MQ-135 Gas Sensor Module For NH3, Alcohol, benzene, smoke , CO2 Detector Module

The MQ-135 Gas Sensor Module is a highly sensitive air quality monitoring sensor designed to detect a variety of harmful gases and pollutants in the environment. It can identify gases such as Ammonia (NH3), Alcohol, Benzene, Smoke, Carbon Dioxide (CO2), Sulfide compounds, and other airborne contaminants.

This sensor is widely used in indoor air quality monitoring, smart city applications, environmental monitoring systems, industrial safety solutions, and IoT-based pollution detection projects. The module includes an onboard LM393 comparator and adjustable sensitivity control, allowing users to customize detection thresholds according to their application requirements.

With support for both analog and digital outputs, the MQ-135 can be easily connected to Arduino, ESP32, ESP8266, Raspberry Pi, STM32, and other development boards.

Key Features
Detects NH3 (Ammonia), Alcohol, Benzene, Smoke, CO2, and harmful gases
Suitable for air quality monitoring applications
Analog and digital output support
Adjustable sensitivity threshold
High sensitivity and stable performance
Fast response and recovery time
Built-in LM393 comparator circuit
LED indicators for power and output status
Easy integration with microcontrollers
Ideal for IoT and environmental monitoring systems
Technical Specifications
Sensor Type: MQ-135 Gas Sensor
Operating Voltage: 5V DC
Output Type: Analog (AO) and Digital (DO)
Comparator IC: LM393
Detectable Gases:
Ammonia (NH3)
Alcohol Vapors
Benzene
Smoke
Carbon Dioxide (CO2)
Sulfides and Other Harmful Gases
Sensitivity: Adjustable via potentiometer
Preheating Time: Recommended before use
Response Time: Fast
Operating Temperature: -20°C to +50°C
Applications
Air Quality Monitoring

Measure indoor and outdoor air quality levels in real time.

Smart Home Automation

Monitor air pollution and trigger ventilation systems automatically.

Environmental Monitoring

Track harmful gases in industrial, commercial, and residential environments.

Industrial Safety Systems

Detect hazardous gas concentrations to improve workplace safety.

IoT-Based Monitoring

Integrate with ESP32 and ESP8266 for cloud-based pollution tracking and alerts.

Educational Projects

Learn about gas sensing technology and environmental monitoring systems.

Research and Development

Use in environmental studies, air quality analysis, and laboratory projects.

Pin Configuration
VCC – 5V Power Supply
GND – Ground
AO – Analog Output
DO – Digital Output
Package Includes
1 × MQ-135 Air Quality Gas Sensor Module
Why Choose the MQ-135 Gas Sensor Module?

The MQ-135 is one of the most popular sensors for air quality monitoring and environmental sensing applications. Its ability to detect multiple harmful gases, combined with adjustable sensitivity and simple interfacing, makes it an excellent choice for students, hobbyists, engineers, and IoT developers.

Whether you're building a smart air quality monitor, pollution detection system, industrial safety solution, or environmental research project, the MQ-135 provides reliable and cost-effective gas sensing performance.