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How to Use MQ131: Examples, Pinouts, and Specs

Image of MQ131
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Introduction

The MQ131 is a gas sensor designed to detect ozone (O₃) concentrations in the air. It operates on the principle of resistive change, where the sensor's resistance varies based on the presence of ozone. This analog output can be used to measure ozone levels, making the MQ131 an essential component in air quality monitoring systems.

Explore Projects Built with MQ131

Use Cirkit Designer to design, explore, and prototype these projects online. Some projects support real-time simulation. Click "Open Project" to start designing instantly!
Arduino UNO Based Air Quality Monitoring and GSM Notification System
Image of Arduino wild: A project utilizing MQ131 in a practical application
This circuit features an Arduino UNO microcontroller interfaced with an MQ135 air quality sensor, an MPU-6050 accelerometer/gyroscope, a SIM900A GSM communication module, and a buzzer. The Arduino reads analog data from the MQ135 sensor and communicates with the MPU-6050 via I2C, while also controlling the buzzer and handling serial communication with the SIM900A module. The purpose of this circuit is likely to monitor air quality and motion, provide alerts through the buzzer, and enable remote communication via GSM.
Cirkit Designer LogoOpen Project in Cirkit Designer
Arduino-Based Air Quality Monitoring System with Multiple Gas Sensors and GSM Module
Image of AIRMS: A project utilizing MQ131 in a practical application
This circuit is an air quality monitoring system that uses an Arduino UNO to read data from various sensors, including the MQ-7 for CO detection, MQ131 for ozone detection, MQ-135 for general air quality, and a DHT11 for temperature and humidity. The Arduino processes the sensor data and can communicate the results via a SIM800L module for remote monitoring.
Cirkit Designer LogoOpen Project in Cirkit Designer
Arduino-Based Air Quality Monitoring System with MQ Sensors
Image of AIRMS: A project utilizing MQ131 in a practical application
This circuit is an air quality monitoring system using an Arduino UNO microcontroller connected to three different gas sensors: MQ-7 for carbon monoxide, MQ131 for ozone, and MQ-135 for general air quality. The Arduino reads analog signals from these sensors and outputs the readings via the serial interface for monitoring purposes.
Cirkit Designer LogoOpen Project in Cirkit Designer
Arduino UNO and A9G GSM/GPRS GPS-Based Air Quality Monitoring System
Image of A9G Smoke Sensor: A project utilizing MQ131 in a practical application
This circuit features an Arduino UNO microcontroller interfaced with an A9G GSM/GPRS+GPS module and an MQ2 gas sensor. The Arduino communicates with the A9G module via digital pins D11 and D10 for data transmission, and it reads analog gas concentration levels from the MQ2 sensor through analog pin A5. Both the A9G module and the MQ2 sensor are powered by the Arduino's 5V output, and all components share a common ground.
Cirkit Designer LogoOpen Project in Cirkit Designer

Explore Projects Built with MQ131

Use Cirkit Designer to design, explore, and prototype these projects online. Some projects support real-time simulation. Click "Open Project" to start designing instantly!
Image of Arduino wild: A project utilizing MQ131 in a practical application
Arduino UNO Based Air Quality Monitoring and GSM Notification System
This circuit features an Arduino UNO microcontroller interfaced with an MQ135 air quality sensor, an MPU-6050 accelerometer/gyroscope, a SIM900A GSM communication module, and a buzzer. The Arduino reads analog data from the MQ135 sensor and communicates with the MPU-6050 via I2C, while also controlling the buzzer and handling serial communication with the SIM900A module. The purpose of this circuit is likely to monitor air quality and motion, provide alerts through the buzzer, and enable remote communication via GSM.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of AIRMS: A project utilizing MQ131 in a practical application
Arduino-Based Air Quality Monitoring System with Multiple Gas Sensors and GSM Module
This circuit is an air quality monitoring system that uses an Arduino UNO to read data from various sensors, including the MQ-7 for CO detection, MQ131 for ozone detection, MQ-135 for general air quality, and a DHT11 for temperature and humidity. The Arduino processes the sensor data and can communicate the results via a SIM800L module for remote monitoring.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of AIRMS: A project utilizing MQ131 in a practical application
Arduino-Based Air Quality Monitoring System with MQ Sensors
This circuit is an air quality monitoring system using an Arduino UNO microcontroller connected to three different gas sensors: MQ-7 for carbon monoxide, MQ131 for ozone, and MQ-135 for general air quality. The Arduino reads analog signals from these sensors and outputs the readings via the serial interface for monitoring purposes.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of A9G Smoke Sensor: A project utilizing MQ131 in a practical application
Arduino UNO and A9G GSM/GPRS GPS-Based Air Quality Monitoring System
This circuit features an Arduino UNO microcontroller interfaced with an A9G GSM/GPRS+GPS module and an MQ2 gas sensor. The Arduino communicates with the A9G module via digital pins D11 and D10 for data transmission, and it reads analog gas concentration levels from the MQ2 sensor through analog pin A5. Both the A9G module and the MQ2 sensor are powered by the Arduino's 5V output, and all components share a common ground.
Cirkit Designer LogoOpen Project in Cirkit Designer

