Connect the VCC (Red) and GND (Black) wires of the water flow Sensor to the 5v and Gnd of Arduino, and link Pulse Output (Yellow) wire of the water flow sensor to Arduino’s digital pin 2. Note that ...

A sensor measures flow for the Arduino, which adjusts a control valve actuator to maintain the specified setpoint. The software uses proportional and integral control (the PI part of a PID loop).

To do that, I physically changed the conditions for each sensor to see how it affected the readings. For example, in bright light, my photoresistor had readings between 880 and 900, but when I ...