ESP8266-Based Alcohol Detection with Live IoT Dashboard

Build an alcohol-vapour monitoring prototype using the MQ-3 sensor and NodeMCU ESP8266, and visualize readings KiwisIoT on dashboard

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ESP8266-Based Alcohol Detection with Live IoT Dashboard

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

DFRobot Gravity: Analog Alcohol Sensor (MQ3) For Arduino

Jumper wires (generic)

Software apps and online services

Kiwistron KiwisIoT

Arduino IDE

Story

Project Overview

In this project, I developed an IoT-based alcohol vapour monitoring system using the MQ-3 alcohol sensor, NodeMCU ESP8266, and KiwisIoT. The system reads the sensor's analog output, connects to Wi-Fi, and sends the readings to a cloud dashboard for remote monitoring.

The main objective is to demonstrate how a gas sensor and an IoT platform can work together to collect, transmit, and visualize sensor data in real time.

How It Works

The MQ-3 is a semiconductor gas sensor designed to respond to alcohol vapour in the surrounding air. When the sensor is exposed to alcohol vapour, its electrical characteristics change, producing a corresponding output signal.

The NodeMCU ESP8266 reads this signal through its analog input. It then transmits the raw sensor reading to KiwisIoT over Wi-Fi, where a dashboard widget can display the changing values.

The complete data flow is:

MQ-3 Sensor → NodeMCU ESP8266 → Wi-Fi → KiwisIoT Dashboard

Circuit Connections

Connect the sensor module to the NodeMCU as follows:

VCC: Connect to a suitable 5V supply if required by the MQ-3 module.
GND: Connect to NodeMCU GND.
AO: Connect to the NodeMCU A0 analog input after confirming the voltage is within the board's permitted input range.

The MQ-3 heater commonly requires approximately 5V. Do not assume that the sensor's analog output is safe for the ESP8266. Check the module's output voltage and your particular NodeMCU board's A0 input specification. Use a suitable voltage divider or signal-conditioning circuit when necessary.

KiwisIoT Dashboard Setup

Create or open a device dashboard in KiwisIoT and add a suitable numeric or gauge widget for the sensor reading.

Configure the widget to receive data on Channel 1. Make sure the channel used in the Arduino sketch matches the channel configured in the dashboard.

The dashboard will display the sensor's raw analog reading. Higher or lower values may indicate a change in the sensor's response, depending on the module and circuit.

Arduino Code

Install the ESP8266 board package and the KiwisIoT library before uploading the sketch. Replace the Wi-Fi credentials and Topic ID with your own configuration.

Upload and Test

Open the sketch in Arduino IDE and select the correct ESP8266 board and COM port. Upload the program and open the Serial Monitor at 115200 baud

Allow the MQ-3 sensor to warm up according to its datasheet and module instructions. The sensor may require an extended initial conditioning period before its readings become more stable.

Once the board connects to Wi-Fi, observe the readings in the Serial Monitor and check whether the KiwisIoT dashboard updates on Channel 1. Changes in the surrounding environment can affect the values, so test in a controlled, well-ventilated setting.

Applications

This educational prototype demonstrates concepts that can be extended to:

Alcohol-vapour monitoring demonstrations.
IoT sensor-data visualization.
Embedded systems and Wi-Fi communication experiments.
Remote observation of gas-sensor responses.
Student projects involving cloud dashboards and sensor analytics.

Conclusion

This project demonstrates a simple way to connect an MQ-3 alcohol sensor to an IoT dashboard using NodeMCU ESP8266 and KiwisIoT. By reading the sensor output and transmitting it over Wi-Fi, the system makes sensor changes easier to observe remotely.

It also provides practical experience with analog sensing, microcontroller programming, Wi-Fi connectivity, and cloud-based data visualization.

Important safety note: This prototype is for educational alcohol-vapour monitoring only. Raw MQ-3 readings are not calibrated alcohol concentration measurements and must not be used to determine blood alcohol content, intoxication, or fitness to drive. The project is not a certified breathalyser or a substitute for professional safety equipment.

Explore More KiwisIoT Projects

For more ESP8266, sensor-monitoring, and IoT dashboard projects, visit the KiwisIoT Projects repository:

https://github.com/Kiwistron/KiwisIoT-Projects/

Schematics

Untitled file

#include <KiwisIoT.h>

const int alcoholSensorPin = A0;

const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";
const char* topicId = "YOUR_TOPIC_ID";

int alcoholReading = 0;

void setup() {
  Serial.begin(115200);

  pinMode(alcoholSensorPin, INPUT);

  // Initialize KiwisIoT using your configured credentials.
  kiwisiot.begin(ssid, password, topicId);

  Serial.println("Alcohol Vapour Monitoring Started");
}

void loop() {
  kiwisiot.run();

  alcoholReading = analogRead(alcoholSensorPin);

  Serial.print("Raw Sensor Reading: ");
  Serial.println(alcoholReading);

  // Send the raw reading to dashboard Channel 1.
  kiwisiot.send("1", alcoholReading);

  delay(2000);
}