Humanoid Robotic Torso PROTO1

UPDATED 12/30/2018 This is a project that I have been working on for 3 years now. I've published other prototype robotic arms and prosthetics I've designed mainly as a hobby including my "Humanoid Robotic Hand" which was just the arm of Proto1. The publishing of the complete set of files for the robot has been long overdue, but I've published the first prototype of the robot here and gotten much-needed feedback through an amazing community. I designed this robotic arm to be affordable, simple, and innovative. The total cost is around $300 and doesn't require an absurd amount of work to assemble. The arm features a 3-axis shoulder to obtain full human motion. The elbow uses a large servo connected to it by a grooved belt (the same kind of belt used on most FDM 3D printers), the belt allows the full 180 degree range of the servo to be channeled into the ≈100 degrees that the elbow moves. This is visualized much better in the video provided. The hand itself is composed of 6 servos. Betw