Monitor Your Environment with the MQ-135 Air Quality Sensor

Take control of your indoor air quality with the MQ-135 Air Quality Sensor Module. This versatile and low-cost sensor is designed to detect a wide range of harmful gases, making it an essential component for your Arduino, Raspberry Pi, or other electronic projects.

The MQ-135 is highly sensitive to ammonia (NH3), sulfides, and benzene vapor. It's also ideal for monitoring smoke, smog, and other air pollutants, providing both analog and digital signals to trigger alarms, control ventilation fans, or log data.

Key Features

• Dual Output Signals: Provides both an AO (Analog Output), where voltage increases with gas concentration, and a DO (Digital Output), which goes low when the set concentration threshold is reached.
• Adjustable Sensitivity: An onboard potentiometer allows you to precisely calibrate the sensitivity and set the trigger threshold for the digital output.
• Clear Indicators: Equipped with a Power LED and a DO (TTL) output LED that lights up when the trigger threshold is crossed.
• Stable & Reliable: Features a long service life, reliable stability, and rapid response and recovery times for consistent performance.
• Easy Integration: The 4-pin header and mounting holes make it simple to integrate into your projects.

Applications

• DIY Air Quality Monitors
• Home or Factory Gas Leakage Alarms
• Automatic Ventilation Systems
• Environmental Monitoring Stations
• Smoke and Smog Detectors

Specifications

• Model: MQ-135
• Sensor Material: Tin Oxide (SnO2)
• Operating Voltage: DC 5V
• Current Consumption: 150mA
• Signal Outputs: AO (Analog), DO (Digital TTL)
• Analog Output (AO): 0.1V - 0.3V (in clean air), up to ~4V (at high concentration)
• Digital Output (DO): TTL 0/1 (0.1V / 5V)
• Dimensions: 32.4mm x 20.4mm
• Net Weight: 6.95g

How to Use & Wiring

Connecting the module is straightforward:

• VCC: Connect to 5V Power
• GND: Connect to Ground
• DO: Digital Output (Connect to any microcontroller digital I/O pin)
• AO: Analog Output (Connect to any microcontroller ADC pin)

Important Note: Upon power-up, the sensor requires a warm-up period of about 20 seconds for its readings to stabilize. It is normal for the sensor element to feel warm during operation.

Package Includes:

• 1 x MQ-135 Air Quality Sensor Module