#define btn 5
void setup() {
  // put your setup code here, to run once:
  pinMode(btn, INPUT);
  Serial.begin(9600);
  digitalWrite(5, HIGH);
}

int data;
void loop() {
  // put your main code here, to run repeatedly:\
  int data = digitalRead(btn);
  if(data == 0) Serial.println("null");
  else Serial.println(data);
  delay(1000);

}