Description
The MQ-4 Natural Gas Sensor is a low-cost, highly sensitive semiconductor gas detection module 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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