01Why ESP32
The ESP32 is a dual-core Xtensa chip at 240 MHz with built-in Wi-Fi and Bluetooth. Cheap, power-efficient, programmable from the Arduino IDE or PlatformIO — it's the default modern IoT board.
02Connecting to Wi-Fi
Include <WiFi.h>, then call WiFi.begin(ssid, password) in setup(). Poll WiFi.status() until WL_CONNECTED. Print WiFi.localIP() to verify.
03Talking MQTT
Add the PubSubClient library. Configure broker host (e.g. test.mosquitto.org), call client.connect(), then publish topics like home/livingroom/temp every 10 seconds.
04Tiny web dashboard
Use ESPAsyncWebServer to host an HTML page directly from the chip. Push readings over WebSockets so the page updates live without polling.
05Power and deep sleep
- Active draw: 80–240 mA.
- Modem-sleep: ~15 mA.
- Deep sleep: 10 μA.
- Wake via timer or GPIO for battery projects.
06Production tips
- Always use OTA updates.
- Store secrets in NVS, not in source.
- Use static IPs or mDNS for discovery.
- Add a watchdog to recover from hangs.
