boolean led;
void setup()
{
led = true;
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(9600);
}
void loop()
{
if (led) {
digitalWrite(LED_BUILTIN, HIGH);
led = false;
Serial.println("LED ON");
} else {
digitalWrite(LED_BUILTIN, LOW);
led = true;
Serial.println("LED OFF");
}
delay(1000);
}