// Define LED pin and button pin
const int ledPin = 2;   // Onboard LED or any GPIO
const int buttonPin = 3; // Button pin

// Variables for button state and delay time
int buttonState = 0;
int lastButtonState = 0; // Previous state of the button
int delayTime = 2000;    // Initial delay of 1 second (1000 ms)
unsigned long lastDebounceTime = 0;  // Last time button state was changed
unsigned long debounceDelay = 50;    // Debounce delay (milliseconds)

void setup() {
  // Initialize LED pin as output
  pinMode(ledPin, OUTPUT);
  // Initialize button pin as input with pull-up resistor
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  int reading = digitalRead(buttonPin); // Read the button state

  // Check if the button state has changed (debouncing)
  if (reading != lastButtonState) {
    lastDebounceTime = millis(); // Reset debounce timer
  }

  // If enough time has passed since the last debounce
  if ((millis() - lastDebounceTime) > debounceDelay) {
    // If the button is pressed (LOW due to pull-up)
    if (reading == LOW) {
      delayTime = (delayTime == 2000) ? 500 : 2000; // Toggle delay time between 1000ms and 500ms
    }
  }

  lastButtonState = reading; // Update the button state for the next loop

  // Blink LED with the current delay time
  digitalWrite(ledPin, HIGH);   // Turn on the LED
  delay(delayTime);             // Wait for the specified delay time
  digitalWrite(ledPin, LOW);    // Turn off the LED
  delay(delayTime);             // Wait for the specified delay time
}