#define PPR 20  // Impulsi per rotazione del KY-040

unsigned long lastTime = 0;
volatile long pulseCount = 0;

void IRAM_ATTR countPulse() {
  pulseCount++;
}

void setup() {
  Serial.begin(115200);
  attachInterrupt(digitalPinToInterrupt(2), countPulse, RISING);
  lastTime = millis();
}

void loop() {
  unsigned long now = millis();
  unsigned long timeInterval = now - lastTime;
  
  if (timeInterval >= 1000) {
    noInterrupts();
    long currentPulseCount = pulseCount;
    pulseCount = 0;
    interrupts();
    
    float rpm = (currentPulseCount * 60000.0) / (timeInterval * PPR);
    
    Serial.print("Velocità: ");
    Serial.print(rpm);
    Serial.println(" RPM");
    
    lastTime = now;
  }
  
  delay(10);
}