#define LED_PIN 23
#define BTN_PIN 15

int btn_state;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BTN_PIN, INPUT);

  Serial.begin(9600);
}

void loop() {

  btn_state = digitalRead(BTN_PIN);
  
  Serial.print("ButtonState:");
  Serial.println(btn_state);

  delay(500);
}