Laser light security alarm

Abstract

The main purpose of this project is to design a Laser and LDR based security system. This is based on the principle of Voltage divider circuit. When the laser beam falls on the light dependent resistor continuously, the p.d. drop across the LDR is very low as the resistance of LDR becomes less. When the beam of the laser light is interrupted by any object or a blockage, the voltage drop across it becomes high due to change in the LDR’s resistance. This triggers the siren / alarm in the circuit. The project is very simple and it will help us learn more about the components that we always study in class and use in our labs. This will increase our knowledge to a larger extent