Hello
I want to use ultrasonic sensor(like HC-SR04) for measuring depth of oil in 3500l tank. Tank is almost 2m high(190cm) so the sensor would be at its limit.
The distance between sensor mounted on top of tank and oil level Arduino would calculate how much oil is left in tank (full tank height - measured distance = oil left in cm) Then i woud like to convert this distance of oil to liters, but since the tan is custom made and at an angle this could be only calibrated during filling of the tank.
Another way is to use diferential pressure sensor.