Air Quality Sensor MQ-135, MQ Series Sensor for Arduino

Air Quality Sensor MQ-135

The MQ-135 is a widely used air quality sensor capable of detecting a variety of harmful gases. Here’s a detailed overview of its specifications and features:

Key Specifications:–

Gas Detection: Detects ammonia (NH3), nitrogen oxides (NOx), alcohol, benzene, smoke, carbon dioxide (CO2), and other harmful gases.
– Operating Voltage: 5V DC.
– Power Consumption: Less than 150 mA.
– Output: Analog and Digital.
– Preheat Time: Over 24 hours for best accuracy.
– Dimensions: Approx. 32 mm x 22 mm x 27 mm.
– Sensing Resistance: 10KΩ to 60KΩ depending on the concentration of the gases.
– Operating Temperature: -20°C to 50°C.
– Humidity Range: 20% to 90% RH.

MQ-135 Features:

– High Sensitivity to Air Quality: Particularly sensitive to ammonia, NOx, alcohol, benzene, smoke, and CO2.
– Fast Response Time: Quickly reacts to changes in gas concentrations.
– Analog Output: Provides a continuous analog signal corresponding to the gas concentration.
– Digital Output: Threshold-based output that can be set to trigger alarms or actions when gas concentration exceeds a set level.
– Long Life and Stable Performance: Reliable and durable for long-term use.
– Preheat Time: Requires a significant preheat time for accurate readings, typically over 24 hours.

MQ-135 Applications:

– Air Quality Monitoring: Used in indoor and outdoor air quality monitoring systems.
– Safety Alarms: Integrated into gas detectors and alarms to ensure safety in residential, commercial, and industrial environments.
– HVAC Systems: Incorporated into heating, ventilation, and air conditioning systems to monitor and improve air quality.
– Automotive: Used in vehicles to detect harmful gases inside the cabin.
– Home Automation: Part of smart home systems to monitor and maintain healthy indoor air quality.

MQ-135 Wiring and Usage:

– Power: Connect the VCC pin to a 5V power supply and GND to ground.
– Analog Output: Connect the AOUT pin to an analog input pin on a microcontroller (e.g., Arduino) to read the gas concentration.
– Digital Output: Connect the DOUT pin to a digital input pin on a microcontroller for threshold-based detection. The threshold can be adjusted using the onboard potentiometer.

MQ-135 Important Points:

– Calibration: The sensor needs to be calibrated in a clean air environment for accurate readings.
– Ventilation: Ensure proper ventilation around the sensor to avoid false readings due to stagnant air.
– Safety: While the MQ-135 can detect a range of gases, it should not be used as the sole safety device in environments where gas detection is critical.

In summary, the MQ-135 is a versatile air quality sensor that can be used in various applications to monitor harmful gas concentrations, ensuring safer and healthier environments. It is compatible with Arduino.

Click here to access datasheet.