The first use of Audio-Animatronics was for Walt Disney's Enchanted Tiki Room in Disneyland, which opened in June, 1963. The Tiki birds were operated using digital controls; that is, something that is either on or off. Tones were recorded onto tape, which on playback would cause a metal reed to vibrate. The vibrating reed would close a circuit and thus operate a relay. The relay sent a pulse of energy (electricity) to the figure's mechanism which would cause a pneumatic valve to operate, which resulted in the action, like the opening of a bird's beak. Each action (e.g., opening of the mouth) had a neutral position, otherwise known as the "natural resting position" (e.g., in the case of the Tiki bird it would be for the mouth to be closed). When there was no pulse of energy forthcoming, the action would be in, or return to, the natural resting position. This digital/tone-reed system used pneumatic valves exclusively--that is, everything was operated by air pressure. Audio-Animatronics' movements that were operated with this system had two limitations. First, the movement had to be simple--on or off. (e.g., The open and shut beak of a Tiki bird or the blink of an eye, as compared to the many different positions of raising and lowering an arm.) Second, the movements couldn't require much force or power. (e.g., The energy needed to open a Tiki Bird's beak could easily be obtained by using air pressure, but in the case of lifting an arm, the pneumatic system didn't provide enough power to accomplish the lift.) Walt and WED knew that this this pneumatic system could not sufficiently handle the more complicated shows of the World's Fair. A new system was devised.
In addition to the digital programming of the Tiki show, the Fair shows required analog programming. This new "analog system" involved the use of voltage regulation. The tone would be on constantly throughout the show, and the voltage would be varied to create the movement of the figure. This "varied voltage" signal was sent to what was referred to as the "black box." The black boxes had the electronic equipment that would receive the signal and then activate the pneumatic and hydraulic valves that moved the performing figures. The use of hydraulics allowed for a substantial increase in power, which was needed for the more unwieldy and demanding movements. (Hydraulics were used exclusively with the analog system, and pneumatics were used only with the tone-reed/digital system.)
There were two basic ways of programming a figure. The first used two different methods of controlling the voltage regulation. One was a joystick-like device called a transducer, and the other device was a potentiometer (an instrument for measuring an unknown voltage or potential difference by comparison to a standard voltage--like the volume control knob on a radio or television receiver). If this method was used, when a figure was ready to be programmed, each individual action--one at a time-- would be refined, rehearsed, and then recorded. For instance, the programmer, through the use of the potentiometer or transducer, would repeatedly rehearse the gesture of lifting the arm, until it was ready for a "take." This would not include finger movement or any other movements, it was simply the lifting of an arm. The take would then be recorded by laying down audible sound impulses (tones) onto a piece of 35 mm magnetic film stock. The action could then instantly be played back to see if it would work, or if it had to be redone. (The machines used for recording and playback were the 35 mm magnetic units used primarily in the dubbing process for motion pictures. Many additional units that were capable of just playback were also required for this process. Because of their limited function these playback units were called "dummies.")
Eventually, there would be a number of actions for each figure, resulting in an equal number of reels of 35 mm magnetic film (e.g., ten actions would equal ten reels). All individual actions were then rerecorded onto a single reel--up to ten actions, each activated by a different tone, could be combined onto a single reel. For each action/reel, one dummy was required to play it back. Thus for ten actions, ten playback machines and one recording machine were required to combine the moves onto a new reel of 35 mm magnetic film.
"Sync marks" (synchronization points) were placed at the front end of each individual action reel and all of the dummies were interlocked. This way, during the rerecording, all of the actions would start at the proper time. As soon as it was finished, the new reel could be played back and the combined actions could be studied. Wathel, and often times Marc Davis (who did a lot of the programming and animation design for the Carousel show) would watch the figure go through the motions of the newly recorded multiple actions. If it was decided that the actions didn't work together, or something needed to be changed, the process was started over; either by rerecording the individual action, or by combining the multiple actions again. If the latter needed to be done, say the "arm lift action" came in too early, it would be accomplished by unlocking the dummy that had the "arm-lift reel" on it. The film would then be hand cranked, forward or back, a certain number of frames, which changed the start time of the arm lift in relation to the other actions. The dummies would be interlocked, and the actions, complete with new timing on the arm lift, would be recorded once again.
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