I have been able to setup my rainbowduino to receive the i2c command from my uno board. I am able to run the SeeedMaster sketch that sends the characters that are predefined in the data table.
Now I would like to send commands to the rainbowduino to set an individual LED and its intensity without modifying the original rainbowduino code.
Would I use the ShowChar function? Or is there something simpler I can send over the i2c link?
There isn’t a command in the standard firmware that can do that, you would need to add one. Building images a pixel at a time over I2C will be a bit slow too. What sort of images do you want to display?