📡 IoT-Based Environmental Monitoring System using ESP32 & MQTT

📌 Overview

This project is an IoT-based environmental monitoring system that uses an ESP32 microcontroller to collect real-time sensor data (temperature, humidity, and air quality) and transmit it to a remote server using the MQTT protocol.

The system is designed to demonstrate lightweight communication, real-time monitoring, and efficient data transmission in IoT applications.

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🚀 Features

• 🌡️ Temperature & Humidity monitoring using DHT11 sensor
• 🌫️ Air quality detection using analog gas sensor
• 📶 WiFi-enabled data transmission via ESP32
• 📡 MQTT protocol for lightweight communication
• 🔁 Real-time data publishing
• ⚡ Low power and efficient system

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🛠️ Technologies Used

• Hardware:

  • ESP32
  • DHT11 Sensor
  • Air Quality Sensor (Analog)
  • Breadboard & Jumper Wires

• Software:

  • Arduino IDE
  • Embedded C / Arduino Code
  • MQTT Protocol
  • WiFi Library

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🔌 Hardware Connections

DHT11 Sensor:

• VCC → 3.3V (ESP32)
• GND → GND
• Data → GPIO 4

Air Quality Sensor:

• VCC → 3.3V / 5V
• GND → GND
• Analog Output → GPIO 34

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⚙️ Working Principle

1. The ESP32 connects to a WiFi network.

2. Sensors (DHT11 and air sensor) collect environmental data.

3. The data is processed by the ESP32.

4. Using MQTT protocol:

   • ESP32 acts as a publisher
   • Sends data to an MQTT broker

5. The data can be viewed by any MQTT subscriber (dashboard/app).

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📡 MQTT Configuration

• Broker Address: (e.g., test.mosquitto.org or your own server)

• Port: 1883 (default MQTT port)

• Topics Used:

  • sensor/temperature
  • sensor/humidity
  • sensor/air_quality

Why Port 1883?

Port 1883 is the default port for MQTT communication without encryption, making it lightweight and ideal for IoT devices.

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📂 Project Structure

📁 IoT-ESP32-MQTT-Project
 ├── 📄 README.md
 ├── 📄 main.ino
 ├── 📄 config.h
 └── 📁 images (optional)

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🧑‍💻 Installation & Setup

1. Clone Repository

git clone https://github.com/your-username/your-repo-name.git
cd your-repo-name

2. Open in Arduino IDE

• Install ESP32 board support

• Install required libraries:

  • WiFi.h
  • PubSubClient.h
  • DHT.h

3. Configure WiFi & MQTT

Update:

const char* ssid = "YOUR_WIFI";
const char* password = "YOUR_PASSWORD";
const char* mqtt_server = "BROKER_ADDRESS";

4. Upload Code

• Select ESP32 board
• Upload code to ESP32

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📊 Output

• Sensor data is continuously sent to MQTT broker

• Can be visualized using:

  • MQTT Explorer
  • Node-RED Dashboard
  • Mobile apps

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🔄 Future Enhancements

• Add cloud integration (AWS / Firebase)
• Use secure MQTT (TLS – Port 8883)
• Add mobile/web dashboard
• Implement alerts (SMS/Email)
• Add more sensors

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🧠 Concepts Used

• IoT Architecture
• MQTT Protocol (Publisher–Subscriber model)
• Wireless Communication (WiFi)
• Embedded Systems

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📜 License

This project is open-source and available under the MIT License.

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🙌 Acknowledgment

This project was developed as part of an academic IoT learning experience.