int data;

void setup() { 
  Serial.begin(9600); //initialize serial COM at 9600 baudrate
  pinMode(LED_BUILTIN, OUTPUT); //make the LED pin (13) as output
  digitalWrite (LED_BUILTIN, LOW);
  
  Serial.println("Hi!, I am Arduino");
}
 
void loop() {
while (Serial.available()){
  data = Serial.read();
}

if (data == '1')
digitalWrite (LED_BUILTIN, HIGH);

else if (data == '0')
digitalWrite (LED_BUILTIN, LOW);

}