In the case of sensing water level, the issue of an DC signal, using 2 SS metal probes in water (one source, one sink) causing electrolysis is well known. From my own experimentation, an AC signal being passed between two probes does no have the same issue of electrolysis (which makes sense).
What about reading water level using two analog I/O pins from a micro-controller and just alternating +V and Read instead? Would this not be an alternating current system as well?
Just throwing this against the wall for anyone to comment on.
I can confirm that it does work for measuring soil moisture, i tried this for my soil moisture sensors:
https://gardenbot.org/howTo/soilMoisture/
Around halfway down the site
Not sure abut measuring water level, but test it and see.
I really appreciate you documenting this flip flop circuit. Your circuit is the same as I imagined it to be, but your code is slightly different (though more direct) so I appreciate that too. I doesn't look like you are smoothing the code at all here. Did that still work well for you?
Given the application was a soil moisture sensor, could you verify it to be a stable reading in a situation where the water levels are rapidly changing? I would be trying this in a system where I am rapidly dispensing water.
Do you have any pictures of the two probes post testing?
I will try this flip/flop circuit regardless. Thanks again.
Not my page I'm afraid I only copied the idea for my own sensors, i use it in a wireless sensor and take 2 readings every 4sec and I get a nice even curve, high temperature variations can make a small jump here and there thou.
I'm interested to see what results you get, might use it for something if it works.
I made note of your user name. I will update you in the case that I try this. Turns out that I 'stumbled' on a capacitance system that may work even better (and not touching the water at all) which of course would be ideal.
Still, it's good you directed me to this information. 