most ez valami

float start, finished;
float elapsed, time;
float circMetric=2.093;
float circImperial;
float speedk, speedm;

void setup()
{
  circImperial=circMetric*.62137;

  attachInterrupt(digitalPinToInterrupt(2), speedCalc, RISING);
  start=millis();

  Serial.begin(115200);
}

void speedCalc()
{
  if((millis()-start)>100) // 100 millisec debounce
    {
    elapsed=millis()-start;

    start=millis();

    speedk=(3600*circMetric)/elapsed;

    speedm=(3600*circImperial)/elapsed;
    }
}

void loop()
{
  Serial.print(int(speedk));
  Serial.print(" km/h ");
  Serial.print(int(speedm));
  Serial.print(" MPH ");
  Serial.println();

  Serial.print("                ");
  Serial.print(int(elapsed));
  Serial.print(" ms/rev      ");
  Serial.println();
delay(100);
}