The plastic eyes were purchased from eBay by searching for “doll eyes.”
Both eyes are mounted and held in place with a u-joint with fish swivels that hook onto the eyeballs’ edges to control them. One servo pitches the eyes up and down and a second servo pivots the eyes left and right. To control both eyes simultaneously, a free-spinning servo horn is embedded in the face plate with a bearing to freely spin.
For the eyelids, we 3D printed out a design from Thingiverse and added a ball connector to the side. Each eyelid has one servo with a connecting rod that closes and opens the eyelid. The eyelids were important because it adds realism with blinking, squinting, giving Sam a tired look, or conversely, a surprised look.
The eyebrows are simply servos with 3D printed brows that spin. Those are the simplest parts of the entire figure yet require the most maintenance in terms of redefining limits due to loosening.