MQ-135 Air Quality Sensor
Sensors · Board: ESP32 · Day 32 of 100
The MQ-135 sniffs the air for harmful gases on the ESP32 and reports quality levels. Your own indoor air watchdog.
How it works
The MQ-135 reacts to several airborne contaminants, and the ESP32 converts its analog output into air-quality bands from fresh to poor. Because the sensor responds to multiple gases, calibration against clean air gives you a meaningful baseline to judge readings by.
What you'll learn
- Air quality indexing
- Multi-gas sensitivity
- Baseline calibration
- Analog band classification
Full project: code, wiring diagram & Wokwi simulation
The complete build guide lives in the original repo. Ours is a summary — the real thing is one click away.
Open full project on GitHub ↗Summary by SkillShop. Project by Kritish Mohapatra — code and diagrams belong to the original repo.
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