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Semiconductor-based, multi-gas, affordable solution for graduation project “electronic nose”.
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Module Introduction
The MQ series is a semiconductor gas sensor,multi-gas selectable (MQ-2 for smoke, MQ-5 for combustible gases, MQ-135 for air quality, etc.), powered by 5V, with analog + TTL dual output, an affordable solution for graduation project “electronic nose”.
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Module Principle
SnO₂ semiconductor, gas adsorption → resistance decreases → analog voltage ↑, digital output adjustable threshold, no calibration needed for “alarm/no alarm”.
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Core Parameter Table
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Pin Table
Note: DO threshold is adjusted with a potentiometer; AO 0-5 V directly to ADC.
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Usage Steps
1. Power on with 5 V, preheat for 5 min;
2. ADC reads AO → voltage → Rs/R0 estimates concentration;
3. DO high level → gas exceeds standard → interrupt alarm.
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Graduation Project Scenarios
– Smoke alarm, >1000 ppm buzzer;
– Combustible gas leak, DO interrupt SMS;
– Air quality display, MQ-135 → CO₂ estimation;
– Electronic nose, multi-MQ array → PCA recognition.
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Precautions
① Semiconductor-based, affected by temperature and humidity, requires temperature and humidity compensation;
② Preheat for 24 hours for first use, daily 5 min;
③ Adjust threshold potentiometer, do not turn all the way at once;
④ Lifespan 2-3 years, for accuracy requirements ±10 ppm please switch to NDIR.