MQ-135 Air Quality Sensor
by Winsen / generic
SKU: PSA-CMP-MQ135
No reviews yetTypical India street price
₹80–₹150
Broad air-quality / NH3 / benzene classroom sensor.
Interface: Analog + digital
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Concept
Same MOX family as MQ-2, tuned for “air quality” gases.
A little theory
Relative readings only unless you calibrate Rs/R0 in clean air. In the classroom, treat MQ-135 Air Quality Sensor as a intermediate part using Analog + digital. Typical India street price is about ₹80–₹150. Always verify voltage and pin labels on your exact module — silk screens vary across clones. Start with a datasheet or trusted learn guide, power the part correctly, share GND with the MCU, and test with a simple blink/read sketch before building the full project. Measure voltages with a multimeter when something fails, and keep actuator current off the MCU regulator.
How it works in a project
Preheat, read analog, compare to baseline.
Classroom & project use
- Classroom AQI demo
- Ventilation reminder
- Sensors classroom demo
Buying in India
Precautions
- Not a medical/industrial instrument
- Check 3.3 V MCU compatibility before connecting signal pins
Specifications
| Heater | 5V |
| Output | AO + DO |
| Category | Sensors |
| Difficulty | Intermediate |
| Voltage | 5V |
| Interface | Analog + digital |
Pinout
VCC | GND | AO (and DO if comparator module)
