How to Use MQ5 Gas Sensor: Examples, Pinouts, and Specs

The MQ5 Gas Sensor, manufactured by DFRobot (Part ID: SEN0130), is a versatile and reliable gas detection sensor designed to detect various gases, including natural gas, LPG (liquefied petroleum gas), and smoke. It operates on the principle of resistive change in the presence of gas, providing an analog output proportional to the gas concentration in the environment. This sensor is widely used in safety systems, gas leak detection, and environmental monitoring applications.

• Gas leak detection in homes and industries
• Smoke detection in fire alarm systems
• Environmental monitoring for air quality
• IoT-based gas monitoring systems
• Safety systems in kitchens and laboratories

The MQ5 Gas Sensor is designed for ease of use and integration into various systems. Below are its key technical details:

The MQ5 Gas Sensor module has a 4-pin interface for easy connection to microcontrollers or other circuits. Below is the pin configuration:

The MQ5 Gas Sensor is simple to use and can be integrated into a variety of circuits. Follow the steps below to use the sensor effectively:

1. Power the Sensor: Connect the VCC pin to a 5V power source and the GND pin to ground.
2. Read the Output:
   • Use the AOUT pin to read the analog signal, which varies with gas concentration.
   • Alternatively, use the DOUT pin for a digital signal. The threshold for the digital output can be adjusted using the onboard potentiometer.
3. Connect to a Microcontroller: For example, connect the sensor to an Arduino UNO as follows:
   • VCC to Arduino 5V
   • GND to Arduino GND
   • AOUT to an analog input pin (e.g., A0)
   • Optionally, connect DOUT to a digital input pin for threshold-based detection.

• Preheat Time: Allow the sensor to preheat for at least 24 hours before taking stable readings.
• Ventilation: Ensure proper ventilation around the sensor for accurate gas detection.
• Calibration: Calibrate the sensor in a known gas concentration environment for precise measurements.
• Avoid Contamination: Keep the sensor away from water, oil, and other contaminants that may affect its performance.
• Power Supply: Use a stable 5V power source to avoid fluctuations in readings.

Below is an example code snippet to read the analog output of the MQ5 Gas Sensor using an Arduino UNO:

// MQ5 Gas Sensor Example Code
// Manufacturer: DFRobot
// Part ID: SEN0130

const int analogPin = A0; // Connect AOUT pin of MQ5 to A0 on Arduino
int sensorValue = 0;      // Variable to store the sensor reading

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
  Serial.println("MQ5 Gas Sensor Test");
}

void loop() {
  sensorValue = analogRead(analogPin); // Read the analog value from the sensor
  Serial.print("Gas Concentration (Analog Value): ");
  Serial.println(sensorValue); // Print the sensor value to the Serial Monitor

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

1. No Output or Incorrect Readings:

   • Cause: Insufficient preheat time.
   • Solution: Allow the sensor to preheat for at least 24 hours before use.

2. Fluctuating Readings:

   • Cause: Unstable power supply or environmental interference.
   • Solution: Use a regulated 5V power source and ensure the sensor is placed in a stable environment.

3. Digital Output Not Triggering:

   • Cause: Incorrect threshold setting.
   • Solution: Adjust the potentiometer on the module to set the desired threshold.

4. Sensor Not Responding to Gas:

   • Cause: Sensor contamination or damage.
   • Solution: Ensure the sensor is clean and free from contaminants. Replace if necessary.

Q1: Can the MQ5 detect gases other than LPG and natural gas?
A1: Yes, the MQ5 can detect other gases, such as smoke and hydrogen, but it is most sensitive to LPG and natural gas.

Q2: How do I calibrate the sensor?
A2: To calibrate the sensor, expose it to a known concentration of gas and adjust the potentiometer until the desired output is achieved.

Q3: Can I use the MQ5 with a 3.3V microcontroller?
A3: The MQ5 requires a 5V power supply for proper operation. Use a level shifter or voltage regulator if interfacing with a 3.3V microcontroller.

Q4: How long does the sensor last?
A4: The MQ5 has a typical lifespan of 2-3 years under normal operating conditions.