MQ-135 5V air quality sensor detects CO2, ammonia NH3, smoke, benzene

MQ-135 5V air quality sensor

The MQ-135 air quality sensor module is an advanced tool for monitoring the presence of atmospheric pollutants such as benzene, ammonia (NH3), and carbon dioxide (CO2). The module includes a potentiometer for adjusting the sensitivity threshold. Exceeding the set threshold switches the output signal from high to low and activates the indicator LED. The sensor works well as part of a home air quality monitoring station for tracking pollutant levels in real time. The module is compatible with popular platforms: Arduino, ESP8266, ESP32, and Raspberry Pi.

Key technical specifications

• Supply voltage: 5V
• Detectable substances: alcohols, ammonia, benzene, smoke, CO2
• Operating temperature: -10°C to 45°C
• Output type: digital and analog
• Module dimensions: 30 mm x 20 mm

Example applications

• Home air quality monitoring stations
• Building ventilation and air purification systems
• Educational projects and microcontroller-based prototypes
• Alarm systems that react when gas concentration limits are exceeded
• Monitoring conditions in farm and office spaces

Benefits

• Broad range of pollutants detected in one module
• Smooth adjustment of the trigger threshold with the built-in potentiometer
• Easy integration with 5V systems and popular microcontrollers
• Dual signal output for easier reading and data analysis
• Compact size for mounting in small project enclosures