Water flow sensor can be used to measure the flow of liquids, i.e. the consumption of liquids in industrial or domestic usage. For example you can make a robotic cocktail dispensing machine, and can use this sensors to accurately measure components like Soda, Water, etc. Water flow sensor consists of a plastic valve body, a water rotor, and a hall-effect sensor. When water flows through the rotor, rotor rolls. Its speed changes with different rate of flow. The hall-effect sensor outputs the corresponding pulse Signal.