MQ-135 Air Quality Sensor

The MQ-135 Air Quality Sensor is an electronic gas sensor used to detect air pollution and measure the quality of air. It is sensitive to various gases such as ammonia, nitrogen oxides, alcohol, benzene, smoke, and carbon dioxide-related gases. The sensor works by changing its internal resistance when exposed to different gas concentrations, which can be read as an analog or digital signal.

• Sensor Type: Semiconductor gas sensor
• Model: MQ-135
• Operating Voltage: 5V DC
• Heating Voltage: 5V (internal heater required)
• Detection Gases: NH₃ (ammonia), NOx, alcohol, benzene, smoke, CO₂ (approx. equivalent)
• Detection Range: ~10 ppm to 1000+ ppm (varies by gas)
• Output Type: Analog (AO) and Digital (DO)