When the first teaser trailer for Star Wars: The Force Awakens dropped, the few frames that caught everyone’s eye — aside from a ridiculously contentious lightsaber design — was the delightful new BB-8 droid, rolling and bouncing as gleefully as a robot could. Even more eye-catching was the moment that the actual BB-8 rolled on stage at 2015’s Star Wars Celebration in Anaheim, California. No CGI, no force, no faking.
So if the little ball droid is all practical effects (to the joy of fans), how does it work?
BB-8 is similar to a toy that’s been around for years: Sphero, a remote-controlled ball that moves about with interior wheels and gyroscopes. In fact, the filmmakers reportedly worked with Sphero on the mechanics of BB-8, and Sphero’s website looks to be teasing its toy version of the droid. Furthermore, a patent submitted by Sphero looks surprisingly similar to BB-8, and the current version of Sphero’s main toy is similar enough to BB-8 that you can make a low-grade version of your own with only slight modifications.
OK then, BB-8 looks to basically be a sophisticated and super-sized Sphero, but what does that mean? Well, until Lucasfilm reveals the technical specs (if ever) we won’t know for sure. However, assuming that it’s pretty much a Sphero gives us a good idea where to start.
As many have pointed out, the webcomic xkcd may have already solved this one by accident when imagining a hamster ball for a PC. With omni-directional wheels, a gyroscope, batteries, and an adjustable internal arm with magnetic rollers, xkcd‘s hamster ball could roll around just like BB-8 and have a head held in place by the magnets.
With this basic design, BB-8 could roll around in any direction while independently turning its head. In short, the secret to BB-8 surprising movement is likely magnets and some clever engineering, no force required.
May the 4th be with you!