boolean pushbutton; 
void setup() 
{
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(12, OUTPUT);
pinMode(4, INPUT_PULLUP); 

}

void loop() 
{
// put your main code here, to run repeatedly:
pushbutton=digitalRead(4);
Serial.println(pushbutton);

if( pushbutton == LOW)
{
digitalWrite(12,HIGH);
delay(00);
digitalWrite(12,LOW);
delay(500);
}
else
{
digitalWrite(12,LOW);
}

}