#include <Arduino.h>
const int sensorPin = 2;
volatile unsigned long count = 0;
unsigned long previousMillis = 0;
unsigned long interval = 1000;
void setup() {
  Serial.begin(9600);
  pinMode(sensorPin, INPUT);
  attachInterrupt(digitalPinToInterrupt(sensorPin), countRevolutions, RISING);
}
//----------------------------------------------------------------------
void countRevolutions() {
  count++; // Increment count on each interrupt
}
//----------------------------------------------------------------------
void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    float rpm = (count / 1.0) * (60000.0 / interval); // Assuming 1 pulses per revolution
    Serial.print("RPM: ");
    Serial.println(rpm,0);
    // Reset count
    count = 0;
    // Update previous time
    previousMillis = currentMillis;
  }
}