MQ-135 Gas Sensor – Air Quality & Pollution Detection Module

(Detects NH3, NOx, Alcohol, Benzene, CO2 & Hazardous Gases)

🌫️ Smart Air Pollution Monitoring

The MQ-135 gas sensor is a highly sensitive module designed to detect harmful airborne pollutants like ammonia (NH3), nitrogen oxides (NOx), benzene, alcohol, and carbon dioxide (CO2). Ideal for air quality monitors, smart homes, and industrial safety systems.

🔑 Key Features

✔ Multi-Gas Detection – NH3, NOx, CO2, smoke, and VOCs
✔ Analog & Digital Output – Works with Arduino/Raspberry Pi
✔ Adjustable Sensitivity – Onboard potentiometer for threshold control
✔ Fast Response Time – <10s detection for most gases
✔ Heating Element – Pre-calibrated for accurate readings

🛠️ Applications

• Indoor Air Quality Monitors (For homes/offices)
• Industrial Leak Detection (Chemical plants, labs)
• Smart Ventilation Systems – Triggers air purifiers/fans
• Environmental Research – Pollution data logging
• DIY Safety Alarms – Toxic gas warning systems

📊 Technical Specifications

| Detection Range | 10-1000ppm (Varies by gas) |
| Operating Voltage | 5V DC |
| Output Signal | Analog (0-5V) & Digital (TTL) |
| Heater Consumption | ~800mW |
| Preheat Time | ≥24 hours (for stable readings) |
| Board Dimensions | 32×20mm |

📦 Package Includes

1× MQ-135 Gas Sensor Module
1× 4-pin female header (pre-soldered)

⚠️ Usage Notes

• Requires 24H preheating before first use
• Not for CO/flammable gas detection (Use MQ-2/MQ-9 instead)
• Avoid high humidity – Affects sensor accuracy

🔍 Why Choose This Sensor?

✅ Cost-Effective – Cheaper than professional air quality meters
✅ Arduino-Compatible – Sample codes readily available
✅ Widely Used – Trusted by makers worldwide