Here is my Rainbowduino setup.
I am running NeoRainbowduino code version 3. It currently is not being updated (author switched to some new setup) but it works well enough. The communication flow diagram is below.
Since it is an 8×8 matrix with RGB colors, the rainbowduino needs data on 192 LEDs in order to function. The weird thing is, the Arduino code sends over 128 bytes of information. That’s 16 bits per 3 LEDs… which doesn’t add up. I have to spend a little more time digging around the code to figure out how to address the LEDs properly.
Also, the power supply system for the rainbowduino/arduino setup needs to be revised. The rainbowduino appears to absolutely need a DC-in power source to provide enough power for the LEDs. However, even with one connected, the microcontroller needs a 5v source – somehow the internal regulator only provides around 1 volt of power. This is confusing, maybe the voltage regulator on the rainbowduino is busted. Once again I’ll have to check it out later – for now the Arduino (red board) provides 5V power to the rainbowduino. (The Arduino gets 5V directly from USB.)
In the end I would like a standalone device that doesn’t require a computer or usb connection, so a single power system is absolutely necessary. A “good enough” solution may be to split the DC power in parallel and give some to the Arduino and the other to the Rainbowduino…. In theory just providing it to the Rainbowduino should work, but it doesn’t. The mystery must be solved….