#define Center_switch 7  //assuming we use D2 on Arduino
static bool state;

int duration = 10;
int count=duration/2;

void setup() {
  Serial.begin(115200);
  pinMode(Center_switch, INPUT_PULLUP);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  if (debounce()) {
    digitalWrite(LED_BUILTIN, true);
  }
  else {
    digitalWrite(LED_BUILTIN, false);
  }
}

bool debounce() {

  if (digitalRead(Center_switch)) {
    count++;
  }
  else{
    count--;
  }
  if (count > duration) {
    state = true;
    count = 10;
  }
  if (count < 0) {
    state = false;
    count = 0;
  }
      Serial.print("count:");
      Serial.print(count);
      Serial.print(", debounce:");
      Serial.println(state);
      delay(5);
  return (state);

}