#define led_pin 19
#define button_pin 16
int button_state=0;
void setup()
{
  pinMode(19, OUTPUT);
  pinMode(16, INPUT);
  Serial.begin(115200);
}
void loop()
{
  button_state=digitalRead(button_pin);
  if (button_state==LOW)
{
digitalWrite(led_pin, HIGH);
Serial.println("led ON");
}
else
{
  digitalWrite(led_pin, LOW);
  Serial.println("led OFF");
}
}