reactionTimer.ino

const int LED_PIN = 13;
bool isOk = false;
bool lose = false;
int counter = 0;
int millis1 = 0;
int millis2 = 0;

void setup() {
  Serial.begin(9600);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  attachInterrupt(0, buttonPressed, RISING);
}

void loop() {
  if (!isOk && !lose) {
    int delayTime = (random(1,10))*1000;
    delay(delayTime);
    if (!lose) {
      digitalWrite(LED_PIN, HIGH);
      millis1 = millis();
      isOk = true;
    } 
  }
  else if (counter >= 5) {
    digitalWrite(LED_PIN, HIGH);
    delay(2000);
    digitalWrite(LED_PIN, LOW);
    lose = false;
  }
  else if (lose) {
    digitalWrite(LED_PIN, HIGH);
    delay(1000);
    digitalWrite(LED_PIN, LOW);
    delay(1000);
    counter++;
  }
}
void buttonPressed() {
 if (isOk) {
  Serial.println("WIN");
  digitalWrite(LED_PIN, LOW);
  millis2 = millis();
  Serial.print("Time: ");
  Serial.println(millis2-millis1);
  lose = false;
  counter = 0;
 }
 else {
  Serial.println("LOSE");
  lose = true;
 }
}