volatile bool buttonPressed = false;
int btnCounter = 0;

void setup() {
  Serial.begin(9600);
  pinMode(2, INPUT_PULLUP); // Button on pin 2
  attachInterrupt(digitalPinToInterrupt(2), onButtonPress, FALLING);
}

void loop() {
  if (buttonPressed) {
    btnCounter++;
    Serial.print("Button was pressed! ");
    Serial.print("Counter: ");
    Serial.println(btnCounter);
    
    buttonPressed = false;
  }
}

void onButtonPress() {
  buttonPressed = true;
}