I work in home electronics, which often times we find ourselves needing to automate certain functions.
ie a theater projector screen to drop when a projector turns on.
12v to output from a processor when audio plays to trigger an amplifier on.
Point being, with all of these types of triggers as we call them. The simpler the better.
Seems like you need a trigger.
The event is When helmet is placed on the head, the electronics become active or deactive.
My thoughts are this.
The helmet needs to be completely autonomously operable and controllable on its own (for quick removale) Separate from the suit.
The act of placing the helmet will trigger the helmet eyes to deactivate.
My thought is to get a magnetic switch that is activated when the helmet is place on it.
This switch would turn on or off the power to the helmet? Depending on your desired outcome.
ie When helmet is placed on, magnet switch is tripped and cuts power to the eyes.
Maybe a magnetically activated relay? Normally open. When the helmet is placed on and magnet is detected it Closes the relay to complete the circuit?
I am not specifically aware of any magnetic switches that would work, but I am sure something exists.
This is a really great idea and great write up thanks for posting!