Arduino Projects

MQ-3 Sensor With Arduino

step by step guide MQ-3 Sensor interfacing with arduino


  • The MQ-3 sensor is widely used to detect alcohol vapour concentrations. By interfacing the MQ-3 sensor with an Arduino board and integrating a 16×2 LCD display, you can create a system that measures alcohol levels and displays the readings in a user-friendly format. This article provides a detailed step-by-step guide on how to set up the Arduino, connect the MQ-3 sensor, and display the alcohol readings on the LCD display.
  • Mq3 Sensor is most commonly used in the MQ Sensor Suitable for Detecting Alcohol, CH4, LPG And Co.
  • It is a metal oxide Semiconductor (MOS) Type Sensor Chemiresistors because the sensing is based on the resistance of the Sensing Material when exposed to alcohol.

MQ-3 Sensor 

  • The MQ-3 sensor is a gas sensor module widely used for detecting alcohol vapour concentrations. It is commonly employed in applications such as breathalyzers, alcohol detection systems, and safety devices. The sensor operates based on the principle of Metal Oxide Semiconductor (MOS) technology.
  • The MQ-3 sensor consists of a tin dioxide (SnO2) sensing element, which exhibits a change in electrical resistance when it comes into contact with alcohol vapours. The resistance of the sensing element decreases as the alcohol concentration increases.
  • In MQ-3 Sensor, the Analog Pin output Voltage provided by the sensor (A0 Pin) varies in proportion to the alcohol concentration. The higher the alcohol concentration in the air, the output voltage is High Whereas a lower concentration gives a lower Output Voltage.


  • High Sensitivity: The sensor has a high sensitivity to alcohol vapours, allowing it to detect even low concentrations accurately.
  • Fast Response Time: The MQ-3 sensor provides rapid response when exposed to alcohol vapours, making it suitable for real-time applications.
  • Analog Output: The sensor provides an analog output voltage that varies in proportion to the alcohol concentration in the environment.
  • Warm-Up Time: The MQ-3 sensor requires a warm-up time of around 24-48 hours to stabilize its readings. It is essential to allow the sensor to stabilize before obtaining accurate measurements.


  • Power requirements:- 5v
  • Current Consumption:- 140mA
  • Detecting Concentration:- 0.05-10mg/alcohol
  • Sensitivity S:-Rs(Air)/Rs(0.4mg/L Alcohol)>-5


  • Breathalyzer Project
  • Portable Alcohol Detector
  • Environmental Monitoring Equipment
  • Gas Level Monitoring

MQ-3 Sensor Pinout

MQ3 e1671646830779


Wiring Diagram MQ-3 Sensor With Arduino

Ds18B20 Sensor1111 3

PCB Design

PCB Design3

PCB Design3 1

PCB Design2

PCB Design1

Testing Of MQ-3 Sensor

Display MQ-3 Sensor Reading In Serial Monitor

MQ 31



Display MQ-3 Sensor Reading in LCD Display

Screenshot 2022 12 18 at 10.40.24 PM

Screenshot 2022 12 18 at 10.42.57 PM


Code with 16×2 LCD Display


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Interfacing the MQ-3 alcohol sensor with an Arduino board and a 16×2 LCD display allows you to create a system for monitoring alcohol vapour concentrations. By following this comprehensive guide, you can easily set up the hardware, upload the code, and visualize the alcohol readings on the LCD display. This project can find applications in breathalyzer devices, safety systems, and other scenarios where alcohol detection is required. Always exercise caution and adhere to legal regulations when working with alcohol-related measurements and devices.


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