const int buttonPin = D2;  // pushbutton pin
const int ledPin = D3;     // LED pin

int buttonState = HIGH;    // matches the resting (unpressed) state with INPUT_PULLUP

void setup() {
  Serial.begin(115200);

  // enable internal pull-up resistor
  pinMode(buttonPin, INPUT_PULLUP);

  // LED output
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // read the state of the pushbutton (LOW = pressed, HIGH = not pressed)
  buttonState = digitalRead(buttonPin);
  Serial.println(buttonState);

  // button pressed?
  if (buttonState == HIGH) {   // not pressed
    digitalWrite(ledPin, HIGH);  // turn LED on
  } else {                      // pressed
    digitalWrite(ledPin, LOW);   // turn LED off
  }
  delay(1000);
}