There’s almost always more than one way to get any particular job done. Suppose for instance you have a tank you fill up from a well, and you’d like to know when the time is right to refill the tank. The obvious answer is to measure the level of the tank, and there are plenty of ways to do that. However, [Liam Hanninen] has a different approach. Using a flow meter, he measures how much water leaves the tank. Assuming that you know it was once full, you can deduce how much water is left.
Using a YF-S201 flowmeter on a Raspberry Pi, the code uses Python to populate a database. The meter will need to be calibrated to get an exact volume measurement.
There are many ways to measure flow. The YF-S201 uses hall effect sensors to measure the Yrotation of what amounts to a waterwheel. It counts the clicks of the wheel as the water turns it. However, there are many other possible types of flowmeters including those that measure the electric current generated by a slightly conductive fluid moving through a magnetic field. Other flow meters measure the cooling of a moving fluid across a hot wire.
Monitoring a tank level is a pretty common task. The tank doesn’t always hold water, though.
Source:: Hackaday