Description
MQ-3 Alcohol Vapour Sensor Module
This module uses an MQ-3-family semiconductor sensor to respond to alcohol vapour, including ethanol vapour. It is intended for electronics experiments and prototypes. Its output depends on the sensor and breakout version, warm-up, calibration, temperature, humidity, airflow and other vapours present.
🔧 Product features
- Sensor type: semiconductor gas sensor (MQ-3 family)
- Target response: alcohol vapour / ethanol vapour
- Adjustable sensitivity: provided on some breakout versions; verify the supplied board
- Signal indicator: present on some board versions
- Output voltage generally changes with the sensor response; it is not a direct, calibrated alcohol concentration reading
For reference only, Winsen’s MQ-3B sensor documentation specifies a 25–500 ppm alcohol test range, a 5.0 V heater supply and preheating over 48 hours under its stated test conditions. The product is listed as MQ3, so confirm the exact sensor marking and module circuit before applying MQ-3B figures to the supplied unit.
⚙️ Operating notes
The sensing element is heated and needs time to stabilize. Readings from a new or recently powered sensor can drift; follow the actual sensor’s documentation, allow adequate warm-up and calibrate in controlled conditions. Different gases and vapours can affect the reading, so the output alone cannot reliably identify ethanol or determine a precise concentration.
🔌 Typical module connection
Connector labels vary by board. A common breakout provides VCC, GND, analog output (AO) and a threshold-comparator digital output (DO), but verify the actual markings. MQ-3-family heaters commonly require a stable 5 V supply and can draw substantial current compared with a microcontroller GPIO. Power the heater from an appropriate supply; share ground with the controller. Check the output level before connecting AO or DO to a 3.3 V-only input, and use level shifting or protection where necessary.
💡 Suitable uses
- Demonstrating gas-sensor response in a supervised lab
- Microcontroller analog-input and comparator projects
- Non-critical alcohol-vapour trend experiments
Important limitation: this module is not a breathalyzer, blood-alcohol estimator, medical instrument, legal evidence device, certified workplace monitor or life-safety alarm. Do not use it to assess intoxication, decide whether someone may drive, or protect people from hazardous vapours. Use certified instruments for those purposes and never test by deliberately creating a hazardous vapour concentration.
