If you can drain a wire to ground, you can give it weak 5V and be able to read the pin to see how many reads it takes to fill the wire to HIGH. It will need calibrating and may be measurably subject to influence by external electrical fields.
If you can drain a wire to ground, you can give it weak 5V and be able to read the pin to see how many reads it takes to fill the wire to HIGH. It will need calibrating and may be measurably subject to influence by external electrical fields.