void setup() {const int ledPin = 8;
const int buttonPin = 2;

bool ledOn = false;
unsigned long ledOnTime;
unsigned long reactionTime;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);
  Serial.begin(9600);

  randomSeed(analogRead(0)); // Better random
  Serial.println("Get ready...");
  delay(1000);
}

void loop() {
  // Wait for a random delay (1-5 seconds)
  unsigned long waitTime = random(1000, 5000);
  delay(waitTime);

  // Light up LED
  digitalWrite(ledPin, HIGH);
  ledOnTime = millis();
  ledOn = true;

  // Wait for button press
  while (ledOn) {
    if (digitalRead(buttonPin) == HIGH) {
      reactionTime = millis() - ledOnTime;
      digitalWrite(ledPin, LOW);
      ledOn = false;

      Serial.print("Your reaction time: ");
      Serial.print(reactionTime);
      Serial.println(" ms");

      delay(2000); // Pause before next round
      Serial.println("Get ready...");
    }
  }
}

  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}