I'm always on the lookout for fun and engaging electronics projects for kids. A few days ago I dropped by RadioShack (I needed an IR sensor for an Arduino project) and noticed a red box labeled RadioShack 3D LED Cube Hobby Kit. As it was priced at under $15 I had to give it a try.
If you are not familiar with LED cubes, do a quick YouTube search.
For anything impressive you want a large cube, the bigger the better, and you also want RGB LEDs. But large LED cubes can be very tricky to put together, and coding them is not trivial either. And when you add RGB into the mix you're doubling the number of connections you'll need to solder. So, small cubes of single-color LEDs is a good place to start. The RadioShack kit is a simple 3x3x3 cube, 27 LEDs in total, all powered by a single Arduino board (not included). You get (almost) everything you need in the kit, along with some pretty decent directions. This accompanying blog post has product details, and downloadable Arduino code complete with a bunch of lighting patterns that are ready to run.
I worked on this with one of my sons this week. This was not a trivial project. 27 LEDs, 9 resistors, and 4 sets of header pins, well, that is a lot of soldering on a small board and a cube that is not much bigger than an inch in each direction. And yes, there were mishaps (I managed to burn out a couple of LEDs after the cube was soldered together), but that's part of the fun. And now that we're admiring the results, it's clear that this was well worth the time and effort.
I'd not recommend this project if you have no experience with a soldering iron. But that said, this is a great, inexpensive way to have fun with electronics and simple programming.