Laser light security system

Laser light security system

A laser light Security System is a type of security and alarm system that use laser light and LDR light dependent Resistor as a light sensor Generally different types of security systems are  use to  protects our homes, lockers offices, and banks etc, from unauthorised access and intrusion. The laser light security system is based on laser light. This security system is the most important and efficient type of security systems. 

It acts as a stand alone security system, which gives some sound or noise as a alarm continuous if any person don't reset this alarm, when it detects any irregular activity,  or this security system can be part of home automation security system which can send a call or a message to the owner ete.

In this project, I have designed a simple circuit by using LDR as a light sensor which acts as a switch and by increasing or decreasing the resistance of the circuit,here the laser light reach on LDR from the laser pointer continue, when laser light not reached on LDR then circuit triggers and give an alarm. 

Table of Contents. 

1) Components Required 

2) Component Description 

3) Circuit Diagram 

4) Working of the Project

1. Components required.

  • LM358 (Op – Amp IC 
  • NE555 (Timer IC)
  • LDR                                                               
  • 3 x 10 KΩ Resistors (1/4 Watt) 
  • 220 Ω Resistors (1/4 Watt 10 KΩ
  • Potentiometer   
  • BC547 (NPN Transistor)     
  • Small Buzzer 
  • 100 nmF Capacitor (Ceramic Disc Type Capacitor – Code 104)   
  • Push Button    
  • Laser Pointer     
  • 9V Battery    
  • Connecting Wires    
  • PCB Plate                                    

2. Components discription 


Laser Pointer

Laser Pointer is use as the main source of light in our projects. I am using a small laser pointer. Which emits red light and the wavelength of the laser light is between 600 nm to 700 nm.

LDR (Light Dependent Resistor)

The LDR is using as a light sensor in this project. the intensity of the light which is falling on the LDR is deceasing the resistance of the LDR is  increases, if intensity of the light is increases then the resistance of the LDR decreases.

NE555 Timer IC

NE555 Timer integrated circuit IC that provides a time delay and also use as a pulse generator. Generally NE555 timer IC call the time delay IC.

NE555 Timer IC have 8 pins 
Pin No  1   -  GND  0 volt 
Pin No  2   -   Trigger 
Pin No  3   -   Output 
Pin No  4   -   Reset 
Pin No  5   -   Control voltage 
Pin No  6   -   Threshold 
Pin No  7   -   Discharge 
Pin No  8   -   Vcc 5 volts Positive Input 

LM358 (OP – Amp) IC

LM358 Op-Amp IC is dual Operational low power Amplifier IC and it is consist two high gain frequency compensator Op-Amp IC. The LM358 is designed for the operation of single supply or split supplies. and here the LM358 is used as a Comparator. 
It also has 8 pins  and each pins having different functions. 

LM 358 IC pins 
Pin No  1   -  Output A 
Pin No  2   -   Input A Inverting
Pin No  3   -   Input A Non inverting
Pin No  4   -   GND Negative supply 
Pin No  5   -   Input B Non inverting
Pin No  6   -   Input B Inverting
Pin No  7   -   Output B 
Pin No  8   -   Vcc 5 volts Positive Input 

3. Circuit diagram 






4. Working of the project






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