Laser security system using Arduino UNO

A laser based intruder detection system built with Arduino UNO that triggers an alarm when the laser beam is interrupted.

BeginnerFull instructions provided24 hours146

Things used in this project

Hardware components

Buzzer

Photo resistor

Arduino UNO

SparkFun Breadboard Power Supply Stick 5V/3.3V

Jumper wires (generic)

SparkFun Solder-able Breadboard - Mini

Single Turn Potentiometer- 10k ohms

LED (generic)

Software apps and online services

Arduino IDE

Microsoft Visual Studio 2017

Story

In this project, implemented using an Arduino Uno board, we have used a photoresistor (photocell) and a red laser LED. The analog values from the photocell are read through analog pin A0. If the sensor value on pin A0 is less than 800 (which indicates an obstacle blocking the laser beam — this threshold was determined using the Serial Monitor), pin 13 of the Arduino, which is connected to an LED and a buzzer, will be activated. Otherwise, pin 13 remains off. The sensor data is also printed through the serial port, allowing us to monitor the status of pin A0 at any given moment.

Laser code

void setup() { 
 pinMode(13, OUTPUT); 
 Serial.begin(9600); 
} 
 
void loop() { 
  int valA0 = analogRead(A0); 
  int valA1 = analogRead(A1); 
  Serial.print("A0: "); 
  Serial.print(valA0); 
  Serial.print(", A1: "); 
  Serial.println(valA1); 
  
  if (valA0 < 800 ||valA1 > 300) { 
    digitalWrite(13, HIGH); 
  } else { 
    digitalWrite(13, LOW); 
  } 
 
  delay(100); 
}