# define FIRST_LED 3

String versionStr = "P04_A2 V1.0";

byte data = 0;
byte mask = 0;

int lv = 0;
bool led_state = false;
String nmbrstring;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println(versionStr);
  Serial.println("Bitte Zahl zwischen 0 und 255 eingeben");

  for (lv=0; lv<8; lv++) {
    pinMode(FIRST_LED + lv, OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  if (Serial.available()) {
    nmbrstring = Serial.readString();
    data = nmbrstring.toInt();
    Serial.println(data, BIN);
  }
  mask = 1;
  for (lv=0; lv<8; lv++) {
    led_state = data & mask;  
    digitalWrite(FIRST_LED + lv, led_state);
    mask <<= 1;
  }
}