BB-8 Droid from Star Wars (v2) - Homemade/DIY

This is a work-in-progress of version 2 of my BB-8 droid. The motor in version 1 wasn't strong enough to enable the use of a full featured dome that would stay on (the head is commonly called the dome).

So for version 2 I decided to:

  • use powerful drill motors and drill batteries from cordless drills,
  • switch to a tank/differential drive so that it can turn better,
  • add sounds,
  • eventually add inertial management for more stability.

In the animated GIF below you can see it's working well as of November 9, 2016, though there's still some stability improvement to be made.

Homemade/DIY BB-8 (v2).
Homemade/DIY BB-8 (v2).

Below are photos of the drive system, or what's commonly called the hamster since it acts like a hamster running inside a ball, making the ball roll. Magnets at the very top are what keep the head on from magnetic attraction through the ball.

The drive system/hamster.
The BB-8's drive system/hamster.
The BB-8's drive system/hamster.
Sitting in the bottom hemisphere of the BB-8 droid.

Below are some views of how the head is held onto the ball. You can see the magnets (taken from old hard drives) that are attracted to the ones mentioned above as a part of the drive system in the ball. You can also see the rollers, made with brass tubes and marbles, that keep the contact with the top of the ball fairly frictionless.

BB-8's head on the ball.
BB-8's head on the ball showing how it's held on.
Looking under BB-8's head.
The magnets and rollers visible under BB-8's head.

Making BB-8 (v2)

3D model for BB-8 (v2)

To help design and fit this BB-8 droid together I have a 3D model drawn up in Blender 2.71, a free 3D modelling and animation software. The model changes as my BB-8 changes. The latest version of it can be downloaded here:

bb8_design_v2_20160530.blend - 2.64MB, made using Blender 2.71 and the Blender Renderer (i.e. not Cycles)

3D model for BB-8 in Blender
3D model for BB-8 in Blender

Detailed BB-8 making pages

See the following webpages for much more detail about the making of this BB-8 (v2). Videos showing the making of it step-by-step are also below. You can find a BB-8 (v2) partial parts list here, including only the items I had to buy.

BB-8 (v2) drive system.

The first thing I made was BB-8's drive system/hamster, consisting of drill motors, drill batteries, some 3D printed gears, some bearings and two rollerblade wheels.

BB-8 (v2) drive system electronics.

That was then followed by BB-8's drive electronics, consisting a circuit I dreamed up for converting the output of a toy truck's radio control receiver to something an Arduino can understand and a made-from-scratch dual H bridge board for controlling directions the motors turn.

Attaching BB-8 (v2)'s head.

BB-8's ball and head need some way for magnets to hold the head on and so I made support structures for inside the ball and under the head, keeping them both lightweight since any weight near the top of BB-8 will make it wobble more. This is also the point where I added rollers to the bottom of the head so it can roller over the ball as the ball moves under it.

Fiberglassing BB-8 (v2)'s ball.

Here's how I added three layers of fiberglass to BB-8's cardboard globe to make it more rigid. The weight of the drive system would deform the ball, and even though it worked, it was very hard to tape the two hemisphere's closed, requiring a lot of tape around the equator. The uneven surface made by the tape would interfere with the movement of the head over it. There was also some flatness at the poles which I was able to fix at the same time.

Adding IMU/gyro for stabilization.

I added the BNO055 inertial measurement unit (IMU) board from Adafruit to get some stabilization, eliminating some wobble.

Detailing, adding LEDs and painting.

I made BB-8 look like BB-8 by adding details to the head such as the radar eye, holo projector and the antennas. Then I added some LEDs to the head. And lastly I painted the head and the ball.

Video - Making BB-8 (v2) Droid - Part 1

The following video is part 1 in a series on making this BB-8 droid and shows it rolling around and turning followed by showing the making of it step-by-step. This is all the steps needed to get it to the point of moving around, including turning.

Video - Making BB-8 (v2) - How to Fiberglass - Part 2

In this video I show step-by-step fiberglassing the cardboard globe.

Video - Making BB-8 (v2) - Reattaching the Head - Part 3

I purchased new magnets and in this video I show how used them with a new head support and internal support to get the head working with the new fiberglassed ball that I made in part 2. As you can see in the video, it works great!

Video - Making BB-8 (v2) - Adding Gyro/BNO055 IMU - Part 4

The first working version wobbled quite a bit back and forth when stopping so I added a gyro, the BNO055 Intertial Measurement Unit (IMU) from Adafruit to detect that wobble and run the motors to counter it. This video shows adding it, as well as the work done so far in software to stabilize it.
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