MQ-5 Gas Sensor Module for LPG, Natural Gas, and Coal Gas

Product Overview

The MQ-5 Gas Sensor Module is a precision electro-chemical detection board designed to monitor ambient concentrations of Liquefied Petroleum Gas (LPG), natural gas, methane (CH4), propane (C3H8), and coal gas. Utilizing a micro-ceramic tube with a tin dioxide (SnO2) semiconductor sensitive layer, the sensor exhibits low electrical conductivity in clean atmospheric conditions. When target combustible gases diffuse into the sensing element, the surface resistivity decreases proportionally to the gas concentration, offering a reliable, low-latency safeguard for domestic and industrial gas safety systems.

Sensor Operation and Output Interface

This breakout module features dual signal outputs to simplify microcontroller integration. The Analog Output (AOUT) delivers a continuous voltage signal directly proportional to the detected gas concentration, allowing microcontrollers with Analog-to-Digital Converters (ADCs) to execute precise PPM calculations. The Digital Output (DOUT) is driven by an onboard high-precision LM393 voltage comparator, triggering a clean digital state change when gas levels exceed a user-defined limit. Users can fine-tune the switching threshold via an onboard potentiometer, while integrated LEDs provide real-time visual feedback for power and output activation status.

Technical Specifications and Electrical Characteristics

Operating across a supply voltage range of 2.5V to 5.0V DC, the MQ-5 module includes an internal heating element powered at approximately 800mW to maintain the optimal operating temperature for the SnO2 surface. The circuit consumes roughly 150mA during active thermal stabilization and gas sensing. It offers a broad detection range spanning 200 ppm to 10000 ppm for flammable gases. Signal routing is handled through a standard 4-pin header (VCC, GND, DO, AO), ensuring seamless hardware interfacing with microcontrollers such as Arduino, ESP32, STM32, and Raspberry Pi systems. Mechanical mounting is simplified via integrated 2.0mm screw holes.

Application Use-Cases and Implementation

Engineered for high stability, fast response, and rapid recovery, the MQ-5 module is ideal for residential gas leak alarms, industrial pipeline monitoring, smart home safety controllers, and environmental air quality equipment. To interface with a microcontroller system, link VCC to a 2.5V to 5.0V supply, GND to system ground, AOUT to an analog input pin for concentration logging, and DOUT to a digital interrupt pin for triggering immediate alarm relays or emergency gas shutoff valves.