int red=12;
int yellow= 13;

void setup()
{
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  Serial.begin(9600);

}
void loop()
{
  digitalWrite(red, HIGH);
  digitalWrite(yellow, LOW);

  Serial.println("my led is on");
  delay(1000);
  Serial.println("my led is off");
  digitalWrite(red, LOW);
  digitalWrite(yellow, HIGH);
  delay(1000);
  
}