Usually used to identify beacons within an iBeacon group. Defaults to 61958. Setting Up ¶ First, you'll need to set up the configuration for ESPHome. Just copy the configuration above and change the UUID to something unique. For example, you can copy this randomly generated UUID: Then, just compile and flash the ESP32. The ESP32 is subscribed to the esp32/output topic to receive the messages published on that topic by the Node-RED application. Then, accordingly to the received message, it turns the LED on or off. Subscribing to MQTT topics. In the reconnect() function, you can subscribe to MQTT topics. In this case, the ESP32 is only subscribed to the esp32.