const int buttonIncreasePin = 2;
const int buttonDecreasePin = 3;
const int ledPin = 13;

volatile int delayTime = 500; // Initial delay time in milliseconds
volatile bool increaseButtonPressed = false;
volatile bool decreaseButtonPressed = false;
volatile unsigned long lastIncreaseTime = 0;
volatile unsigned long lastDecreaseTime = 0;

void setup() {
  pinMode(buttonIncreasePin, INPUT_PULLUP);
  pinMode(buttonDecreasePin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(buttonIncreasePin), increaseDelay, FALLING);
  attachInterrupt(digitalPinToInterrupt(buttonDecreasePin), decreaseDelay, FALLING);

  digitalWrite(ledPin, HIGH); // Turn off LED initially
}

void loop() {
  if (increaseButtonPressed) {
    increaseButtonPressed = false;
    increaseDelay();
  }

  if (decreaseButtonPressed) {
    decreaseButtonPressed = false;
    decreaseDelay();
  }

  digitalWrite(ledPin, HIGH);
  delay(delayTime);
  digitalWrite(ledPin, LOW);
  delay(delayTime);
}


void increaseDelay() {
  if (delayTime < 2000) { // Set an upper limit for delay
    delayTime += 500;
  }
}

void decreaseDelay() {
  if (delayTime > 100) { // Set a lower limit for delay
    delayTime -= 500;
  }
}