#define LED_PIN 8
#define BUTTON_PIN 7

byte lastButtonState;
byte ledState= LOW;

unsigned long lastTimeButtonStateChanged = millis();
unsigned long debounceDuration = 50; // millis

void setup() {
  pinMode(LED_PIN, OUTPUT); 
  pinMode(BUTTON_PIN, INPUT);
  lastButtonState = digitalRead(BUTTON_PIN);
}

void loop() {
  if (millis() - lastTimeButtonStateChanged >=  debounceDuration) {
    byte buttonState = digitalRead(BUTTON_PIN);
    if (buttonState != lastButtonState) {
      lastTimeButtonStateChanged = millis();
      lastButtonState=buttonState;
      if (buttonState == LOW) {
        if (ledState == HIGH) {
          ledState= LOW;
        }
        else {
          ledState= HIGH;
        }
        digitalWrite(LED_PIN, ledState);
      }
    }
  }
}