Código sensor de flujo (programa principal)

// reading liquid flow rate using Seeeduino and Water Flow Sensor from Seeedstudio.com
// Code adapted by Charles Gantt from PC Fan RPM code written by Crenn @thebestcasescenario.com
// http:/themakersworkbench.com http://thebestcasescenario.com http://seeedstudio.com
// Modificado por Jose David López A, Juan David López H, Alejandra Osorio O.

volatile int Contpulsos; //measuring the rising edges of the signal
float Q; // Caudal en lritos / seg 
int hallsensor = 2; //The pin location of the sensor
float v; //Volumen en litros
float Sv; //Sumatoria de volumen en litros
int t = 1*1000; //Tiempo 1 seg (delay=1000)

void rpm () //This is the function that the interupt calls 
{ 
 Contpulsos++; //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 () 
{
 Contpulsos = 0; //Set NbTops to 0 ready for calculations
 sei(); //Enables interrupts
 delay (t); //Wait 1 second
 cli(); //Disable interrupts
 Q = (Contpulsos / (7.5*60)); //(Pulse frequency ) / 7.5Q, = flow rate in L/segundo 

if (Q > 0)
  { 
   v = (Q*t)/1000; // se divide en 1000 para pasar el tiempo de milisegundos a segundos
   Sv = Sv+v;
   Serial.print (Sv, DEC); //Prints the number calculated above
   Serial.print (" litros\r\n"); //imprime volumen en litros (consumo de agua)
  }

else 
    {
   Sv = 0;
    }
}