float flowCalculation(unsigned long currentTime) {
  // Every second, calculate and print litres/hour
  if (currentTime >= (cloopTime + 1000))
  {
    cloopTime = currentTime; // Updates cloopTime
    if (flow_frequency != 0) {
      // Pulse frequency (Hz) = 7.5Q, Q is flow rate in L/min.
      l_minute = (flow_frequency / 7.5); // (Pulse frequency x 60 min) / 7.5Q = flowrate in L/hour
      // l_minute = l_minute / 60;
      flow_frequency = 0; // Reset Counter
    }
    else {
    }
  }
  return l_minute / 60;
  
}

void flow () // Interrupt function for arduino
{
  flow_frequency++;
}

// void IRAM_ATTR flow() // Interrupt function for esp32
//  {
//   flow_frequency++;
// }