ESP32 MQTT Client

This project demonstrates how to use an ESP32 microcontroller to connect to a Wi-Fi network and communicate with an MQTT broker. It utilizes the WiFi and PubSubClient libraries to manage Wi-Fi connections and MQTT messaging.

Features

• Connects to a Wi-Fi network using provided credentials.
• Connects to an MQTT broker.
• Subscribes to an MQTT topic and listens for incoming messages.
• Publishes a message to an MQTT topic upon connection.

Prerequisites

Before running the code, ensure you have the following:

• An ESP32 microcontroller.
• The Arduino IDE installed with ESP32 support.
• The WiFi and PubSubClient libraries installed in the Arduino IDE.

Installation

1. Set Up the Arduino IDE for ESP32:

   • Follow the instructions on the ESP32 Arduino GitHub page to install the necessary board definitions.

2. Install Required Libraries:

   • Open the Arduino IDE and navigate to Sketch > Include Library > Manage Libraries.
   • Search for and install the PubSubClient library.

3. Configure the Code:

   • Open the provided code in the Arduino IDE.
   • Update the Wi-Fi credentials:

     const char* ssid = "your_wifi_ssid";
     const char* password = "your_wifi_password";

   • Update the MQTT broker credentials:

     IPAddress server(192, 168, 178, 30); // Replace with your broker's IP address

4. Upload the Code:

   • Connect your ESP32 to your computer.
   • Select the correct board and port in the Arduino IDE.
   • Upload the code to the ESP32.

Code Overview

Libraries

• WiFi.h: Manages the Wi-Fi connection.
• PubSubClient.h: Manages MQTT communication.

GPIOs

• LED: GPIO 2 is used for an LED indicator.

Functions

• callback(): Handles incoming MQTT messages.
• startWifi(): Connects the ESP32 to the Wi-Fi network.
• connectBroker(): Connects the ESP32 to the MQTT broker and subscribes to a topic.

MQTT Topics

• Publishing: The ESP32 publishes a message to the outTopic topic upon connection.
• Subscribing: The ESP32 subscribes to the test topic and processes incoming messages via the callback() function.

Usage

1. Start: After uploading the code, the ESP32 will connect to the specified Wi-Fi network.
2. Connect: It will then connect to the MQTT broker and publish a message to the outTopic.
3. Subscribe: The ESP32 will subscribe to the test topic and print incoming messages to the Serial Monitor.

Troubleshooting

• No Wi-Fi Connection: Ensure that the Wi-Fi credentials are correct and that the ESP32 is within range of the network.
• MQTT Connection Issues: Verify that the MQTT broker's IP address and credentials are correct and that the broker is reachable.

License

This project is licensed under the MIT License - see the LICENSE file for details.