My latest interest has been in building three dimensional LED cubes shown in the videos below. Why the interest in digital electronics in addition to building websites? The world is saturated with mobile apps and websites, each promising to improve some aspect of our lives and our social experience. There is something limiting, though, about this experience being delivered merely in a 2D world of phones, tablets, and flat screens. Let's expand to a world of expression in 3D! Whether through virtual media like these LED cubes, or physical media like 3D printers and robots, doing so will greatly enrich our lives!
The cube shown here is made up of 4,096 RGB LEDs driven by nine Arduino Mega 2560s. It is composed of eight pairs of LED panels, each panel containing 256 LEDs for a total of 512 LEDs per pair. Each panel pair is driven by one Arduino Mega programmed as an I2C slave. The eight slaves are, in turn, controlled by one Arduino Mega master that keeps the slaves in sync, much like a conductor in an orchestra.
This is my first 8x8x8 cube built by soldering together 512 3mm bright blue LEDs. There are kits out there that provide all the parts you need along with the programming, but I chose to build this from scratch and to program the cube from the ground up. One might argue that I re-invented the wheel by doing so, but this gave me an opportunity to experiment with different circuits and multiplexing layouts. In this case, I am handling the multiplexing through an array of eight eight bit serial-in parallel-out shift registers, along with a three-to-eight decoder to control the cathode layers. The brains driving it all is an Arduino Mega 2560.
The prototype I built here before the 8x8x8 uses a 4-to-16 decoder to handle the multiplexing, simple and adequate for a 4x4x4. I would always recommend that you start with one of these before moving to an 8x8x8. It'll give you a chance to sharpen your soldering skills on a less "risky" project.