Geared Hexpod Neck
Because the sole purpose of a neck is to connect one's head to their body.
I recently replaced the large motor that I had been using to control the robot's head with a smaller servo. Although the servo has less torque it also carries many advantages. I still need to get a servo controller but once I do I will be able to get and set the position of the servo in degrees. I used two of the same gears so that I retain a 1:1 gear ratio so the degrees that the servo rotates will be the same as the degrees that the head rotates. The other advantages of the servo motor are that it is lighter weight, smaller in volume, consumes less power, and in general gives me greater control over the movement of the robot's neck.
The reason that I can get away with using the smaller servo is that all of the weight of the robot's head is supported by the universal joint at the center and the elastic supports on the sides. The elastic supports are just made from a strip of a used motorcycle inner tube. I choose the inner toob because the polymer material that it is made out of is denser and more durable than the polymer used to make rubber bands or surgical tubing. I still need some sort of linear actuators to control the position of the head in place of my elastic support system. Linear servos go for about $90.00 USD a piece and I would prefer to use something that was at most $15.00 just to keep the cost down. Ideally I would be able to create my own electromorphic polymer but I'm not really sure how to do that, yet.