Over the past few years I have designed and made hundreds of DMX Controlled gauges for TV and movies. A couple of hundred of my gauges were used in the B17 cockpits for Apple’s Masters of the Air series, and a hundred or so for the cessna cockpits used in Ridley Scot’s post-apocalyptic movie “The Dog Stars”. These were designed by me from scratch, to be controlled by DMX either from a control desk, or from DMX being output from TouchDesigner.
They use small stepper motors normally found in car dash-boards. These are small, low power and fantastically smooth and controllable.
However they have a limited range of movement, normally about 90 to 120 degrees at the most, whereas many airplane gauges need to be able to rotate a full 360 degrees in either direction, and sometimes make multiple revolutions. So every tiny motor had to be hand modified by me to allow for endless rotations.
Further, since the modification requires the removal of the end-stop inside the motor, it was now necessary to find a new way to know the position of the needle. So tiny microscopic holes had to be hand drilled in very precise locations on each motor. These holes were then used in combination with optical emitters and detectors to find the home position.
Sometimes we would stack multiple motors on top of each other for displays with “clock hands” but unlike a clock where there is a fixed ratio between the large and small hands, in an airplane gauge the hands need to be free to move independently. So more micro surgery was required to be able to know the position of every hand.
See my projects section for more details!