MQ-2 Smoke Gas Sensor Detector Module

The MQ-2 Smoke Gas Sensor Detector Module is a highly reliable semiconductor-based gas sensing module designed to detect the presence of smoke and various combustible gases in the surrounding environment. It is capable of sensing gases such as LPG (Liquefied Petroleum Gas), methane (CH₄), propane (C₃H₈), hydrogen (H₂), butane, and smoke, making it an ideal solution for gas leakage detection, fire safety systems, industrial monitoring, and home automation applications.

The module is built around the popular MQ-2 gas sensor, which uses a tin dioxide (SnO₂) sensing element. Under clean air conditions, the sensor has high electrical resistance. When combustible gases or smoke are present, the resistance of the sensing element changes proportionally to the gas concentration. This change is converted into electrical signals that can be easily processed by microcontrollers such as Arduino, ESP8266, ESP32, Raspberry Pi, STM32, PIC, AVR, and other embedded development boards.

The MQ-2 module provides both analog (AO) and digital (DO) outputs. The analog output delivers a variable voltage corresponding to the concentration of the detected gas, allowing precise gas level measurement through an analog input pin. The digital output provides a HIGH or LOW signal when the gas concentration exceeds a preset threshold. This threshold can be easily adjusted using the onboard potentiometer, making the module suitable for different environmental conditions and applications.

The module operates from a 5V DC power supply and includes onboard power and output indicator LEDs for convenient monitoring. The built-in comparator circuit ensures stable digital output, while the adjustable sensitivity allows users to fine-tune the detection threshold according to specific project requirements.

The MQ-2 Smoke Gas Sensor Detector Module is widely used in gas leakage alarm systems, smoke detectors, fire detection systems, industrial safety equipment, smart home automation, environmental monitoring systems, and educational electronics projects. It offers a simple interface, reliable performance, and excellent sensitivity, making it one of the most commonly used gas sensors for hobbyists, students, and professional engineers.

Working Principle

The MQ-2 sensor operates using a semiconductor tin dioxide (SnO₂) sensing element.

• In clean air, the sensor has relatively high electrical resistance.

• When combustible gases or smoke are present, the resistance of the sensing element decreases.

• The onboard circuitry converts this resistance change into analog and digital electrical signals.

• The analog output varies according to gas concentration.

• The digital output switches when the gas level exceeds the user-adjustable threshold.

Key Features

• Detects smoke and multiple combustible gases

• Sensitive to LPG, methane, propane, hydrogen, butane, and smoke

• Analog output for gas concentration measurement

• Digital output for threshold detection

• Adjustable sensitivity using onboard potentiometer

• Fast response and recovery time

• High sensitivity and stable performance

• Operating voltage: 5V DC

• Built-in comparator circuit

• LED indicators for power and output status

• Easy interface with Arduino, ESP32, ESP8266, Raspberry Pi, AVR, PIC, STM32, and other microcontrollers

• Durable and compact PCB design

• Suitable for continuous gas monitoring

Applications

The MQ-2 Smoke Gas Sensor Detector Module is commonly used in:

• Gas leakage detection systems

• Smoke detection systems

• Fire alarm systems

• LPG leakage monitoring

• Methane gas detection

• Hydrogen leak detection

• Home automation systems

• Industrial safety monitoring

• Smart building security

• Environmental monitoring

• Arduino projects

• ESP32 and ESP8266 projects

• Raspberry Pi applications

• Robotics projects

• Educational electronics experiments

• Embedded system development

Specifications

• Product Type: Smoke and Gas Sensor Module

• Sensor Model: MQ-2

• Operating Voltage: 5V DC

• Detection Gases: Smoke, LPG, Methane, Propane, Hydrogen, Butane

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

• Sensitivity Adjustment: Onboard Potentiometer

• Indicator LEDs: Power LED and Output LED

• Mounting: PCB Module

• Interface: Standard Pin Header