Using projective capacitive sensing with common keypads

[rcourtney]

I am looking at an attractive case for a protected outdoor keypad.  I don't want to use contact keypad sensing due to environment
deterioration of the carbon button spots.

Has anyone used capacitive sensing using these types of keypads?

Here, the dome and/or finger movement changes the field. 


I don't have the spec on the dome size or distance to the PCB yet.
Also, I may be using a PIC microprocessor.
Any advice is greatly appreciated.

Front view:


Internal enclosure parts: