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Arduino Alcohol Detector

This DIY electronics project showcases how to create a simple alcohol sniffing device using an Arduino and an MQ‑3 gas sensor. The system detects alcohol vapors in the environment—commonly used for breathalyzer-style applications—and provides immediate readings and visual feedback

Arduino Alcohol Detector
 
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Hardware Components

  • ARDUINO NANO V3 ATMEGA328P CH340G 5V BOARD TYPE-C

    X 1 fenxiang
  • Crowtail- Gas Sensor(MQ3) 2.0

    X 1
  • LED Diffused Round

    X 1 fenxiang
  • 12v SMD Buzzer

    X 1
  • PCB POLOS DOUBLE LAYER FR4 FIBER 10X15CM

    X 1 fenxiang

Tools, APP Software Used etc.

  • Arduino IDE

    Arduino IDE

    Arduino
  • Fritzing

Story

 

Project Overview

This DIY electronics project showcases how to create a simple alcohol sniffing device using an Arduino and an MQ‑3 gas sensor. The system detects alcohol vapors in the environment—commonly used for breathalyzer-style applications—and provides immediate readings and visual feedback.


 Objectives & Purpose

  • Design and build a breath alcohol detection system

  • Read alcohol levels via the MQ‑3 sensor

  • Display results to users through LEDs and serial output

  • Demonstrate sensor interfacing and basic data thresholding


 Key Components

Component Description
Arduino Uno/Nano Acts as the microcontroller base
MQ‑3 Gas Sensor Detection of alcohol vapor
LEDs Example: green for safe, red for alcohol alert
Buzzer (optional) Audible alarm when threshold crossed
Resistors For LED current limiting
Jumper Wires For connections
Breadboard Optional, for prototyping

 How the System Works

  1. MQ‑3 sensor measures alcohol concentration in breath via changes in analog output voltage.

  2. Arduino's analog input pin (e.g., A0) reads the sensor voltage.

  3. The code processes analog values:

    • If it exceeds a threshold → LED turns red + optional buzzer triggers.

    • Else → LED stays green.

  4. Serial Monitor output shows real-time sensor voltage values (for debugging and calibration).


 Wiring & Connections

  • MQ‑3 Sensor:

    • VCC → 5V

    • GND → GND

    • AOUT → Arduino A0

  • Green LED:

    • Anode → Arduino digital pin (e.g. D8) via resistor

    • Cathode → GND

  • Red LED (Alert):

    • Anode → Arduino digital pin (e.g. D9) via resistor

    • Cathode → GND

  • Buzzer (Optional):

    • One terminal → Arduino digital pin

    • Other terminal → GND


 Sample Arduino Sketch

cpp
const int sensorPin = A0; const int greenLED = 8; const int redLED = 9; const int buzzer = 10; // Optional const int threshold = 300; // Calibrate for your environment void setup() { Serial.begin(9600); pinMode(greenLED, OUTPUT); pinMode(redLED, OUTPUT); pinMode(buzzer, OUTPUT); digitalWrite(greenLED, HIGH); // default safe indication digitalWrite(redLED, LOW); } void loop() { int sensorValue = analogRead(sensorPin); Serial.println(sensorValue); if (sensorValue > threshold) { digitalWrite(redLED, HIGH); digitalWrite(greenLED, LOW); digitalWrite(buzzer, HIGH); // if included } else { digitalWrite(redLED, LOW); digitalWrite(greenLED, HIGH); digitalWrite(buzzer, LOW); } delay(500); }

???? Adjust threshold based on your calibration experiments (monitor serial output while testing with known ethanol sources).


 Applications & Extensions

  • Breathalyzer prototypes for educational purposes

  • Alcohol vapor detection in enclosed spaces

  • Calibration improvements using LCD/OLED displays

  • Bluetooth or Wi-Fi output for remote monitoring

  • Data logging to SD card or cloud services


 Key Learning Outcomes

  • Working with analog sensors and voltage-based thresholds

  • Interfacing the MQ‑3 gas sensor with Arduino

  • Using LEDs and buzzers for alerts

  • Calibrating sensors and interpreting analog data


 Safety & Calibration Notes

 

  • MQ‑3 sensors respond to both ethanol (alcohol) and certain volatile organic compounds—may give false positives if not calibrated

  • Always test in well-ventilated areas

  • Use small alcohol sources (e.g., diluted beverages) for testing—not direct ingestion

  • Be cautious with heating cycles and sensor warm-ups (usually requires several minutes to stabilize)

Code
  • CODE

    https://github.com/DharaniCreations/Arduino-Alcohol-Detector/blob/main/Alcohol%20Detector.ino
    View
Schematic and Layout
  • Diagram

    https://github.com/DharaniCreations/Arduino-Alcohol-Detector/blob/main/1_bb.jpg
    View

Arduino Alcohol Detector

This DIY electronics project showcases how to create a simple alcohol sniffing device using an Arduino and an MQ‑3 gas sensor. The system detects alcohol vapors in the environment—commonly used for breathalyzer-style applications—and provides immediate readings and visual feedback

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