Low-Cost Laser Security System with Intrusion Detection and Alert Mechanism

Abstract

Security becomes necessary factor nowadays. The crime gang improves their technology to perform their operation along with the development of technology. Hence, technology of security should be more improved to protect the crime works. We have decided to make a security project. In this project we have used laser light for security purpose. We know laser light goes through long distance. When any person or object passes through the laser line, the security alarm will start to ring. There are two parts of the system. One is transmitter and other is receiver. The transmitter side consists of a pair of dry cell batteries and an on-off switch. The receiver side, there is a focusing LDR (Light Dependent Resistor) sensor to sense the laser ray. It is connected with the main driver circuit which has two parts. One is signal of discontinuity ray and other is alarm circuit. When anybody passes through the ray, the main circuit sense the discontinuity and turn on the alarm circuit. The alarm will be ringing until the off button is pressed. There are two methods of ringing. One is the duration of ringing depends on preset timer and another is reset manually. Any option can be set by DPDT switch. We have used second method for our project. Mirrors are attached at every corner to reflect the ray coming from the laser. The reflected ray coming from the last mirror will hit the LDR directly. The system has built with low cost and high performance. The power consumption of the system is very low.