int led = 13;
int saklar = 4;

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
  pinMode(saklar, INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int nilai = digitalRead(saklar);
  digitalWrite(led, nilai);
  Serial.println(nilai);
}