Maximum Overhang?

[Synchron]

(sensor)
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/ (semitransparent mirror) - - - - (laser)
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_ (floating mirror)

[jsondag]

I think a capacitive sense would work best. Resistance is relative to salt concentration, and would require re-calibration every time. I could easily rig up a test with an arduino. you just need to tape a conductive strip to the outside of the container vertically, and submerge a corrosion resistant lead into the water. Gold coated PCB trace would be ideal, and cheap/easily salvageable. You can measure the capacitance which should increase linearly as the water level rises. You can measure it with an arduino using 3 pins, and two resisters, or using a 555 timer, to generate a digital modulated output which could be measured by your drip input on the peachy.

[CescoAiel]

Why not use the laser and a floating mirror on the resin. Messure the time, the laserlight needs to a sensor.

Hardest there would be to maintain the floating mirror's position!

I think a capacitive sense would work best. Resistance is relative to salt concentration, and would require re-calibration every time. I could easily rig up a test with an arduino. you just need to tape a conductive strip to the outside of the container vertically, and submerge a corrosion resistant lead into the water. Gold coated PCB trace would be ideal, and cheap/easily salvageable. You can measure the capacitance which should increase linearly as the water level rises. You can measure it with an arduino using 3 pins, and two resisters, or using a 555 timer, to generate a digital modulated output which could be measured by your drip input on the peachy.

Now there's a new and novel solution I hadn't thought of! Will it be accurate enough tho?

[jsondag]

Now there's a new and novel solution I hadn't thought of! Will it be accurate enough tho?

That's a good question. One that I think more relates to the parts used, and the resolution of said parts, than the method itself. I can test this maybe in the next day or two, just with some foil tape, and my multimeter, and see if that provides decent resolution. for a micro, the test involves charging the capacitor through a known resistance, measuring the time it takes, draining the cap, then repeating. The resistor value, and build of the "Capacitor" will need to be experimented with a bit.