Description
The MQ-8 Hydrogen Gas Sensor Module is a low-cost, highly sensitive semiconductor gas detection board designed for monitoring hydrogen (H₂) and hydrogen-containing gases such as city gas (coal gas) in domestic, industrial, and portable gas detection applications. Built around the MQ-8 sensor with a tin dioxide (SnO₂) sensing layer, this module offers high sensitivity to hydrogen while maintaining good anti-interference capability against alcohol, cooking fumes, LPG, and CO . It is an ideal solution for household hydrogen leak alarms, industrial flammable gas detectors, and portable safety instruments.
At the heart of the module is the MQ-8 sensor element, whose conductivity increases as the concentration of hydrogen rises. In clean air, the sensor exhibits low conductivity; when exposed to hydrogen, 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 .
The module operates from 5V DC with a typical working current of less than 150mA . It is compatible with Arduino, ESP32, and other 5V microcontrollers; Raspberry Pi users require an external ADC. The board features a compact 22 × 38mm form factor with mounting holes, and an onboard LED indicator provides visual feedback for power and digital output status .
Important Note: The MQ-8 requires a significant preheat time for stable operation. The sensor should be powered on for more than 48 hours in clean air before initial calibration for accurate readings . After each power-up, allow at least 30 minutes 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. Avoid exposure to corrosive gases, water, and overvoltage, which can damage the sensing element .
Whether you are building a home hydrogen leak alarm, an industrial H₂ detector, or an educational sensor project, the MQ-8 module provides a reliable, affordable solution for hydrogen gas detection.
Features
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MQ-8 SnO₂ semiconductor sensor — High sensitivity to hydrogen (H₂) and city gas
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Good anti-interference — Resistant to alcohol, cooking fumes, LPG, and CO
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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 — 100–1000 ppm for hydrogen (some variants up to 10,000 ppm)
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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 — 22 × 38mm PCB with mounting holes
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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-8 (SnO₂ semiconductor) |
| 2 | Target Gas | Hydrogen (H₂), City Gas |
| 3 | Detection Range | 100 – 1000 ppm (H₂) |
| 4 | Operating Voltage | 5V DC |
| 5 | Heater Voltage | 5.0V ± 0.1V AC or DC |
| 6 | Heater Power Consumption | ≤950mW |
| 7 | Output Type | Analog (AO) + Digital (DO/TTL) |
| 8 | Preheat Time | More than 48 hours |
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