#define BTN_PIN 15
int BTN_STATE;

void setup() {
 
  pinMode(BTN_PIN, INPUT);
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println("Hello, ESP32!");
  Serial.println("Let's Press Button");
}

void loop() {

  BTN_STATE = digitalRead(BTN_PIN);

  if (BTN_STATE == HIGH)
  {
    Serial.println("Button is pressed! ");
  }

  delay(100);
  
}