MQ-135 AIR QUALITY GAS SENSOR MODULE

Description

The MQ-135 Air Quality Sensor Module is a semiconductor gas sensor used to detect and monitor air pollution and harmful gases in the environment. It is widely used in Arduino projects, IoT air quality systems, smart homes, and pollution monitoring devices.

It works by changing its internal resistance when exposed to different gases, giving both analog and digital outputs for measurement and threshold detection.

Key Features

• Detects air quality and harmful gases in the surroundings
• Sensitive to NH₃, NOx, CO₂, alcohol, benzene, smoke
• Analog output for gas level measurement (0–5V)
• Digital output for threshold-based detection
• Built-in adjustable sensitivity (potentiometer)
• Fast response with stable performance after warm-up
• Compatible with Arduino, ESP32, Raspberry Pi
• Low-cost solution for air monitoring systems
• Suitable for indoor and outdoor air quality tracking
• Long-life semiconductor sensing element

Specifications

1. Product Type: Air Quality / Gas Sensor Module
2. Model: MQ-135
3. Operating Voltage: 5V DC
4. Current Consumption: ~150mA (heater element)
5. Sensing Element: SnO₂ (tin dioxide) semiconductor
6. Detectable Gases: NH₃, NOx, CO₂, alcohol, benzene, smoke
7. Output Type: Analog (AO) + Digital (DO)
8. Detection Range: ~10 – 1000 ppm (approx., gas dependent)
9. Warm-up Time: 1–3 minutes (stable use), up to 24–48 hours initial burn-in
10. Operating Temperature: -10°C to +50°C
11. Board Interface: VCC, GND, AO, DO (4-pin)
12. Comparator IC: LM393
13. Sensitivity Adjustment: Onboard potentiometer
14. Application: Air quality monitoring, gas leakage detection, IoT environmental systems, smart alarms