With some uncertainties regarding the sealing on the electronics enclose, i think it could be a smart thing to implement an water leak detector. I've checked the Cape schematics, and we have 2 ADC inputs we can use for this.
ADC4 and ADC5 on the Arduino mcu is not in use at the moment(as we dont use i2c atm.)
heres is a thread from the arduino forum that discuss a similar matter: http://arduino.cc/forum/index.php/topic,5961.0.html
Mechanicly i've thought of three posibilities for making the copper strip for the detector.
1. Use copper tape on each side at the very bottom of the vertical plate of the electronics structure.
Con: will not work when the structure is tilted..
the gap would then default be 3mm because of the acrylic thickness. the tape could also overlap slightly to give a smaller gap(higher sensitivity)
2: copper tape on each side of the right horizontal plate(opposite side of the servo).
Con: for best performance the notch at the bottom should be filled with a bit of acryl (maybe remove this notch in next revision?)
3. Two small vertical bits of tape on the "cable"endlid at the bottom of the tube.
Con: 1,cables connected to copper tape can conflict with moving electronics structure. 2. cables should be routed trough the 18-pin connector.
So.. any opinions? other thoughts?