We will use the following topic name to publish the commands for an LED: home/control/leds/lednumber, where lednumber must be replaced with a unique numeric ID assigned to an LED wired to a board. For example, if we assign 1 as the ID for an LED that is wired to an Intel Joule 570x board, we will have to publish commands to the home/control/leds/1 topic and the code that runs on this board will subscribe to this topic to receive messages with commands and react to them.
Note that the topic name doesn't include details about the board and just focuses on the ID assigned to the LED. This is a specific requirement because it is necessary to make it possible to change the board to which the LEDs are wired without requiring edits in the client code. The client code doesn't have to know anything about the boards. Hence, the code that runs on the IoT boards must subscribe to all the topics for the different LEDs that they have wired. Of...
