const int buttonPin = 8;
const int ledPin1 = 13;
int oldValue = LOW; 

void setup() 
{
  Serial.begin(115200);
  Serial.println("Tekan PB");
  pinMode(buttonPin, INPUT);
  pinMode(ledPin1, OUTPUT);
}

void loop() 
{
  int newValue = digitalRead(buttonPin);
  if(newValue != oldValue)
  {
    if(newValue == HIGH)
    {
      Serial.println("PB Ditekan");
      digitalWrite(ledPin1, HIGH);
    }
    else
    {
      Serial.println("PB Dilepas");
      digitalWrite(ledPin1, LOW);
    }
    oldValue = newValue;
  }
  delay(100);
}