output at pin 7 goes low (for a preset time) to forward bias siren-driver transistor T2. This condition is indicated by the glowing of LED1. The time-out period can be increased or decreased by changing the value of ...

Description  Circuit showing a Burglar Alarm.Here we have used a ldr and a switching transistor for making this circuit .When the light coming towards the ldr during the period the ldr have low resistance so the buzzer will on.When the light going away the ldr during the period the ldr have high resistance so the transistor will off.Here you need a 12 volt power supply Burglar Alarm Using LDR and BC 548 Circuit diagram    Components Required       Resistor                    10 k(preset)       Transistor                    BC 548        LDR         Buzzer