1. Introduction The MH Series “Flying Fish” (also known as MH-Z or simply MH breakout boards) are a family of compact, easy-to-use sensor modules designed primarily for gas detection using MQ-series gas sensors (e.g., MQ-2, MQ-3, MQ-5, MQ-7, MQ-9, MQ-135, etc.). The “Flying Fish” nickname refers to the board’s distinctive shape and the 3-pin “Fish” connector (GND, VCC, OUT) commonly used in hobbyist and educational kits.
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These modules are popular in , ESP8266 , ESP32 , and Raspberry Pi projects for air quality monitoring, breathalyzers, LPG leakage detectors, and industrial gas sensing. 2. Key Features | Feature | Description | |---------|-------------| | Sensor Type | Metal oxide semiconductor (MOS) – MQ series | | Operating Voltage | 5V DC (some models support 3.3V logic via regulator) | | Output Type | Analog voltage (0–5V) + Digital TTL logic (TTL high/low) | | Heater Power | ~800 mW (depends on MQ sensor) | | Preheat Time | 20–60 seconds (sensitive after 24h for full calibration) | | Connector | 3-pin “Flying Fish” connector (GND, VCC, OUT) | | Adjustable Sensitivity | Yes, via onboard potentiometer | | Onboard LED | Power LED (red) + Digital trigger LED (green/red) | | Dimensions | Approx. 32mm × 22mm × 22mm | 3. Pinout (Standard 3-Pin “Flying Fish” Connector) Most MH MQ modules use the following pinout for the white 3-pin connector (JST XH 2.54mm):