Ultimo(?)-tentativo

const int ledpinEV1 = 22; // setta il pin elettrovalvola e led
const int ledpinEV2 = 23; //setta il pin elettrovalvola e led
const int ledpinEV3 = 24; //setta il pin elettrovalvola e led
const int ledpinEV4 = 25; //setta il pin elettrovalvola e led
const int ledpinPom = 26; //setta il pin elettrovalvola e led
const int ledpinRes = 27; //setta il pin elettrovalvola e led

const int puls = 4;  // setta il pulsante
const int Temp = A0; // setta il sensore temperatura
const int EV1 = A1;  // setta flussometro 1
const int EV2 = A2;  // setta flussometro 2
const int EV3 = A3;  // setta flussometro 3
const int EV4 = A4;  // setta flussometro 4

const int ingresso = 2;   //Piedino di ingresso del flussostato


double flusso;      //Quantità di acqua che scorre
volatile unsigned int count = 0; //Variabile di conteggio

char fromSerial = ' '; //Lettura dalla seriale

void impulso();
bool readSensors();

void setup() {
  Serial.begin(9600);

  pinMode(ledpinEV1, OUTPUT);
  pinMode(ledpinEV2, OUTPUT);
  pinMode(ledpinEV3, OUTPUT);
  pinMode(ledpinEV4, OUTPUT);
  pinMode(ledpinPom, OUTPUT);
  pinMode(ledpinRes, OUTPUT);

  pinMode(puls, INPUT);
  pinMode(Temp, INPUT);
  pinMode(EV1, INPUT);

  pinMode (ingresso, INPUT);  //Imposta piedino 2 in ingresso
  attachInterrupt (0, impulso, RISING);  //Configura interrupt 0 pin 2
}

void loop() {

  if (Serial.available())
    fromSerial = Serial.read();

  if (fromSerial != ' ') {
    switch (fromSerial) {
      case 'a':
        digitalWrite(ledpinEV1, HIGH);
        break;
      case 'h':
        digitalWrite(ledpinEV1, LOW);
        break;
      case 'b':
        digitalWrite(ledpinEV2, HIGH);
        break;
      case 'i':
        digitalWrite(ledpinEV2, LOW);
        break;
      case 'd':
        digitalWrite(ledpinEV3, HIGH);
        break;
      case 'l':
        digitalWrite(ledpinEV3, LOW);
        break;
      case 'e':
        digitalWrite(ledpinEV4, HIGH);
        break;
      case 'm':
        digitalWrite(ledpinEV4, LOW);
        break;
      case 'f':
        digitalWrite(ledpinRes, HIGH);
        break;
      case 'n':
        digitalWrite(ledpinRes, LOW);
        break;
      case 'g':
        digitalWrite(ledpinPom, HIGH);
        break;
      case 'o':
        digitalWrite(ledpinPom, LOW);
        break;
      case 'p':
        while (!readSensors()) { }
        break;
      case 'q':
        digitalWrite(ledpinEV4, LOW);
        break;
      default:
        fromSerial = ' ';
        break;
    }
  }
}

void impulso() {
  count++;   //Incrementa count di 1
}

bool readSensors() {
  int ELE1 = analogRead(EV1);
  delay(10); //Meglio lasciare questo piccolo delay per motivi interni ad Arduino
  int NTC = analogRead(Temp);

  count = 0;      //Resetta il conteggio
  interrupts();   //Abilita gli interrupt
  delay (1000);   //Pausa di 1 secondo
  noInterrupts(); //Disabilita gli interrupt

  flusso = (double(count) * 1.12);  //1.12mL per ogni impulso
  flusso *= 60.0;     //Trasforma i secondi in minuti
  flusso /= 1000.0;   //Trasforma i mL in litri

  Serial.print("HIGH\n");
  Serial.print("\tT: ");
  Serial.println(NTC);
  Serial.print("\tV: ");
  Serial.println(ELE1);
  Serial.print("\tF: ");
  Serial.println(flusso);

  digitalWrite(ledpinEV4, HIGH);
  delay(2000);
  digitalWrite(ledpinEV4, LOW);
  delay(2000);
  digitalWrite(ledpinEV4, HIGH);
  delay(2000);
  digitalWrite(ledpinEV4, LOW);

  if (NTC > 400)
    digitalWrite(ledpinRes, HIGH);

  if (flusso >= 2.0)
    return true;

  return false;
}