const int buttonPin = 8;
const int ledPin = 9;
int buttonState;
int dt = 100;
void setup() {
  Serial.begin(9600);
  pinMode(buttonPin , INPUT);
  pinMode(ledPin, OUTPUT );

}
void loop() {
buttonState = digitalRead(buttonPin);
Serial.println("button State = ");
Serial.println(buttonState);

if(buttonState == LOW)
{
  Serial.println("Button is NOT PRESSED");
  digitalWrite(ledPin, LOW);
}
else
{
  Serial.println("Button is PRESSED");
   digitalWrite(ledPin, HIGH);
}
delay(dt);  //debounce
}