const int buttonPin = 2;  
const int ledPin = 13;  
unsigned long previousMillis = 0;
int buttonState = 0;
int lastButtonState = 0;
bool isStopwatchRunning = false;
unsigned long stopwatchStartTime = 0;

void setup() {
  Serial.begin(9600);
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW); 
}
void loop() {
  buttonState = digitalRead(buttonPin);
  if (buttonState != lastButtonState) {
    if (buttonState == HIGH) {
      if (isStopwatchRunning) {
        isStopwatchRunning = false;
        unsigned long elapsedMillis = millis() - stopwatchStartTime;
        displayMillis(elapsedMillis);
      } else {
        isStopwatchRunning = true;
        stopwatchStartTime = millis();
        Serial.println("Stopwatch started.");
      }
    }
    delay(50);
  }
  lastButtonState = buttonState;
  if (isStopwatchRunning) {
    unsigned long currentMillis = millis();
    if (currentMillis - previousMillis >= 1000) {
      previousMillis = currentMillis;
      displayStopwatch(currentMillis - stopwatchStartTime);
    }
    if ((currentMillis - stopwatchStartTime) >= 60000) {
      digitalWrite(ledPin, HIGH);
      delay(1000);
      digitalWrite(ledPin, LOW); 
      // stopwatchStartTime = currentMillis; 
    }
  }
}
void displayStopwatch(unsigned long elapsedMillis) {
  int hours = elapsedMillis / 3600000;
  int minutes = (elapsedMillis / 60000) % 60;
  int seconds = (elapsedMillis / 1000) % 60;
  Serial.print("Stopwatch: ");
  Serial.print(hours);
  Serial.print(":");
  Serial.print(minutes);
  Serial.print(":");
  Serial.println(seconds);
}
void displayMillis(unsigned long elapsedMillis) {
  Serial.print("Elapsed Millis: ");
  Serial.println(elapsedMillis);
} //RIDHO MOHAMMAD AZRIL D400210120