Description
The MQ-4 Natural Gas Methane Gas Sensor Module is a low-cost, highly sensitive semiconductor gas detection board designed for monitoring methane (CH₄) and natural gas in domestic, industrial, and portable gas detection applications. Built around the MQ-4 sensor with a tin dioxide (SnO₂) sensing layer, this module offers high sensitivity to methane while maintaining strong anti-interference capability against alcohol and other interfering gases . It is an ideal solution for household gas leak alarms, industrial combustible gas detectors, and portable gas detection instruments.
At the heart of the module is the MQ-4 sensor element, whose conductivity increases as the concentration of methane rises. In clean air, the sensor exhibits low conductivity; when exposed to methane or natural gas, its resistance drops, producing a measurable change in output . The module provides two independent outputs: an analog output (AO) that varies continuously with gas concentration for trend monitoring, and a digital output (DO) that switches when the concentration exceeds a user-adjustable threshold set by the onboard potentiometer . This dual-output design makes it suitable for both quantitative trend analysis and simple threshold-based alarm triggering.
The module operates from 5V DC with a typical current consumption of approximately 150mA . It is compatible with Arduino, ESP32, and other 5V microcontrollers; Raspberry Pi users require an external ADC. The board features a compact form factor and an onboard LED indicator that provides visual feedback for power and digital output status.
Important Note: The MQ-4 requires a significant preheat time for stable operation. New sensors should be powered on for not less than 48 hours in clean air before initial calibration . After each power-up, allow adequate time for the heater to stabilize. The sensor is not a calibrated industrial-grade detector and should not be used as a sole life-safety device. Its sensitivity degrades over time, and periodic replacement is recommended for critical applications. The sensor surface becomes hot during operation — avoid touching it. The module is not waterproof and should be kept dry.
Whether you are building a home gas leak alarm, an industrial methane detector, or an educational sensor project, the MQ-4 module provides a reliable, affordable solution for methane and natural gas detection.
Features
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MQ-4 SnO₂ semiconductor sensor — High sensitivity to methane (CH₄) and natural gas
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Strong anti-interference — Resistant to alcohol and other interfering gases
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Dual output — Analog (AO) for concentration trends, Digital (DO) for threshold alarms
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Adjustable threshold — Onboard potentiometer sets the digital output trigger point
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Wide detection range — 300–10,000 ppm for methane
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5V operation — Compatible with Arduino, ESP32, and other 5V microcontrollers
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LED indicators — Power and digital output status feedback
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Compact form factor — 32 × 20mm PCB for easy integration
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Long lifespan — Specified for up to 10 years under proper operating conditions
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Wide application range — Household gas alarms, industrial detectors, portable instruments
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Sensor Model | MQ-4 (SnO₂ semiconductor) |
| 2 | Target Gas | Methane (CH₄), Natural Gas |
| 3 | Detection Range | 300 – 10,000 ppm (CH₄) |
| 4 | Operating Voltage | 5V DC |
| 5 | Heater Voltage | 5.0V ± 0.1V |
| 6 | Heater Power Consumption | ≤1W |
| 7 | Output Type | Analog (AO) + Digital (DO/TTL) |
| 8 | Preheat Time | Not less than 48 hours |
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