int sw = 8;
int led = 9;
void setup()
{
  Serial.begin(9600);
  pinMode(sm, INPUT_PULLUP);
  pinMode(led, OUTPUT);
}
void loop(){
  int val = digitalRead(sw);
  if(val==0){
    digitalWrite(led,1);
  }else{
    digitalWrite(led,0);;
  }
  delay(500);
}