Hi, my name is Tino and I live in Sabaudia - Italy (100km south of Rome on the coast). I am 64 and a beginner with arduino. My problem is to monitor the level of two wells that are designed to collect rainwater.
Wells are about 12 meters deep. and normally water level is 9 meters from the surface.
My first approach was for an ultrasonic sensor, the HC-SR04 for example, but I read that the maximum detectable distance is something around 3 meters. Another problem could be the water surface that should reflect the ultrasound and is not perfectly perpendicular to the direction of the emitter, so I might have wrong measures.
I also did some tests with a pair of infrared LEDs, one for transmission and one for reception but their setting is very complex, detectable distances are from centimeters to 2-3 meters and measures are really unreliable.
So I decided for a different solution. To dip a 9 meters object (eg. PVC pipe) that acts as a support to two very fine stainless steel wires that run parallel and opposite on the external surface of the pipe. In this way I could be able to detect the variation of the resistance when the water going up determines a short circuit at variable distances.
I read that using direct current even if of small intensity (eg. 5v or 3.3v) the phenomenon of electrolysis by depositing the material on the wires which act as electrodes could happen, altering the results. As a workaround I could reverse the polarity alternately.
Any suggestions ? Thanks.
this might be interesting to read
very interesting...
it is based on the variation of the dielectric constant determined by the water level in the capacitor and the pulsein measurement.
I will try and report.
thanks robtillaart
There are pressure sensors specifically built for measuring pressure in a liquid in wells but they are not cheap.
Search for "water level pressure sensor"
They are like this one
and you can find them also in Italy.
Some of them have also a little tube for compensating atmospheric pressure variations.