Rainbowduino (LED Cube Matrix Question)

Products & Technology Arduino & Seeeduino
#1

Hello,

I just purchased a rainbowduino (I am assuming I am going to be sent v3.0, I purchased it off Amazon)

Regardless of whether or not it works for how I intended to use it, I am curious and would love some help trying to understand how I could drive individual LED’s off the board.

Specifically, I am interested in using it to drive NON-RGB LED’s for the moment, in a 5x5x5 matrix format (smaller if this is not possible), if this is possible how would I go about wiring it to the board?

Any sort of insight into the right approach would be super appreciated.

#2

I ordered the Rainbowduino from Amazon too, via MKC Electronics, and received v3.0b, which I believe to be the most recent version.

An RGB LED is really 3 LEDs in one package sharing a common anode or a common cathode. The Rainbowduino supports 64 RGB LEDs. If instead you want to support single-color LEDs, the board should support 3 x 64 = 192 of them. A 5x5x5 cube is 125 LEDs, so that is feasible. Another approach can be found for an 8x8x8 cube, and boards are available for that as well from someone in Holland, but that would not be supported by Rainbowduino directly.

The Rainbowcube kit schematic (http://seeedstudio.com/wiki/images/d/dc/Rainbow_Cube_Kit_-_RGB_4x4x4_LED_schematic_board.pdf) uses only a few parts beyond the LEDs and should give you hints for the hardware arrangement you need.

#3

Thanks for the information.

Was a bit confused at what the schematic was for, but I am assuming it’s for the chasis they built for the cube that you put the LED’s into, and then tie into the PCB?

I’m guessing it’s just a matter of tying the common anodes of my cube into the inputs of the 8 npn transistor array they have built into the board, and then putting each individual column’s cathode into the 8 different RGB inputs they have.

The only thing i’m curious about at this point is whether or not I am going to be able to pull off a 5x5x5 cube because of the 24 output pins (8 X RGB) and i’d technically need 25, plus 5 for the common anodes of the 5 rows in the cube.

#4

The Rainbow Cube schematic is for 64 RGB LEDs that are arranged on the really unusual thin PCBs that are both structural and wiring elements for the cube, as well as the “panel”, which is a base PCB that has about 5 resistors, a voltage regulator, the interface socket pins that plug into the Rainbowduino, and a few other parts, but no other chips. Aside from the LED arrangement, it is fairly simple.

Without having studied the schematic in much detail, I assume you will need to create simple electronics with resistors for current limiting that goes between the LEDs and the interface pins.

I’m sorry that I have not studied it enough to tell you more, but I do hope that you will share what you learn - I might well like to build one of these myself.

#5

Yeah, I will probably turn it into a little blog post or something documenting what and how I make up my cube, and interface it with the board since there seems to be a shortage of anything unless it relates directly to the premade or packaged cube itself.

I’m fairly certain though that I wouldn’t need any resistors on the LED’s as the drivers are constant current so there shouldn’t be an issue there relating to resistance, and the output going too high for the LED’s to handle.