Great ball contraption
A great ball contraption (GBC) is a machine which receives soccer balls[1] or basketballs[2] 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 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.
Contents
Standard
This is a condensed version of the rules. The full, authoritative version of the standard is hosted at Team Hassenplug[TH].
The Balls
Soccer balls are typically used. Basketballs are also common. These were both available in various designs (search x45? and x493? on Peeron). Unfortunately, these were last sold in 2006. Some can still be found for sale on BrickLink (try searching for bb84* and x45*). However, in 2013 an orange soccer ball appeared in Heartlake City Pool.
Building Tips
Because GBC modules necessarily involve mechanisms, Technic elements and building techniques are frequently the basis of a GBC. However, creative use of non-Technic elements can substantially increase how well a GBC is received by both the public and AFOLs. Another key design factor is reliability, especially if the GBC will be part of a collaborative display. A GBC that works for 15 minutes before breaking down is fine at home, but at a 6-hour show it would break down 24 times–a significant hassle. Another common problem is “leakiness”, that is, having balls travel anywhere outside their intended path (usually onto the floor). Before taking a GBC MOC to a public show, run it non-stop for about an hour to get a good predictor of its reliability and leakiness. Some rules of thumb:
Collaboration
History
The idea was first publicly proposed by Steve Hassenplug on a LUGNET forum on October 7, 2004[SMART]. The GBC started as a “Ping Pong ball handoff” within the Lafayette LEGO Robotics Club, and was combined with SMART‘s Crate Contraption[Crate] to become The Great Ball Contraption. Other early participants included Bryan Bonahoom and Brian Davis.[TH] One of the early appearance of this collaboration was at Brickfest 2005.
Records
Formal records are not kept, and the only reward is boasting rights.
Examples
Some Great Ball Contraption Collaborations
Example Lift Mechanisms
A long list of possible methods to lift balls up from the in basket before passing them on (either to a widget or to the next in basket), can be found at Team Hassenplug[TH]. Some examples are given here.