Learn about how Disney transformed Abraham Lincoln into a robotic figure Via ArsTechnica
Persistence of Vision states that a movement would be rehearsed, perfected, and then “recorded.” An engineer would use a potentiometer joystick that applied and measured the voltage differences going to a particular joint. Once he had the motion down, he would perform the gesture by generating the ups and downs of voltage with the potentiometer, and the transducer would translate that to tones recorded on film. The engineers would then play back the track to see that the movement worked correctly.
This sounds simple enough for a single movement, but most animatronic figures’ acts were composed of many different motions coordinated together. For instance, just raising an arm to point one’s finger to emphasize something they were saying would require shoulder, elbow, wrist, and finger movements that all had to happen in tandem. Movements for each joint for each act would be recorded on one reel, and then all the movement reels would be combined into a master tape. Persistence of Vision notes that for the Carousel of Progress exhibit put on by Disney at the 1964 World’s Fair, four narrator figures had a combined 120 actions that were all recorded on one one-inch 32-track master tape.
The other solution also used voltage regulation, but it didn’t require a system of timed cues. Instead of working on one joint at a time with a transducer and potentiometer, engineers used a wearable control harness, visible in the Dave Smith video, that was hooked up to an animatronic figure. The harness measured voltage differences across its various joints and mimicked the changes in the animatronic figure connected to it, recording the movements to tape. The harness had the benefit of being able to record complex multi-joint movements, but it required perfect performances from the wearer, who had to sit for hours trying to get the motions right.