Introduction
The ESP32 is one of the most popular microcontrollers for IoT projects. Combined with MQTT — a lightweight messaging protocol designed for constrained devices — you can build powerful connected applications with ease.
What You'll Need
- ESP32 development board
- Arduino IDE or PlatformIO
- A free HiveMQ or Mosquitto MQTT broker account
Step 1: Set Up Your Development Environment
Install the Arduino IDE and add ESP32 board support via the board manager. Install the PubSubClient library for MQTT.
Step 2: Connect to Wi-Fi
Use the WiFi.h library to connect your ESP32 to your local network. Always store credentials in a separate config file.
Step 3: Publish to MQTT
Use PubSubClient to connect to your broker and publish a JSON payload with your sensor readings every 5 seconds.
Conclusion
You now have a working ESP32 publishing data over MQTT. Next, try subscribing to a topic to receive commands from the cloud!