Controlling three 4x4x4 cubes

Community Project Proposal
#1

Hello. I would like some advice.

I have a display idea that I want to build for a physics project. It involves not just one 4x4x4 RGB cube, but three 4x4x4 RGB cubes. I want to be able to control the colour/brightness of each LED in the cubes independently from a linux PC. I would write some software on the PC that could, for example, say “cube=2, row=1, column=4, layer=3 : red=0.5, green=0.2, blue=0.8” and that particular LED in the second cube would turn purple. I’ve seen examples of this being done for a single cube on YouTube, but could I do it for three?

Here are my specific questions?

  1. I think I can do this with the following:

    3 x Rainbow Cube kit- RGB 4X4X4 (#KIT101E1P)
    3 x Rainbowduino LED driver platform - Atmega 328 (#ARD127D2P)

That is, each cube needs its own Rainbowduino. Am I right?

  1. Can I control them with one USB cable (and then daisy-chain the Rainbowduinos)? Or do I need multiple cables?

  2. What do I need to buy to daisy-chain the Rainbowduinos together?

  3. Is the USB cable enough to power this, or do I need an extra power supply? The documentation talks about a 1A LDO, but I’m not sure what this is.

  4. Do I need a separate Arudino or something to interface the project to the Linux PC? Or can I control the Rainbowduinos directly?

  5. Is there are particular type of USB cable that I need to buy?

  6. Any thing else I need to buy for this project?

Sorry for so many questions. While I have no problems with programming, I’m completely new to Rainbowduinos, and I want to make sure I buy the right parts.

Much thanks in advance for any help you might be able to give me.

#2

Short answers to your questions:

  1. Yes, you’re right.
  2. One connection is enough, but the Rainbowduino (at least my version) has no USB connection so you need some kind of USB2Serial device (TTL not RS232). I think the new V3 has a USB connector but I don’t know enough about the new version to give you details.
  3. Nothing, as you can daisy chain them with the installed connectors (using I2C). To allow that they must be physically in a row, else have to make some cables between them.
  4. Three cubes have 576 LEDs (4x4x4 x 3 (RGB) x 3 (cubes)) of which 72 may be on at the same time. A LED consumes about 20mA => in total 1.4 A, way too much for a USB (500mA) and the power consumation of the rainbowduino is not yet counted. You definitely need an external power source of at least 2A.
  5. With a V2 you need something like a Arduino USB/Serial Light Adapter from the PC to your first Rainbowduino. With V3 you probably have that already on board.
  6. Yeah, one that matches :wink: In most cases this would be a USB A -> USB mini B cable.
  7. No, with the exception of the mentioned power supply.

Please keep in mind you cannot use the standard rainbowduino software, you have to adapt it for your special needs.

#3

Thank you very much for the reply. I really appreciate it. I think I have enough information now to get started… certainly enough to commit to purchasing some hardware. I realise that the software is going to be non-standard, but that is the area I am most confident that I can deal with.

Hopefully, I’ll be able to report soon and post up some notes and photographs on my (hopefully successful!) experiences.