Laser Security system

Abstract 

L.A.S.E.R. light security is a type of security system, that is the system used in many restricted areas like Bank lockers, Defense areas, Museums, etc…...    
The LASER security system is a simplest method of security system and it is very safe too.

Component list

1. LDR

2. TRANSISTOR BC 548 (2 nos)

3. RESISTOR  100 Ω (3 nos)

4. BUZZER

5. LED

6. 5V POWER SUPPLY

7. SWITCH

8. L A S E R TORCH

Circuit Diagram: 

 Circuit of  L A S E R: 

Working:

The working is based on a simple fact behind on the L.D.R .That is at the time of  L.A.S.E.R  beam hit on the L.D.R, the resistance of L.D.R is low. So the current have a tendency to move through low resistance loop. Hence the conduction of current at that time is through the L.D.R. And the circuit is complete without flowing through the two transistors. 

Otherwise, when the L.A.S.E.R beam is cut or distorted, the light to the L.D.R. is also distorted. So the L.D.R resistance will become high. Hence the current flows through the transistors Q1 and Q2.  Then the buzzer and the L.E.D will be switched on.

Problem faced at the time of making:

The circuit is only worked at the time of distortion of light takes place and the buzzer is switched off  when the light again comes to the L.D.R . So we can’t  analyze the small period of distortion of the L.A.S.E.R. beam.

Solution

•I solved this by using a  Triak