#define BUZZER A0
#define LED 7
#define PUSHBUTTON 4
#define TONE 0
#define LIGHT 1

enum Signal {
  Light,
  Tone
};

void setup() {

  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
  pinMode(PUSHBUTTON, INPUT);
  Serial.begin(9600);
}

void signalWrite( Signal signal, int lowhigh ) {
  if( lowhigh==HIGH ) {
    switch (signal) {
      case Tone:
        tone(BUZZER,250);
        break;
      case Light:
        digitalWrite(LED, HIGH);
        break;
    }
  } else {
    switch (signal) {
      case TONE:
        noTone(BUZZER);
        break;
      case LIGHT:
        digitalWrite(LED, LOW);
        break;
    }
  }
}
float measureReaction( Signal signal, uint16_t tests ) {
  float measurement_acc = 0;
  int   end_time   = 0;
  int   start_time = 0;
  bool  measurement = false;
  int   anzahl     = 0;
  while ( anzahl < tests ) {
    if ( measurement ) {
      if( digitalRead(PUSHBUTTON) == HIGH ) {
        signalWrite(signal, LOW);
        // zeit berechnen
        end_time = millis();
        measurement_acc += end_time - start_time;
        measurement = false;
        anzahl++;
      }
    } else {
      delay(1000+random(2000));
      if( digitalRead(PUSHBUTTON) == LOW ) {
        start_time = millis();
        signalWrite(signal,HIGH);
        measurement = true;
      }
    }
  }
  return measurement_acc/tests;
}

void loop() {
  float light_reaction = measureReaction(Light,2);
  float tone_reaction = measureReaction(Tone,2);
  Serial.println(light_reaction);
  Serial.println(tone_reaction);
}