Air Quality Sensor MQ135 Breakout

Operating Voltage: 2.5V to 5.0V
Power consumption: 150mA
Detect/Measure: NH3, Nox, CO2, Alcohol, Benzene, Smoke
Digital Output: 0V to 5V (TTL Logic ) @ 5V Vcc
Analog Output: 0-5V @ 5V Vcc
Dimensions: 22 x 38 mm / 0.9 x 1.5 inch

Monitor your indoor air quality and protect your health with this versatile MQ135 multi-gas sensor. Perfect for detecting dangerous CO2 levels, organic compounds (VOCs), ammonia, benzene, and smoke in homes, offices, and workshops. Whether you're building a smart home air quality system, creating environmental monitoring stations, or developing safety alert systems, this Arduino compatible sensor provides real-time gas detection with both analog and digital outputs. With our comprehensive documentation and library, you should be set to start working on your projects quickly!

This breakout board provides both digital (DO) and analog (AO) outputs for maximum flexibility. The digital output features an adjustable threshold via an onboard potentiometer, enabling custom trigger points for alarm systems and automated responses. The analog output delivers proportional voltage readings (0-5V) corresponding to gas concentration levels, perfect for data logging and monitoring applications. Operating at 5V with 150mA consumption, the sensor includes pre-heating circuitry for accurate readings and features mounting holes for permanent installations. The compact 22x38mm form fits easily into enclosures while providing environmental sensing capabilities.

Allow an initial pre–heating (48 hours first run and then each consecutive run 5 mins heat up time) period for optimal accuracy and stability. The MQ135 sensor provides relative gas concentration readings for trend monitoring and threshold detection. For precise measurements, calibration with known gas concentrations is recommended. Compatible with 5V microcontroller systems. Includes documentation, example code, and wiring diagrams to get your air quality monitoring project running. Perfect for smart home automation, environmental research, and safety monitoring applications.