After a lot of thought and observation with my current design, I've decided to scrap it! Part of my decision comes from James Bruton with XRobots and his version 2 BB-8. I've decided it's a much better idea and has far more control than what many are doing already (omni-bot hamsters). You can read about and watch videos at James Bruton's website: http://xrobots.co.uk/BB8-2/. Now, I don't have James's design files and I can only determine his specifications based on what he's told us and by observation. Mine is going to differ quite a bit for various reasons. Number one, my 3D printer has a small build volume (145mm x 145mm x 155mm, Lulzbot Mini). I've already worked out most of the mechanics and I will be using existing electronics from the first version.
Another project has been in development for the remote control this BB-8 will use, so expect to see another project page spawn after a while! This universal remote utilizes a Raspberry Pi, TFT Touch Screen, and XBee Series 1. I'm still determining exactly what parts will be used for that project.
The dimensions are still 500mm (~20") in diameter and the drive wheel is going to be between 5mm and 6mm thick (thickest in the center). The drive wheel is going to be 260mm wide (from side to side). The main drive wheel is going to be 2 different panels that are being 3D printed. I don't want to 3D print this entire wheel, it would be 136 hours of printing! I'm going to 3D print a couple of these panels in HIPS (High Impact Styrene), clean them up, and hopefully made some molds to duplicate them. I'm hoping this will give better results (Harder, Better, Faster, Stronger). I need a total of 36 panels.
I'm writing this so early in the process that I'm just now starting to print the wheel panel prototype. This is also before I've even finalized the wheel's design. Technically this is just to see how well my printer can print this sort of shape. Initially I was printing a very early version of the panel on the bed with support material, but the support material proved to be too difficult to remove. In an updated version of the panel the outer ring is included (as it really should be) and it's printed standing up. This worked very well! The final result is the image farthest to the right.
MECHANICS & ELECTRONICS:
Driving the wheel will be 1 or 2 metal gear motors that have encoders, sound familiar? These are the same motors on my earlier prototype. The encoders might not be used, it's too early to tell. My earlier prototype used a 12V booster for the motors and speakers, but I may not do this on the new version because it might not be needed (testing might have to determine that). To give this droid the ability to turn a flywheel will be used very much like what's in James Bruton's build.
The brains will be an Arduino Due and a XBee Series 1 for wireless communication. I'm also bringing over the Adafruit Motor Shield v2.3, Adafruit 20W Class-D Amplifier, Robertsonics/SparkFun WAV Trigger, and at least one 4" speaker from the earlier project.
It's going to take a while to build the wheel after I've finalized it's design, but I'll be sure to post an update as soon as I start making the molds. Follow me on Facebook, Twitter, or Google+ to get updates.