Hello, I need a sensor for detect the presence of water in a tank. I have no seen any sumergible water sensor for arduino. please, can anybody tell me wich sensor I can use
Two wires with stripped ends. No contact = no water. Contact = water. Just mount that near the bottom of the tank.
And electrolytically dissolved wires eventually. Nickel or stainless steel electrodes are one way to mitigate this, as is only powering up the sensor for short periods.
Common ways of tank sensing are:
pressure transducer mounted at bottom of tank - tells you how full, which is useful.
Capacitive sensors provide a no-contact method - many designs for this exist, worth a search, avoids the gradually corrosion problem.
Level sensing can also be done with ultrasonic detectors pointing down at the liquid surface