int sw = 15;
int led = 4;
int bs = 0;
void setup()
{
  Serial.begin(115200);
  pinMode(sw,INPUT);
  pinMode(led,OUTPUT);
}
void loop()
{
  bs=digitalRead(sw);
  Serial.println("statu=");
  Serial.print(bs);
  delay(500);
  if(bs == HIGH)
  {
    digitalWrite(led,HIGH);

  }
  else{
    digitalWrite(led,LOW);
  }
}