int btnPin=4;
int btnVal;
int dt=100;
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(btnPin,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  btnVal=digitalRead(btnPin);
  Serial.println(btnVal);
  delay(dt);
}