Our own BB-8 droid

Just found this:

It probably means other grey parts open and let other tools come out. I don't see how this can be done with a shell and a hamster movement system. It definitely requires a different propulsion system. Any suggestions?

As usual work and family matters slowed everything down. Moreover I lost my files in the most stupid way... and no backup.

Anyway I was going to make iteration 4 of the design (so not a huge loss), when I found these pics:

... and my doubts started to grow.

Are they spoilers? Should I try and add them to the project?

According to my measures the head diameter is just a bit smaller of an orange ring diameter, so it should fit. But now new questions:

Should the body open outside or inside in order to let the head enter? How to drive the head to the latch? Where to install the motor that opens the door? Are all 6 circles doors? and so on.

And what about the arms? are they external add-ons like in the toy? do they come outside from the grey parts in the circles?

I've been thinking about a "gyroscopic" body movement, but I couldn't find any literature about it. At least I couldn't find any holonomic mechanism driven by a gyroscopic mechanism.

In order to have opening doors and arms, the body should know its orientation. I think it will be a much easier task to achieve with a gyroscopic movement than with a hamster mechanism.

I would really like to start a discussion here, maybe in the comments, about if and how to add those features. Any idea is welcome!!

In the meanwhile I will see what I can do with the new Educational Boosterpack Mk II I just received from TI. I think about adding a couple esp8266 or cc110l RF Boosterpack to drive some motors wireless.

I finally received the 25x10 mm magnets from China. They are stronger than I thought.

The distance between the magnets is 20 mm. From the video below you can see that they hold quite strong.

In my design the body has a total shell thickness of 12 mm, maybe I can add a couple of mm to get extra stiffness and strength for the sphere.

BTW... the plastic parts are a prototype for the R2D2 rocket boosters, but that's another story... :)

I have been thinking about the spherical structure strength.

The original idea was to screw the orange rings to the grey triangles blocking the white circles between them. Moreover the orange rings were also designed to be screwed to the white circles.

Now that I have the parts printed I'm not so sure the orange rings will be strong enough.

I'll go back to the design board and modify the inner parts to provide the sphere structure and reduce the orange ring to simple covering without structural functions.

I modified the orange ring design adding abrim/cutout to the parts for a bigger glueing surface. The parts are only 4mm thinck and the joint wasn't strong enough.

Snapped together before glueing:

The ring parts look great and are very strong. I will also run them through a acetone vapour bath to make them stronger and of course glue them togeher.

After a major extruder failure, we are up again printing...

I tried different orientations. I wanted to print the parts in a vertical position to have more pieces printed together. Unfortunately the prints are quite weak.

Parts printed horizontally are much stronger.

Those measures and sketches were transformed in models using Fusion 360.

We designed the body parts so to be printed in different colours and screwed together. Several parts are ready to be printed.

We went through a few refinement cycles and made a few test prints.

The knurl nuts we are going to use:

Taking preliminary measures from the available images of BB-8.

Joining DIY forums discussing about the droid and how to build it.