While I source some of the other materials such as an appropriate shell (I've found someone who is willing to make a resin cast of their own) and some other components I thought I'd begin experimenting with controlling an analogue gauge with an Arduino using the skills I gained making my K.U.D.
Using the measurements someone helpfully took of their own Radiacmeter and posted to the Ghostbusters Reference Library I've identified a suitably sized analogue voltmeter.
Alas, it looks nothing like the real screen.
However, the voltmeter I've ordered from Amazon can be taken apart and so I should be able to print off a new graphic to go in place of the old one. I've commissioned someone from Fiverr to turn the Minirad screen into a scalable vector graphic so I can resize and tweak it to fit. My running plan is that this can be glued inside the shell of the device so that it fits where the window is. As this will be recessed back in the shell I may need some additional acrylic to go on the surface but it kinda depends on how this resin shell turns out.
Sample image from Epic-Props (mine hasn't arrived yet so I don't know how much cleaning up will be needed)
Once again I'll be using an Arduino Nano to control the device. This is because I can use the analogWrite function to make the needle twitch. My current circuit consists of a 9V battery which is connected to a latching push button which I will put underneath the 'Test' button to effectively act as an on/off switch for the Arduino. The 'Read' button will be a momentary push button (i.e. it will only work when the button is held down) which will trigger the microcontroller to twitch the needle madly in the yellow/red areas. When idle (on but the 'read' button is up) then the needle will jiggle at the very low end of the green area to represent some sort of slight background radiation/spiritual presence. The real device has no sound but I might add a high pitch tone if there's enough room.
This is my Tinkercad project so far: https://www.tinkercad.com/things/crzVVH ... adiacmeter