How to Build Your Own Animated BB-8
Using 2 polycarbonate spheres (Head: 300mm and Body: 500mm) made quick work of body fabrication. You can also choose to use paper mache over a ball or 3D print your body, but you can't beat the spheres for speed and simplification.
The head needs to be 170mm tall and a simple holder for a pen at that height helps draw a cut line. Simply spin the sphere on a flat surface against the pen for the line.
Cut the sphere along the line carefully with a rotary tool. The slower and more precise at this stage will minimize any sanding and filling later.
Using pink foam from the hardware store, the beveled bottom of the head can be trimmed to size. Use two layers, one to fit snug in the head and another to be beveled.
Coat the entire surface of the foam in 2-part epoxy to seal the foam for painting.
We're now starting to take the shape of BB-8! The body and head have been spray painted satin white in order to match. If you look closely at the movie stills, BB-8 is actually more of an ivory color than true white. However, in the weathering process it's easier to achieve that shade than matching it in spray paint cans.
To make the eye, you can 3D print the parts or simply build one from craft foam. Check your dimensions and cut strips and glue them with epoxy.
Use a holiday craft ornament for the clear plastic for the eye.
The remainder of the eye details are fabricated from foam, cardboard and wire.
Since craft foam does not accept paint well, coat the entire eye assembly in epoxy. Once dry, spray paint mat black.
I considered drawing and masking off templates to pain the colored graphics, however, it proved much faster to draw effects on the computer using Photoshop and then printing them on 8.5"x11" vinyl sheets.
While measuring each orange circle pattern (6 in total), a compass can help lightly score an outline circle to help align the stickers. Simply trim the graphics out of the sheet and carefully apply them.
Chartpak tape (1/32 or 1/64 thickness) helps make clean straight lines around the body and head. This tape can also work well to make smooth curves as well.
The chrome strip line around the head is started with black electrical tape.
A strip of aluminum tape (trimmed shorter than the black electrical tape) is then wrapped around on top.
The top of the head is measured out and a compass is used to score two circles where the aluminum panels reside.
Aluminum Foil tape wedges are cut out out and over lap the top and bottom lines.
Sharpening the end of the compass can score and cut right through the tape so that the scrap ends can be peeled off and discarded.
The space between is then trimmed with a black marker.
The remainder of the head stickers are applied. Holes for lights are cut out and in the case of this blue light, a piece of plastic is glued in the slot.
The head and body are finally decorated.
We took our BB-8 down to our local Maker club to check out the progress on other projects. Even at this stage, the prop received a ton of praise and interest.
The lighting effort began by using small LEDs being instered into small tatoo mixing cups. A holder fashioned from foam-core board was hot-glued together.
In some cases, gluing multiple mixing cups together resulted in a more diffused color spread.
Aluminum foil tape was used to seal the wires and block any light bleed coming from cups. Lining the foam core holders with aluminum tape helps the light bounce around and make more of a soft glowing effect.
The lights were all secured inside the sphere with hot glue.
In order for the light to shine through, the stickers needed to be cut and the white spray paint scratched off with a hobby blade.
BB-8 will be set up on a motion sensor and will light up, make noise, and turn his head while people walk by. Here's my simplified motion sensor build using a motion sensor, junction box (to house the connections) power strip, and extension cord.
By inserting the motion sensor in the power strip cord, everything (including speakers, LEDs, and head motor) will activate upon the motion sensor. Begin by cutting the cord on the power strip and separating the wires.
The motion sensor gets screwed into the junction box. Make sure the motion sensor has a "test" function so that it comes on and off within a few seconds (versus 5 or 10 minutes).
There are many wiring diagrams online for this and the junction box will house the wires. Check the effect by plugging a lamp into the powerstrip and ensuring the motion sensor can activate it.
The final assembly is clean and can be hidden from view.
Here is the full assembly including some basic speakers. The speakers will fit inside the body and an MP3 player has all of BB-8's talking and chirping sounds plugged in as well.
To turn the head, a small electric motor (110V AC 5-6RPM Generic TYC-50 Synchronous Motor CW/CCW Torque 4Kg.cm) was set up on top of the body.
The 3D printer arrived just in time and using Photoshop, you can create 3D parts. I tested and operated these in Photoshop before printing them in order to get a back and forth head turn.
The entire assembly was screwed together and bolted on top of the body. A brass rod was cut to size and a flat plate screwed on to velcro to BB-8's head.
The fuzzy muff on top of the brass rod is sticky back velcro that the head sits on top of.
Assembled and plugged in.
Additional parts (antennas and holoprojector) were created on the 3D printer.
The weathering process is what takes this project from a toy to a realistic prop. Using acrylic craft/model paints, the key here is to apply very light washes across the surface. Make sure to add a drop of dish soap (not hand soap) to the wash to break the surface tension and to also make it a "wipe-able" effect.
Starting with a light sand yellow color, a large brush applies the color in a stippling effect.
Next, gently take paper towels wadded up and blot the surface. Changing out the paper towel regularly helps ensure a consistent mottled surface across. This is how BB-8 begins to take on the ivory color.
Create a darker shade of grey/brown and stipple this around the orange markings.
Blot this color as before. You might need to add a 3rd and 4th shade to create the desired effect.
Getting close to finishing the weathering process.
Weathering to the head is completed in a similar manner and details are painted and applied.
Spraying a few coats of clear will help seal and protect the work to this point.