Sensor
MQ-135 air quality sensor
Sniffs out CO₂-equivalent gases, smoke and general bad air.
Pinout
- VCCpower (5 V)
- AOUTanalog
- GNDground
Bench notes
Let it burn in for 24 h before trusting the numbers — the heater needs to settle.
- Typical price
- $2.20
- Libraries
- none needed
- Prompt keywords
- air, gas, co2, quality