MQ-3 Gas Sensor Module (High-Sensitivity Alcohol Detection Board)
Deploy high-precision ethanol vapor tracking and threshold monitoring with the industrial-grade MQ-3 Gas Sensor Module. Precision-engineered to isolate and detect alcohol concentrations in the air, this module utilizes a high-performance tin dioxide semiconductor sensing layer that experiences low conductivity in clean air but spikes sharply when alcohol vapors are introduced.
The MQ-3 sensor is heavily optimized to detect alcohol fumes and ethanol gas with exceptional speed, making it the definitive hardware choice for breathalyzer prototypes, laboratory safety equipment, and industrial distillery monitors. It serves as an essential safety node for smart vehicle locking systems, portable diagnostic devices, and environmental monitoring grids.
Key Features
Alcohol Specific Tuning: Highly sensitive to alcohol vapor (ethanol) while maintaining very low cross-sensitivity to standard cooking smoke, carbon monoxide, or general combustible gases.
Dual Output Architecture: Built with both a Digital Output for instantaneous high/low safety alarm triggers and an Analog Output for real-time concentration mapping.
Adjustable Alarm Threshold: Features an onboard multi-turn potentiometer, allowing you to finely adjust the digital trigger point to match your specific clean-air background baseline.
Onboard Voltage Comparator: Assembled with a highly stable comparator integrated circuit, ensuring clean, sharp digital square waves that eliminate false triggers.
Explosion-Proof Stainless Steel Mesh: Designed with a dual-layer stainless steel mesh cover that protects the internal heated filament while maintaining safe airflow into the sensor chamber.
Real-Time LED Status Monitoring: Equipped with two independent indicators—one for central power tracking and another that lights up instantly when alcohol vapors pass your preset limit.
Technical Specifications
Feature | Specification |
Sensor Type | Semiconductor Gas Sensor (MQ-3) |
Target Gas | Alcohol Vapor, Ethanol Gas |
Operating Voltage | 5V DC Nominal |
Operating Current | Approx. 150 mA |
Detection Concentration Range | 0.05 mg/L to 10 mg/L Alcohol (or 25 to 500 ppm) |
Output Type | Dual Output: Analog Output + Digital Output |
Active Logic State | Digital Output drops LOW (0V) when alcohol thresholds are crossed |
Mounting Layout | Pre-drilled screw holes for secure panel or chassis attachment |
Board Dimensions | 32 mm x 20 mm x 22 mm |
Hardware Wiring & Pin Mapping
The module breaks out a 4-pin interface that maps directly to standard microcontrollers like Arduino, ESP32, STM32, and Raspberry Pi:
VCC: Connects to a stable +5V DC power supply rail. (Requires a dedicated 5V source to correctly power the internal heating element).
GND: System Ground Reference.
DO (Digital Output): Outputs a stable High/Low logic level. Connect this straight to a digital input or hardware interrupt pin. It stays HIGH in standard conditions and drops LOW when alcohol vapors cross your preset threshold.
AO (Analog Output): Outputs a varying voltage signal corresponding directly to the concentration of alcohol vapor in the air. Connect this to an analog pin to process exact concentration calculations and blood alcohol concentration estimations.
Common Applications
DIY Breathalyzer Devices: Build custom, portable digital alcohol breath testers to calculate and display vapor levels on LCD screens.
Smart Vehicle Ignition Interlocks: Integrate with automotive ignition relays to prevent a car engine from starting if the driver’s breath sample registers alcohol presence.
Distillery & Winery Telemetry: Monitor processing areas and storage facilities to trace vapor escape points or ambient ventilation needs during fermentation.
Laboratory Safety Systems: Deploy near chemical storage cabinets to check for evaporating industrial alcohol solvents or open container leaks.
💡 Operating Tip: The MQ-3 sensor requires a "Preheat / Burn-in" period before it can output accurate readings. After powering the module on for the very first time, let it sit powered up for 24 to 48 hours to balance the internal chemical sensing element. For subsequent uses, allow 1 to 2 minutes of warm-up time until the heater stabilizes. The module will become warm to the touch during normal operation—this is perfectly normal behavior for the internal heater loop.
Package Includes:
1 x MQ-3 Alcohol Gas Sensor Module (4-Pin Breakout Board)