led_dec_to_bin

const byte led1 = 2;
const byte led2 = 3;
const byte led3 = 4;
const byte led4 = 5;
const byte led5 = 6;
const byte led6 = 7;
const byte led7 = 8;
const byte led8 = 9;

int angka;//[10];

int ar_angka[10];
int i=0;

void setup() {
  // put your setup code here, to run once:
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(led7, OUTPUT);
  pinMode(led8, OUTPUT);

  Serial.begin(115200);
  angka = 255;
}

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

  for(i = 0; angka>0; i++){
    ar_angka[i] = angka%2;
    angka=angka/2;
  }

  Serial.print("jumlah i pertama: ");
  Serial.println(i);
  for(i = i-1; i>=0; i--){
    Serial.print(ar_angka[i]);
  }
  Serial.println();
  Serial.print("jumlah i kedua: ");
  Serial.println(i);

  digitalWrite(led1, ar_angka[0]);
  digitalWrite(led2, ar_angka[1]);
  digitalWrite(led3, ar_angka[2]);
  digitalWrite(led4, ar_angka[3]);

  digitalWrite(led5, ar_angka[4]);
  digitalWrite(led6, ar_angka[5]);
  digitalWrite(led7, ar_angka[6]);
  digitalWrite(led8, ar_angka[7]);
  delay(1000);
}