#define BUTTON_PIN 4

void setup() {
  Serial.begin(115200);
  //pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(BUTTON_PIN, INPUT);
}

int lastState = HIGH;
void loop() {
  int value = digitalRead((BUTTON_PIN));
  if (lastState != value) {
    lastState = value;
    if (value == HIGH) {
      Serial.println(" released");
    }
    if (value == LOW) {
      Serial.println(" pressed");
    }
  }
}