MQ-2 Gas/Smoke Sensor with Arduino Interfacing

How does it work?

The voltage that the sensor outputs changes accordingly to the smoke/gas level that exists in the atmosphere. The sensor outputs a voltage that is proportional to the concentration of smoke/gas.

In other words, the relationship between voltage and gas concentration is the following:

• The greater the gas concentration, the greater the output voltage
• The lower the gas concentration, the lower the output voltage
  

The output can be an analog signal (A0) that can be read with an analog input of the Arduino or a digital output (D0) that can be read with a digital input of the Arduino.

Code :-

//Prateek //wwww.prateeks.in //https://www.youtube.com/c/JustDoElectronics/videos int redLed = 11; int greenLed = 12; int buzzer = 10; int smokeA5 = A5; // Your threshold value int sensorThres = 400; void setup() { pinMode(redLed, OUTPUT); pinMode(greenLed, OUTPUT); pinMode(buzzer, OUTPUT); pinMode(smokeA5, INPUT); Serial.begin(9600); } void loop() { int analogSensor = analogRead(smokeA5); Serial.print("Pin A5: "); Serial.println(analogSensor); // Checks if it has reached the threshold value if (analogSensor > sensorThres) { digitalWrite(redLed, HIGH); digitalWrite(greenLed, LOW); tone(buzzer, 1000, 200); } else { digitalWrite(redLed, LOW); digitalWrite(greenLed, HIGH); noTone(buzzer); } delay(100); }

Video :-

GitHub Link