How to Use MQ-2: Examples, Pinouts, and Specs

The MQ-2 is a versatile gas sensor designed to detect a variety of gases, including LPG, propane, methane, and smoke. Manufactured by Arduino, this sensor operates on the principle of resistive change when exposed to target gases. It is widely used in gas leak detection systems, air quality monitoring, and safety applications. The MQ-2 is a cost-effective and reliable solution for detecting combustible gases and smoke in residential, industrial, and commercial environments.

• Gas leak detection in homes and industries
• Smoke detection in fire alarm systems
• Air quality monitoring systems
• IoT-based environmental monitoring projects
• Safety systems for detecting hazardous gas levels

The MQ-2 sensor is designed for ease of use and integration into various electronic systems. Below are its key technical details:

The MQ-2 sensor module typically has four pins. The table below describes each pin:

The MQ-2 sensor is straightforward to use in a circuit. Follow the steps below to integrate it into your project:

1. Power the Sensor: Connect the VCC pin to the 5V pin on the Arduino UNO and the GND pin to the Arduino's ground.
2. Read Analog Output: Connect the AO pin to an analog input pin on the Arduino (e.g., A0).
3. Read Digital Output: Optionally, connect the DO pin to a digital input pin on the Arduino (e.g., D2) if you want to use the digital threshold feature.
4. Adjust Sensitivity: Use the onboard potentiometer to set the desired sensitivity level for the digital output.

The following code demonstrates how to read both the analog and digital outputs of the MQ-2 sensor using an Arduino UNO:

// MQ-2 Gas Sensor Example Code
// Reads analog and digital outputs from the MQ-2 sensor and prints the values
// to the Serial Monitor.

const int analogPin = A0; // Analog output pin connected to A0
const int digitalPin = 2; // Digital output pin connected to D2

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
  pinMode(digitalPin, INPUT); // Set digital pin as input
}

void loop() {
  int analogValue = analogRead(analogPin); // Read analog value from sensor
  int digitalValue = digitalRead(digitalPin); // Read digital value from sensor

  // Print the values to the Serial Monitor
  Serial.print("Analog Value: ");
  Serial.print(analogValue); // Print analog value
  Serial.print(" | Digital Value: ");
  Serial.println(digitalValue); // Print digital value

  delay(1000); // Wait for 1 second before the next reading
}

• Preheat Time: Allow the sensor to preheat for at least 20 seconds before taking readings to ensure accuracy.
• Ventilation: Ensure proper ventilation around the sensor to avoid false readings due to stagnant air.
• Calibration: For precise measurements, calibrate the sensor in a controlled environment with known gas concentrations.
• Power Supply: Use a stable 5V power source to avoid fluctuations in sensor readings.

1. Can the MQ-2 detect multiple gases simultaneously?

   • Yes, the MQ-2 can detect multiple gases, but it cannot differentiate between them. It provides a combined reading of all detected gases.

2. How do I calibrate the MQ-2 sensor?

   • To calibrate, expose the sensor to a known concentration of gas and adjust the potentiometer or use software to map the analog output to the gas concentration.

3. What is the lifespan of the MQ-2 sensor?

   • The MQ-2 sensor typically lasts for 2-3 years under normal operating conditions.

4. Can the MQ-2 be used outdoors?

   • While the MQ-2 can be used outdoors, it should be protected from extreme weather conditions and moisture to ensure accurate readings.

By following this documentation, you can effectively integrate and use the MQ-2 gas sensor in your projects.