Practical question: This controller will operate out in the field, at night, where dew (possibly rain too) is a reality. I need to run a few wires (up to 12 or so, maybe less) between controller and the main instrument, and the connector must be sealed against humidity, obviously. The amperage through those wires is tiny, maybe 0.1 A each, peak.
The 20x4 LCD needs to be sealed around the edge, so that humidity doesn't get inside the box.
There will be a few buttons, maybe 6 or so, on the controller, to drive the menu displayed on LCD, those need to be sealed too.
Finally, there's a DC input connector that will need some kind of rubber cap.
I've not decided yet on the box that will contain the controller. Plastic and aluminum are obvious but not exclusive choices. The total size should be about half the size of a DVD-writer unit for a PC. I'm mentioning material and size only because this may influence the choice of connectors and buttons, otherwise this is not a problem.
Any ideas how to approach this issue in a way that's reliable?