MQ-135 Air Quality Hazardous Gas Sensor Module

The MQ-135 Air Quality Hazardous Gas Sensor Module is a versatile and high-sensitivity gas detection sensor designed to measure a variety of harmful and toxic gases, including ammonia (NH₃), sulfur, benzene, smoke, carbon dioxide (CO₂), and other volatile organic compounds (VOCs). It is ideal for monitoring indoor air quality, pollution levels, and environmental health.

Built with a SnO₂ semiconductor sensing element, the MQ-135 exhibits low conductivity in clean air but increases its conductivity when exposed to hazardous gases. This property enables accurate gas concentration readings through analog voltage output, making it suitable for Arduino, ESP32, ESP8266, and Raspberry Pi platforms.

Operating at 5V DC, this sensor module provides both analog (AO) and digital (DO) outputs. The onboard LM393 comparator IC and adjustable potentiometer allow you to set custom thresholds for gas concentration, making it ideal for automatic alarm triggers, ventilation systems, or IoT-based real-time air quality monitoring.

The MQ-135 is known for its wide detection range, fast response, long life, and stable performance, making it one of the most popular sensors for environmental and air pollution detection projects. It can detect a mix of gases, providing an overall measure of air quality, which is highly useful in smart home air monitoring, industrial safety systems, and educational air sensor projects.

Purchase your MQ-135 Air Quality Hazardous Gas Sensor Module today from eleberric.com, Sri Lanka’s trusted source for Arduino sensors, IoT components, and embedded electronics.

Specification

• Model: MQ-135

• Operating Voltage: 5V DC

• Sensor Type: Semiconductor (SnO₂)

• Detection Range: 10 ppm – 1000 ppm (various gases)

• Detected Gases: NH₃, NOₓ, alcohol, benzene, smoke, CO₂, VOCs

• Output: Analog (AO) and Digital (DO)

• Preheat Time: 20 seconds (typical)

• Operating Temperature: -10°C to +50°C

• Dimensions: Approx. 32mm × 22mm × 27mm

• Weight: Approx. 25g

Key Features

• Detects multiple gases: NH₃, NOₓ, benzene, smoke, and CO₂

• High sensitivity and quick response time

• Dual output (Analog and Digital) for flexibility

• Adjustable sensitivity using onboard potentiometer

• LM393 comparator for stable digital output control

• Power and signal indicator LEDs

• Long lifespan and reliable operation

• Compatible with Arduino, ESP8266, ESP32, and Raspberry Pi

Applications

• Air quality and pollution monitoring

• Smart home air sensor systems

• Industrial environmental monitoring

• IoT-based real-time gas detection projects

• Indoor CO₂ and smoke detection

• Educational and research air sensing kits