Stefan Mileschin

Finally the workings of the official BB-8 that you’ve seen rolling around at various events have been revealed. Its makers [Matt Denton] and [Josh Lee] participated in an hour-long presentation at Star Wars Celebration Europe 2016 just this past week where the various views of its internals were shown in action. It’s since had BB-8 builders (yours truly included) analyzing the workings for new ideas. We also now have the official name for it, red carpet BB-8.

For the first half of their talk they went over how BB-8 was implemented for Star Wars: The Force Awakens. As we’ve long known this was done using 7 puppeted BB-8’s, though it was revealed that only 4 were actually used, including a stationary one called the wiggler whose purpose you can guess. Another thing we didn’t know is that they did consider building a working BB-8 for filming but decided they needed something bullet proof, that would work right every time without making a film crew wait for repairs, and so went with the puppets instead.

The second half of their talk contained the big reveal, the mechanism inside red carpet BB-8’s ball. It turns out to be pretty close to what many builders have been doing. If you’ve seen the DIYer’s guide to the different BB-8 drive systems then you’ll understand when we say it’s a pendulum drive (aka axle drive). That is, there’s a motorized axle that crosses the middle of the ball and the ball rotates on that axle. Meanwhile a large mass suspended below the axle acts as the pendulum mass.

https://hackaday.com/2016/07/20/how-...ration-europe/