MQ135-Air Quality Gas Sensor Module

The MQ135 Air Quality Gas Sensor Module is a versatile sensor designed to detect various gases and pollutants in the air. It’s widely used for air quality monitoring systems to measure the concentration of gases like ammonia (NH₃), nitrogen oxides (NOx), benzene (C₆H₆), alcohol, and smoke. This sensor is primarily used in indoor environments to monitor the air quality, ensuring it remains safe and healthy.

Key Features:

• Gas Detection: The MQ135 sensor is highly sensitive to a wide range of gases including ammonia (NH₃), nitrogen oxides (NOx), benzene (C₆H₆), alcohol (CH₃OH), smoke, and other volatile organic compounds (VOCs), which makes it ideal for air quality monitoring in both homes and industrial settings.
• Analog Output: The MQ135 sensor provides an analog output that varies in voltage according to the concentration of the gases in the air. This allows for continuous air quality monitoring and analysis.
• Digital Output: The sensor also offers a digital output that can be used to trigger alarms or activate control systems when the concentration of gases exceeds a preset threshold.
• Low Power Consumption: The MQ135 operates with minimal power, making it ideal for battery-powered applications or continuous monitoring in a wide range of devices.
• Preheating Time: Like other sensors in the MQ series, the MQ135 requires a warm-up period of about 1-2 minutes to stabilize and provide accurate readings.
• Wide Detection Range: The MQ135 can detect gas concentrations in the range of 10-1000 ppm (parts per million) for most of the gases it is sensitive to.

How It Works:

• The MQ135 operates based on a metal oxide semiconductor (MOS) that reacts with various gases when they come into contact with the sensor’s heated surface.
• The sensor has an internal heating element that needs to reach a specific temperature before it can function correctly. When gases such as ammonia or benzene interact with the sensor, they cause a chemical reaction that changes the electrical resistance of the sensor.
• The change in resistance is then translated into an output voltage that corresponds to the concentration of the detected gas. The output can be read by a microcontroller, such as Arduino or Raspberry Pi, for monitoring air quality in real-time.
• The analog output allows for a precise measurement of gas concentration, while the digital output can be used to trigger alarms or take corrective actions when gas levels exceed safe limits.

Applications:

• Air Quality Monitoring: The MQ135 sensor is ideal for indoor air quality monitoring in homes, offices, schools, and hospitals, where pollutants like benzene, ammonia, and smoke can negatively affect health.
• Industrial and Commercial Air Quality: It is used to monitor air quality in industrial and commercial spaces, particularly in places where VOCs, nitrogen oxides, and ammonia are produced.
• HVAC Systems: The MQ135 can be integrated into HVAC systems (heating, ventilation, and air conditioning) to continuously monitor and adjust air quality.
• Environmental Monitoring: It is used in environmental monitoring stations to track pollutants in the air, particularly in urban areas or near factories.
• Smart Home Applications: Can be used in smart home systems to ensure that the air inside homes remains healthy, activating air purifiers, fans, or ventilation systems when needed.
• Pollution Detection: Helps detect harmful levels of air pollution, triggering alarms to alert people to take action, such as closing windows or using air purifiers.