64 pixel RGB LED Display - Another Arduino Clone

Step 7: Application: talking to other modules using I²C

This is just a proof of principle and by far not the simplest solution for this job.

Using I²C allows for directly addressing up to 127 "slave" boards. Here the board on the right side in the video is the "master" (which initiates all transfers), the left board is the slave (waiting for data). I²C needs 2 signal lines and the usual power lines (+, -, SDA, SCL). As it is a bus, all devices are connected to it in parallel.