int cathode = 9, anode= 2 ;
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(cathode, OUTPUT);
pinMode(anode, OUTPUT);
}

void loop() {
Serial.print("Nyala,");
digitalWrite(cathode, LOW);
digitalWrite(anode, HIGH);
delay(3000);
Serial.print("Mati,");
digitalWrite(cathode, HIGH);
digitalWrite(anode, LOW);
delay(3000);
}