// set pin numbers
const int buttonPin = 4;  // the number of the pushbutton pin
const int ledPin =  5;    // the number of the LED pin

// variable for storing the pushbutton status 
int NewbuttonState = 0;
int OldbuttonState = 0;

void setup() {
  // initialize the pushbutton pin as an input
  pinMode(buttonPin, INPUT);
  // initialize the LED pin as an output
  pinMode(ledPin, OUTPUT);
  // inisalisasi serial
  Serial.begin(115200); // 9600, 1200
}

void loop() {
  // read the state of the pushbutton value
  NewbuttonState = digitalRead(buttonPin);
  // check if the pushbutton is pressed.
  // if it is, the buttonState is HIGH
  if (NewbuttonState != OldbuttonState) {
    if (NewbuttonState == HIGH) {
      // turn LED on
      Serial.println("the button is PUSHED");
      digitalWrite(ledPin, HIGH);
    } else {
      // turn LED off
      Serial.println("the button is RELEASED");
      digitalWrite(ledPin, LOW);
    }
    OldbuttonState = NewbuttonState;
  }
}