MQ-3 Gas Sensor Module For Benzine, CH4, Hexane, LPG, CO Detector Module
MQ-3 Gas Sensor Module
Alcohol & Gas Detection Semiconductor Gas Sensor Safety Monitoring
The MQ-3 Gas Sensor Module is a semiconductor-based gas sensor designed to detect alcohol vapors and various flammable gases such as benzene, methane (CH), hexane, LPG, and carbon monoxide (CO). It is widely used in breath alcohol analyzers, gas leakage detection systems, and safety monitoring devices.
The sensor operates by detecting changes in resistance of the sensing material when exposed to different gas concentrations.
Infographic Overview
Basic Specifications
Feature | Details |
Sensor Type | Semiconductor Gas Sensor |
Operating Voltage | 5V |
Output Type | Analog (A0) &am |
Preheat Time | ~20 seconds (recommended longer for accuracy) |
Sensitivity Adjustment | Yes (Potentiometer) |
Main Components
Component | Description |
MQ-3 Gas Sensor Element | Detects alcohol and gases |
Heating Coil | Maintains sensor operating temperature |
Comparator IC (LM393) | Converts analog signal to digital output |
Sensitivity Potentiometer | Adjusts detection threshold |
Indicator LEDs | Shows power and detection status |
Pin Configuration
Pin | Function |
VCC | Power s/td |
A0 | Analog output |
D0 | Digital output |
Working Principle
The sensor works based on semiconductor gas sensing technology.
Step-by-Step Operation
1 The heater element warms the sensing material.2 Gas molecules interact with the tin dioxide (SnO) sensing layer.3 The sensor's electrical resistance changes depending on gas concentration.4 The module converts this change into analog voltage output.5 The comparator triggers a digital output when gas level exceeds the threshold.
Sensor Detection Diagram
Gas Molecules'MQ-3 Sensor Element(Heated SnO Layer)Res
Gas Type | Detection Capability |
Alcohol Vapors | High sensitivity |
Benzene | Detectable |
LPG | Detectable |
Methane (CH) | Detectable |
Hexane | Detectable |
Carbon Monoxide | Detectable (lower sensitivity) |
Common Applications
Breath alcohol detection systems Gas leakage detection Industrial safety monitoring Air quality monitoring projects Smart IoT gas alarm systems
Compatible Microcontrollers
The module works easily with:
Arduino Uno
Arduino Nano
MQ-3 vs MQ-2 Gas Sensor
Feature | MQ-3 | MQ-2 |
Primary Detection | Alcohol | LPG, Smoke |
Sensitivity | Alcohol vapors | Flammable gases |
Applications | Breath analyzers | Gas leak detection |
Advantages
High sensitivity to alcohol vapors Adjustable detection threshold Analog and digital outputs available Easy microcontroller integration Low-cost and reliable sensor
Limitations
Requires warm-up time for accurate readings Sensitive to temperature and humidity Cross-sensitivity with multiple gases
Example DIY Project
Breath Alcohol Detector
Components
MQ-3 Gas Sensor Module
Working
Sensor detects alcohol vapor from breath Arduino processes analog signal System displays alcohol level and triggers alarm if limit exc