Laser Security Alarm System

A Laser Security Alarm System is a simple electronic project used to detect intruders. The system consists of a laser source, an LDR sensor, a transistor, a resistor, an LED, and a buzzer. The laser beam continuously falls on the LDR sensor. When the beam is interrupted by a person or an object, the resistance of the LDR changes. This change activates the transistor, which turns on the buzzer and LED to give an alarm signal. This project demonstrates the practical use of sensors and electronic switching devices in security applications. It can be used in homes, offices, and educational electronics projects.