MQ2 Flammable Gas and Smoke Sensor Module

The MQ2 Smoke Sensor Module is a popular gas sensor used to detect LPG, smoke, alcohol, propane, hydrogen, methane, and carbon monoxide. It's often used in air quality monitoring, fire detection, and gas leak detection systems.

The MQ2 gas sensor is also known as a chemiresistor. It contains a sensing material whose resistance changes when it comes in contact with the gas. This change in the value of resistance is used for the detection of gas.

Technical Specifications:

Operating Voltage: 5V DC
Heating Consumption: ≤ 800 mW
Detection Range: 200 – 10000 ppm
Analog Output (A0): Outputs a variable voltage based on gas concentration
Digital Output (D0): HIGH or LOW based on set threshold (adjustable via onboard potentiometer)

Pinouts:

Connection with Arduino:

Module	Arduino UNO
VCC	5V power supply
GND	Ground
A0	A0
D0	D2 (optional for digital reading)

Sample code:

Analog reading:

int mq2Pin = A0; // MQ2 A0 connected to Arduino A0

void setup() {

Serial.begin(9600); // Start the serial communication

}

void loop() {

int sensorValue = analogRead(mq2Pin); // Read analog value from MQ2

Serial.print("MQ2 Sensor Reading: ");

Serial.println(sensorValue); // Print the value to Serial Monitor

delay(1000); // Delay for 1 second

}

Optional: Trigger Buzzer or Relay When Gas Detected:

int mq2Pin = A0;

int buzzer = 8; // Connect a buzzer or relay to pin 8

void setup() {

Serial.begin(9600);

pinMode(buzzer, OUTPUT);

}

void loop() {

int value = analogRead(mq2Pin);

Serial.println(value);

if (value > 400) { // Set your own threshold

digitalWrite(buzzer, HIGH); // Turn buzzer/relay ON

} else {

digitalWrite(buzzer, LOW); // Turn OFF

}

delay(500);

}

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