The time has come to brush off our MQTT and MCU-knowledge. We have spent some time setting up a basic communication between two MCUs. We believe that a good first step to setting up the communication is to do so without involving NodeRed, but directly via the MQTT-server. 

One MCU was connected to four buttons, and the other MCU had an LED-strip. The buttons simulate radar sensors. Depending on the button that is being pressed, the LED-strip lights up in a preset color-combination.

The process involved a lot of brushing off knowledge, looking back at old exercises and Project 2 scripts. Finally, we got there.

Next up: Involve NodeRed in the communication. Then, replace the buttons with the radars.