Different Matrix LED Configuration

Hi there, a bit of a newbie here looking for some help.

Bought a rainbowduino and an 8x8 LED matrix, but as it turns out the matrix pins aren’t in the same configuration as the rainbowduino headers. I read in the manual that this could be solved as its an open source platform, other than that one snippet of hope no other info or clues were given.
So I’m currently stuck at how to go about reconfiguring the pins :S

Any ideas? please

Thanks :slight_smile:

I can’t offer you much help here. If all you are trying to do is remap some colors you could probably mod the source to do that, but if the power and grounds are not on the same pins, it is not going to work without a lot of work, or at a minimum a new socket with the pins properly remapped. It is open source, and all the info is there, but this is not a trival change. If the leds are common cathode or anode makes a huge difference, and reworking the matrix would be huge if they are not the same. This design is nice in that you can control both the sourcing and sinking of current, but this involves driving the right power, while enabling the proper ground path to address each led within the matrix. The default matrix it was designed with has 3 leds in each of the 64 dots in a 8x8 grid which is 196 unique leds. As I remember the power is driven on 8 pins, and the current is sunk on the actual color pins. I once figured out the code for a mod, but it is tricky using half bytes to map each color of each pixel of each color in a very compressed space, and double buffering so the writing is done to an in memory copy that is not displayed until it is finished. Doing this on the original 168 was impressive. If you were asking for recommendations for hacking I would strongly recommend the updated board with the 328 on it for more flexibility. The large memory, program, and flash space is much easier on hacking.

If your led matrix doesn’t match the rainbowduino pinout then you are going to have to remap the pins from the matrix to the rainbowduino, or do it in software. Looking at the pin mappings on 2 different 8x8 RGB matrix units it’d would be no mean feat to do it in software so you could plug them directly into a rainbowduino, it would likely be quite impractical to do it in software too.

Heres a short rundown of how I remapped my 8x8 matrix to the rainbowduino.

The rainbowduino expects red and blue pins on one side in 2 blocks of 8 pins, on the other side it wants anode and green pins, 4 anodes, 8 green, 4 anodes.

If you posted the datasheet for your 8x8 matrix it would make things a lot easier. I’ll describe roughly how to translate the pin mappings from my datasheet and you can apply it to yours.

write out 2 columns, 1-16 in the first column and 17-32 in the 2nd. these will be the pins on the LED matrix.

1 17
2 18
3 19
. .
. .
16 32

The led matrix diagram will have 8 rows down the side(should be numbered 1-8), each having a pin number next to it.
it will also have 8 columns, each with a group of 3 pins (each number representing a colour, there will be a key as to which led diagram is which colour). We are going to translate the Row and columns to the anode/colour pins.

so, find Pin 1 in the matrix diagram and write down what it is in the list, here is the mapping on my matrix:
01 = column 1 Red LED 17 = Column 8 Blue LED
02 = Column 1 Green LED 18 = Column 8 Red LED
03 = Column 2 Blue LED 19 = Column 7 Green LED
04 = Column 3 Red LED 20 = Column 6 Blue LED
05 = Column 3 Green LED 21 = Column 6 Red LED
06 = Column 4 Blue LED 22 = Column 5 Green LED
07 = Row 8 Anode 23 = Row 4 Anode
08 = Row 7 Anode 24 = Row 3 Anode
09 = Row 6 Anode 25 = Row 2 Anode
10 = Row 5 Anode 26 = Row 1 Anode
11 = Column 5 Red LED 27 = Column 4 Green LED
12 = Column 5 Blue LED 28 = Column 4 Red LED
13 = Column 6 Green LED 29 = Column 3 Blue LED
14 = Column 7 Red LED 30 = Column 2 Green LED
15 = Column 7 Blue LED 31 = Column 2 Red LED
16 = Column 8 Green LED 32 = Column 1 Blue LED

once you have them all listed you can now start to map them out to the pins on the rainbowduino in groups of 8, here is the blue set of rainbowduino pins and the pins they should connect to on my matrix.

blue matrix
pin 1 pin 32
pin 2 pin 03
pin 3 pin 29
pin 4 pin 06
pin 5 pin 12
pin 6 pin 20
pin 7 pin 15
pin 8 pin 17

Repeat for Red, Green and Anode connections on the rainbowduino.

I hope that helps a bit :slight_smile:



On a similar note, is this product - http://www.seeedstudio.com/depot/60mm-square-88-led-matrix-bicolor-redgreen-p-35.html?cPath=163_165- meant to be rainbowduino compatible like the RGB matrix?