How to make Smoke Detection Alarm using Arduino?

Arduino is an open-source electronics platform based on easy-to-use hardware and software. Arduino boards can read digital & analog inputs from the sensors and The MQ2 smoke sensor is sensitive to smoke gases like LPG, Butane, Propane, Methane, Alcohol, Hydrogen.

In this article, We will learn how can we make a Smoke Detector Alarm using Arduino. When the MQ2 Gas Sensor will detect the smoke level high, the red led will glow and the buzzer will start.

Components Required

• Arduino UNO -> A microcontroller board based on the ATmega328P
• MQ2 Gas Sensor -> Which detects the level of smoke
• Buzzer -> A device that produces sound or alarm
• 5V LED -> A Light-emitting diode that emits light 
• 100ohm Resistor -> To resist the current
• Jumper Wires -> For connecting the elements of the circuit

Circuit Diagram

circuit diagram

In this circuit, the MQ2 gas sensor detects the level of smoke in the environment and sends the analog value to the Arduino. which compares the value with the standard value if the value is higher, Arduino sends the signal to the led and the red light will be illuminated and the buzzer will be started. otherwise, green led will be illuminated.

Pins Connection

• Arduino Digital pin 0 is connected with the (+ve) pin of Buzzer
• Arduino Digital pin 1  is connected with the (+ve) pin of LED1(green)
• Arduino Digital pin 2  is connected with the (+ve) pin of LED2(red)
• Arduino Analog pin A0  is connected with A0 Pin of MQ2 Gas sensor
• Arduino 5v Power pin is connected with VCC pin of Gas sensor
• Arduino GND Power pin is connected with GND pin of Gas sensor
• Arduino GND Power pin is connected with (-ve) pins of LED’s with resistance
• Arduino GND Power pin is connected with GND pins of a Buzzer with resistance

Arduino Code

//stored pins in variables

#define gasSensor A0
#define buzzer 0
#define ledGreen 1
#define ledRed 2
#define HIGH 600

void setup() {

   //Initialising all pins
   
   pinMode(gasSensor, INPUT);
   pinMode(buzzer, OUTPUT);
   pinMode(ledGreen, OUTPUT);
   pinMode(ledRed, OUTPUT);
  }

void loop() {
  //Read data from the sensor
int gas_value = analogRead(gasSensor);


//check data from sensor if there is smoke, if will execute otherwise else will execute
if(gas_value > HIGH)
{
  tone(buzzer,1000,500);
  digitalWrite(ledRed, HIGH);
  digitalWrite(ledGreen,LOW);
  
  
}
else
{
  noTone(buzzer);
  digitalWrite(ledGreen,HIGH);
  digitalWrite(ledRed, LOW);
}
delay(200);
  
}

Simulator :