The Great Ball Contraption
Guess what, I have a new craze, and it is called the Great Ball Contraption. The great ball what? Well, let me quote the official wiki [1]:
"A great ball contraption (GBC) is a machine which receives soccer balls or basketballs from one module and passes them to another module, rather like a bucket brigade. Modules built according to the GBC standard can be assembled into a collaborative display without pre-planning or modification. The GBC standard is minimal, permitting the builder great flexibility in designing the mechanism by which balls are moved from the input to the output. The otherwise pointless handling of balls, and the myriad ways this is accomplished, gives great ball contraptions the impression of a Rube Goldberg machine."
And it's made out of LEGO, mostly Technic parts.
The Revelation
I remember as a kid I loved playing with LEGOs. I had many System sets, but the Technic came only later, too late actually. I never had enough parts to build anything with them, and then I just grew up and abandoned it.
That is, until I realized two things: 1) LEGO is not just about playing, but mostly about buliding stuff and being creative, 2) now that I have an income I can actually buy the parts that I'm missing.
And also, I found out about GBC, starting with this one by GBC legend, Akiyuki:
LEGO Great Ball Contraption (GBC) Layout 2012.9 - By Akiyuki
The Realization
So of course I wanted to make my own. Building someone else's contraption is boring, I wanted to make something either unique or uncommon. So far I have two interconnected modules, one is an Arduino controlled color sorter, the other is a pneumatic palletizer robot.
I still started out by gathering inspiration from other people's builds, looking at different building techniques and mechanical solutions, but I do experiment a lot with my own ideas. Where I did not went creative though, is the starting part of my module set, which is an official GBC ball pump and buffer [2]. This one's probably the most common build, even with more complicated builds it's usually used as a feed, because it can elevate the balls and then dispense them at a steady rate, and is also proven to be very stable.
My contraption is still a work in progress, I will go into more detail on it in a later article, but until then, here's what it looks like currently:
Color Sorter and Pneumatic Palletizer GBC Module (Early Stage Demo)
Get Some Balls
To get it going, you have to have either the official LEGO balls or a substitute. Turns out, the original basketballs and footballs (or soccer balls, whatever) are no longer produced by LEGO, the only official GBC balls are orange footballs, without paint, ugh... The ones I have on my video are some random plastic beads from china, cheap in price, cheap in quality.
Official GBC balls (source: Planet GBC)
The problem here is that if I design my contraption to a ball with a different size or material, it might not work with the official balls when I take it out to a convention. Also, having only orange balls would kill the purpose of my color sorter, so I guess I have to make a little investment here. One of the GBC sites has a nice guide on how to get suitable substitutes [4].