How to connect MQ2 Gas Sensor with Arduino

Overview

In this tutorial, we will learn how to make a gas leakage detector using an MQ2 gas sensor with Arduino. This is an experimental project of Arduino. But it is not very reliable for serious applications.

You can watch the following video below:-

Components Required

The required components list for this project given below:-

• Arduino Uno
• MQ2 Gas Sensor
• 16*2 Lcd Display 
• 10k Potentiometer
• 220-ohm Resistor
• Buzzer
• Breadboard
• Some Jumper Wire

Pinout

Circuit Schematic

The circuit diagram of the MQ2 gas sensor interfacing with Arduino has been given below:-

Fig: Arduino and MQ2 gas sensor interfacing

Circuit Diagram

Source Code

The source code is given below:-

 #include <LiquidCrystal.h>  
 LiquidCrystal lcd(2, 3, 4, 5, 6, 7);  
   
 #define buzzerPin 10  
   
 #define gasPin A0  
   
 void setup() {  
  Serial.begin(9600);  
  lcd.begin(16, 2);   
    
  pinMode(buzzerPin,OUTPUT);  
   
  lcd.setCursor(0, 0);  
  lcd.print("Calibrating");  
   for(int i = 0; i <10; i++){  
    if (i==4)  
    {  
      lcd.setCursor(0, 1);  
      lcd.print(".");  
     }  
     else lcd.print(".");  
    delay(500);  
    }  
   lcd.setCursor(5, 1);  
   lcd.print("done");  
   delay(1000);  
   lcd.clear();   
   lcd.setCursor(1, 0);  
   lcd.print("SENSOR ACTIVE");  
   delay(1500);  
   lcd.clear();  
   
 }  
   
 void loop() {  
    
 int gasSensor = analogRead(gasPin);  
   
  if (gasSensor > 350)  
  {  
    digitalWrite(buzzerPin,HIGH);  
    lcd.setCursor(0, 0);  
    lcd.print("Value : ");  
    lcd.print(gasSensor);  
    Serial.print(gasSensor);  
    Serial.print("\t");  
    lcd.setCursor(0, 1);  
    Serial.println("Gas is Detected");    
    lcd.print("Gas is Detected");   
    delay(300);   
    lcd.clear();  
  }  
  else if (gasSensor < 350)  
  {  
    digitalWrite(buzzerPin,LOW);  
    lcd.setCursor(0, 0);  
    lcd.print("Value : ");  
    lcd.print(gasSensor);  
    Serial.print(gasSensor);  
    Serial.print("\t");  
    lcd.setCursor(0, 1);  
    Serial.println("No Gas");   
    lcd.print("No Gas");    
    delay(300);  
  }  
    
 }