Common Applications and Use Cases

  • Air quality monitoring systems
  • Industrial ozone detection
  • Environmental research and analysis
  • Smart home air purification systems
  • Ozone leakage detection in industrial settings

Technical Specifications

The MQ131 sensor is available in two variants: low concentration and high concentration. Below are the key technical details for both variants:

Parameter Low Concentration Variant High Concentration Variant
Detection Range 10 ppb to 2 ppm 1 ppm to 10 ppm
Heater Voltage (VH) 5V ± 0.2V 5V ± 0.2V
Load Resistance (RL) Adjustable (typically 10kΩ) Adjustable (typically 10kΩ)
Heating Current (IH) < 120 mA < 120 mA
Preheat Time ≥ 24 hours ≥ 24 hours
Operating Temperature Range -20°C to 50°C -20°C to 50°C
Humidity Range 20% to 90% RH 20% to 90% RH
Output Signal Analog voltage Analog voltage

Pin Configuration and Descriptions

The MQ131 sensor module typically has 4 pins. Below is the pinout description:

Pin Name Description
1 VCC Power supply input (5V)
2 GND Ground connection
3 AOUT Analog output signal, proportional to ozone concentration
4 DOUT Digital output signal (threshold-based, requires onboard potentiometer tuning)

Usage Instructions

How to Use the MQ131 in a Circuit

  1. Power the Sensor: Connect the VCC pin to a 5V power supply and the GND pin to ground.
  2. Connect the Output:
    • Use the AOUT pin for analog readings to measure ozone concentration.
    • Optionally, use the DOUT pin for a digital signal if a threshold is set using the onboard potentiometer.
  3. Preheat the Sensor: Allow the sensor to preheat for at least 24 hours before taking accurate measurements.
  4. Read the Output:
    • For analog readings, connect the AOUT pin to an ADC (Analog-to-Digital Converter) pin on a microcontroller.
    • For digital readings, connect the DOUT pin to a digital input pin on the microcontroller.

Important Considerations and Best Practices

  • Preheating: The MQ131 requires a long preheating time (≥ 24 hours) to stabilize its readings.
  • Calibration: Calibrate the sensor in a controlled environment to ensure accurate ozone concentration measurements.
  • Ventilation: Ensure proper ventilation around the sensor to avoid saturation or inaccurate readings.
  • Load Resistance: Adjust the load resistance (RL) based on your application to optimize sensitivity and accuracy.
  • Temperature and Humidity: Operate the sensor within the specified temperature and humidity range for reliable performance.

Example: Using MQ131 with Arduino UNO

Below is an example of how to connect and read data from the MQ131 sensor using an Arduino UNO:

// MQ131 Ozone Sensor Example with Arduino UNO
// Connect AOUT to A0 pin on Arduino for analog readings
// Ensure the sensor is preheated for at least 24 hours before use

const int MQ131_AOUT = A0; // Analog output pin connected to A0
float sensorValue;         // Variable to store the sensor reading

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
  pinMode(MQ131_AOUT, INPUT); // Set AOUT pin as input
}

void loop() {
  // Read the analog value from the sensor
  sensorValue = analogRead(MQ131_AOUT);

  // Convert the analog value to a voltage (assuming 5V reference)
  float voltage = sensorValue * (5.0 / 1023.0);

  // Print the raw sensor value and voltage to the Serial Monitor
  Serial.print("Raw Sensor Value: ");
  Serial.print(sensorValue);
  Serial.print(" | Voltage: ");
  Serial.print(voltage);
  Serial.println(" V");

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

Troubleshooting and FAQs

Common Issues and Solutions

  1. No Output Signal:

    • Ensure the sensor is properly powered (5V to VCC and GND connected).
    • Verify that the sensor has been preheated for at least 24 hours.
  2. Inaccurate Readings:

    • Check if the sensor is operating within the specified temperature and humidity range.
    • Calibrate the sensor in a controlled environment with known ozone concentrations.
  3. Fluctuating Output:

    • Ensure proper ventilation around the sensor to avoid saturation.
    • Verify that the load resistance (RL) is correctly adjusted for your application.
  4. Digital Output Not Triggering:

    • Adjust the onboard potentiometer to set the desired threshold for the DOUT pin.

FAQs

Q: Can the MQ131 detect gases other than ozone?
A: The MQ131 is specifically designed for ozone detection. While it may respond to other gases, its sensitivity and accuracy are optimized for ozone.

Q: How long does the sensor last?
A: The MQ131 has a typical lifespan of 2-3 years under normal operating conditions. Proper maintenance and usage can extend its life.

Q: Can I use the MQ131 outdoors?
A: Yes, but ensure the sensor is protected from extreme weather conditions and operates within the specified temperature and humidity range.

Q: Why is preheating necessary?
A: Preheating stabilizes the sensor's internal structure, ensuring accurate and consistent readings. Skipping this step may result in unreliable measurements.