good idea about capacitance Alec,
it really was as simple as some pvc pipe and foil, hooked directly to a digital I/O pin and ground, along with simple code:
while(1){
setpin1 output;
setpin1 on;
delay(1000);
setpin1 input;
counter = 0;
while (pin1=1){counter++;}
}
I tried 2 configurations:
1) OD wrapped foil anode and foil ball for cathode
2) two foil balls at each end of pipe
I found the first one to work better, plus with the OD foil wrapped over to the ID it causes immediate drop to 0v in the event of overflow, the only thing i notice as a problem is that the discharge time varies when my hand gets too close to either of the nodes, I worry that other outdoor environment factors may cause similar problems
any way i can compensate for this, maybe something like another foil layer tied to ground to act as Faraday cage?
also/or maybe it will be better if i move ground wire of pipe to another digital pin so i can truly flip polarities?