Description
The MQ-8 Hydrogen Gas Sensor is a low-cost, highly sensitive semiconductor gas detection module 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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