The MQ-135 is a high-sensitivity gas detector for monitoring air quality, CO₂, NH₃, NOₓ, benzene, and smoke. Ideal for indoor environmental monitoring, HVAC systems, and pollution detection, it outputs analog voltage proportional to gas concentration.
Key Benefits
✔ Multi-Gas Detection – Identifies CO₂, smoke, benzene, and toxic gases
✔ Precise Analog Output – Measure pollution levels quantitatively
✔ Preheating Circuit – Built-in heater for stable readings
✔ DIY-Friendly – Works with Arduino/ESP/RPi
Technical Specifications
Core Specifications
Target Gases: CO₂, NH₃, NOₓ, Benzene, Smoke
Operating Voltage: 5V ±0.1V
Output Signal: Analog (0–5V)
Detection Range: 10–1000 ppm (gas-dependent)
Response Time: <30s
Heater & Sensitivity
Heater Current: 150mA (during preheat)
Sensitivity Adjustment: Onboard potentiometer
Preheat Time: ≥24h (initial stabilization)
Physical Properties
Dimensions: 32mm × 22mm × 16mm
Sensor Type: Metal Oxide Semiconductor (MOS)
Pinout: 4-pin (VCC, GND, DO, AO)
Why Choose the MQ-135?
✔ All-in-One Pollution Detection – No separate sensors needed
✔ Cost-Effective – Cheaper than industrial gas detectors
✔ Wide Applications – From home to industrial use
Common Uses:
Smart air purifier controls
Factory air quality monitors
Office CO₂ level alerts
Forest fire detection systems
Pro Tips:
Calibrate in clean air before first use.
Limit continuous operation to extend lifespan (>48h use degrades accuracy).
Use with VOC sensors for comprehensive air analysis.
Package Includes:
1 × MQ-135 Gas Sensor Module