Instead of some sort of electrical device I made a pneumatic system to do the bubble lifter. This is fairly simple in concept, a small single acting spring retract air cylinder makes it work. When air pressure is sent to the cylinder the head goes up, when air pressure is removed the head returns to the low position. The only trick is to first know how much the parts that will move will weight and then calculate how big the air cylinder should be based on what air pressure will be used.

 

Together the bubble, brain, brain cup, light rods, crown, crown motor and assorted hardware weighs about 6 lbs. If the air pressure is around 20 psi an air cylinder of 1 1/8” diameter will be able to lift 14.7 lbs (this does allow for the 3 lbs force required to compress the return spring in the cylinder). This allows a reasonable factor of safety for any extra weight.