Alcohol Detection Circuit Documentation

Summary

This document provides a detailed overview of an alcohol detection circuit. The circuit uses an MQ-3 alcohol sensor to detect alcohol levels. If the detected alcohol level exceeds a predefined threshold, the circuit triggers a relay, lights up an LED, and sounds a buzzer. The circuit is controlled by an Arduino UNO microcontroller.

Component List

1. Arduino UNO

   • Description: A microcontroller board based on the ATmega328P.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

2. MQ-3 Breakout

   • Description: An alcohol sensor module that provides both digital and analog outputs.
   • Pins: VCC, GND, DO, AO

3. Relay module 5v-30v

   • Description: A relay module that can be triggered by a low voltage signal to switch higher voltage loads.
   • Pins: common contact, normally open, normally closed, trigger, V-, V+

4. Buzzer

   • Description: A simple piezoelectric buzzer.
   • Pins: PIN, GND

5. LED: Two Pin (red)

   • Description: A standard red LED.
   • Pins: cathode, anode

Wiring Details

Arduino UNO

• GND connected to:

  • MQ-3 Breakout (GND)
  • Relay module 5v-30v (V-)
  • LED: Two Pin (red) (cathode)
  • Buzzer (GND)

• 5V connected to:

  • MQ-3 Breakout (VCC)
  • Relay module 5v-30v (V+)

• A0 connected to:

  • MQ-3 Breakout (AO)

• D8 connected to:

  • Relay module 5v-30v (trigger)

• D7 connected to:

  • Buzzer (PIN)

• D6 connected to:

  • LED: Two Pin (red) (anode)

MQ-3 Breakout

• GND connected to:

  • Arduino UNO (GND)

• VCC connected to:

  • Arduino UNO (5V)

• AO connected to:

  • Arduino UNO (A0)

Relay module 5v-30v

• V- connected to:

  • Arduino UNO (GND)

• V+ connected to:

  • Arduino UNO (5V)

• trigger connected to:

  • Arduino UNO (D8)

Buzzer

• GND connected to:

  • Arduino UNO (GND)

• PIN connected to:

  • Arduino UNO (D7)

LED: Two Pin (red)

• cathode connected to:

  • Arduino UNO (GND)

• anode connected to:

  • Arduino UNO (D6)

Documented Code

Arduino UNO Code

/*
 * Arduino Sketch for Alcohol Detection Circuit
 * This code reads the analog output from an MQ-3 alcohol sensor. If the alcohol
 * level exceeds a certain threshold, it triggers a relay, lights up an LED, and
 * sounds a buzzer.
 */

const int mq3Pin = A0; // MQ-3 sensor analog output connected to A0
const int relayPin = 8; // Relay module trigger pin connected to D8
const int buzzerPin = 7; // Buzzer pin connected to D7
const int ledPin = 6; // LED anode connected to D6
const int threshold = 300; // Threshold for alcohol level detection

void setup() {
  pinMode(relayPin, OUTPUT); // Set relay pin as output
  pinMode(buzzerPin, OUTPUT); // Set buzzer pin as output
  pinMode(ledPin, OUTPUT); // Set LED pin as output
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(mq3Pin); // Read the analog value from MQ-3
  Serial.println(sensorValue); // Print the sensor value to the serial monitor

  if (sensorValue > threshold) { // If alcohol level exceeds threshold
    digitalWrite(relayPin, HIGH); // Activate relay
    digitalWrite(buzzerPin, HIGH); // Sound buzzer
    digitalWrite(ledPin, HIGH); // Light up LED
  } else {
    digitalWrite(relayPin, LOW); // Deactivate relay
    digitalWrite(buzzerPin, LOW); // Turn off buzzer
    digitalWrite(ledPin, LOW); // Turn off LED
  }

  delay(500); // Wait for 500 milliseconds before next reading
}

MQ-3 Breakout Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

Relay module 5v-30v Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

Buzzer Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

This documentation provides a comprehensive overview of the alcohol detection circuit, including component descriptions, wiring details, and the code used to control the circuit.