Laser Based Security System

Introduction

what is security ? A very simple and common answer , security is nothing but the restriction for unwanted access or unauthorised access to anything. we can design such security system in number of intelligent ways such as:

i.  we can design security system with massaging.
it means, if any unauthorised person want to access anything of yours, you got a quick massage to you mobile about it.
ii. we can design the same system with alarm.
iii. we can design such system where any unauthenticated access may cause senseless.

There are number of ways we can design numerous range of security systems. one very simple and common security system is proposed here which is " Laser based security system" where an alarm is introduced. The purpose is to raise alarm if there is any unwanted access.

Component Required

1. Laser module
2. LDR(light dependent resistance) module
3. AT89S52 (8051 microcontroller by ATMEL Corp.)
4. 11.0592 MHz crystal
5. LED/Buzzer (for indication)

 Circuit Diagram

Source Code

#include<AT89X51.h> /* header for 8051 family microcontroller*/
#define LDR P1_0;
#define LED P1_1;
void main()
{
  LDR=1;   /* make ldr as input pin because it receives the light*/
  LED=0;   /* it is configured as output because it is used for indication purpose*/  
  while(1) 

 {
        if(LDR==0) /* if laser light cut LDR receives 0*/
        LED=0;     /* indicator is active*/ 
        if(LDR==1) 
        LED=1;
      }                                                                                               
}

Description

This system for security uses the combination of LASER light and LDR. The LDR module has an onboard potentiometer to adjust the sensitivity of LDR, so that it only senses laser light falling onto it.

The concept is quite simple and similar to what we see in movies where antique, priceless ornaments are protected under laser lights. As someone crosses these lights, an alarm runs on to indicate unauthorised presence. This project works similarly.

In normal conditions, where there is always laser light falling on the LDR, the LDR module always gives a high signal to microcontroller. When someone crosses this laser light, it will behave as an obstruction between the LDR module and laser light, resulting in no light falling on LDR. In such cases LDR module gives a low signal to the microcontroller, which indicates it to switch on an alarm (or LED in this case).

Here I am using only a pair of LDR and LASER module.

But for better and efficient security results, a group of such LASER and LDR modules can be used simultaneously.

We can also use only one laser light with an optical system which will scatter light on different LDR modules.