As clearly indicated in the circuit diagram two closely spaced metal rings are used as the water sensor mechanism.
Water flow sensor circuit diagram.
Arduino water flow sensor working.
I used a breadboard and once the connection was done as per the circuit diagram shown above my testing set uplooked something like this.
The water flow sensor circuit diagram is shown below to interface a water flow sensor and lcd 16x2 with arduino.
However one can use two metal needles injection needles to make the sensor.
Hence i have not used any external pull up resistors.
Internally the output pin of the hall effect sensor is pulled high on the circuit board itself as you can see in the breakdown image show above.
If the output valve of the pipe is closed the output of the water flow sensor is zero no pulses.
Flow diagrams are examples of concept diagrams used in many types of risk assessment to assist in identifying and understanding hazards particularly exposures to hazards hazard sources.
The pic below shows you the pinout of the water flow sensor.
If you are new to arduino and lcds you can consider reading this interfacing arduino and lcd article.
The sensor has a magnet and hall effect sensor.
If we take a look at the sides of the water flow sensor we can witness a plastic turbine in the path of water flow.
The circuit diagram for arduino water flow sensor interface is shown in the image below.
A round shaped magnet is embedded at the center of the turbine and the hall effect sensor is sealed and protected from moisture and placed above the magnet.
Water switch circuit schematic.