MQ-4 Methane Gas Sensor Module
The MQ‑4 Methane Gas Sensor Module stands out as an accessible and effective way to detect combustible gases—primarily methane (CH₄) and natural gas—within a broad concentration range. It integrates the MX‑4 semiconductor sensor with an onboard LM393 comparator and a potentiometer, offering both precision analog output and threshold-based digital output.
The Analog Output (AO) provides a continuous voltage directly correlated with gas concentration, making it ideal for quantitative measurement and data logging. The Digital Output (DO) toggles state when the gas level breaches a set threshold, enabling immediate responses like alarms or safety shutoffs.
Powered by a standard 5V supply, this module is plug-and-play compatible with microcontrollers such as Arduino, ESP32, and Raspberry Pi. Built-in LEDs give real-time visual cues—one confirms power, while another indicates when the threshold has been exceeded—simplifying calibration and debugging.
Thanks to its compact size and easy wiring (four-pin interface), makers and professionals can effortlessly integrate it into systems like home safety alarms, industrial leak monitors, air-quality sensors, and educational kits. Its simple drive circuit, superb reliability, and long sensor life make the MQ‑4 module perfect for both citizen science and industrial designs.
Key Features
Detects methane, natural gas, and similar combustible gases
Offers both analog (AO) and digital (DO) outputs
Adjustable sensitivity via onboard potentiometer
Operates on 5 V logic—ideal for microcontrollers
LED indicators for power status and detection feedback
User-friendly 4-pin interface for easy integration
Product Specifications
| Specification | Details |
|---|---|
| Operating Voltage | 5 V DC |
| Sensor Type | MQ‑4 semiconductor gas sensor |
| Comparator | LM393 |
| Detection Range | 200–10,000 ppm (Methane / Natural Gas) |
| Heater Resistance | ~31 Ω ± 3 Ω (room temperature) – |
| Heating Power | ≤ 900 mW |
| Analog Output | Continuous voltage proportional to gas level |
| Digital Output | Switches on adjustable threshold exceedance |
| Sensitivity Control | Adjustable via potentiometer |
| Typical Current Draw | ~150 mA |
| Module Size | Compact, breadboard-friendly form factor |
Pin Configuration
| Pin | Label | Description |
|---|---|---|
| 1 | AO | Analog voltage output (detects gas concentration) |
| 2 | DO | Digital output (HIGH when gas threshold met) |
| 3 | GND | Ground |
| 4 | VCC | 5 V Power Supply |
Applications
Domestic natural gas or methane leak detection
Smoke and combustible gas alarms
Factory safety monitoring systems
Environmental air quality sensing
Educational electronics and safety projects
Smart home and IoT automation systems
