Best Arduino Flow rate Sensor Tutorial for Beginner

Parts list

- Arduino Uno
- Water Flow sensor
- Resistor 10K ohm
- Jumper wires

schematic diagram

Arduino Sketch Code

// reading liquid flow rate using Seeeduino and Water Flow Sensor from
// Code adapted by Charles Gantt from PC Fan RPM code written by Crenn
// http:/

volatile int NbTopsFan; //measuring the rising edges of the signal
int Calc;                               
int hallsensor = 2;    //The pin location of the sensor

void rpm ()     //This is the function that the interupt calls 
 NbTopsFan++;  //This function measures the rising and falling edge of the hall effect sensors signal

// The setup() method runs once, when the sketch starts
void setup() //
 pinMode(hallsensor, INPUT); //initializes digital pin 2 as an input
 Serial.begin(9600); //This is the setup function where the serial port is initialised,

 attachInterrupt(0, rpm, RISING); //and the interrupt is attached
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop ()    
 NbTopsFan = 0;      //Set NbTops to 0 ready for calculations
 sei();            //Enables interrupts
 delay (1000);      //Wait 1 second
 cli();            //Disable interrupts
 Calc = (NbTopsFan * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour 

 Serial.print (Calc, DEC); //Prints the number calculated above
 Serial.print (" L/hour\r\n"); //Prints "L/hour" and returns a  new line