When CalArts was putting on Oedipus the King, a partner and I were assigned to develop a set of automated platforms that would pop out from the stage, creating an X; I tackled designing the 20'x4' long cantilevered platforms as well as the design/implementation of the control and safety systems.
For the platforms I decided on using a box truss we had on hand as a "spine," as fabricating a structure capable of such an extreme cantilever would be both cost-prohibitive and time consuming. With CNC cut plywood "ribs" that, when installed, locked into the truss, I was able to create structure that only added 1" to the truss's overall thickness. These choices resulted in a sturdy deck that actors could safely traverse despite lacking any conventional framing.
For the automation, the shorter end of each teeter totter was pulled below the deck by way of chain motors. When in its lowered position the long end had a support to rest on. However, if unaddressed, if to many actors were on the short end it would tilt causing the floor to fall out beneath there feet (not ideal). I addressed this by placing an electromagnetic lock on the long end of the teeter totter which brought the weight capacity of the short end up to about 2000 LBS. As a redundancy I also placed limit switches past the intended travel of the teeter totters so that if the chain motor limit switches were to malfunction the operator would be immediately notified. Luckily they were never triggered in the teeter totters' Operation.
Bellow you can find the platform's draftings as well as operations manual.