int buttonPin = 2;
int LED = 13;
int buttonState;
int lastButtonState = LOW;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup() 
{
 pinMode(buttonPin, INPUT);
 pinMode(LED,OUTPUT);
 Serial.begin(9600);
}

void loop() 
{
   if (digitalRead(buttonPin) != lastButtonState) 
     {
      lastDebounceTime = millis();  // reset the debouncing timer
     }
 
   if ((millis() - lastDebounceTime) > debounceDelay) 
     { 
       if (digitalRead(buttonPin) != buttonState) 
         {
           buttonState = digitalRead(buttonPin);
           if (buttonState == HIGH) 
             {
               digitalWrite(LED,HIGH);
               Serial.println("Press & Led ON ");
             }
         }
     }
}