void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.write("\xa0\x01\x01\xa2"); // CHIUDE RELE
  delay(1000);
  Serial.write("\xa0\x01"); // APRE RELE
  Serial.write(0x00); // null terminates a string so it has to be sent on its own
  Serial.write(0xa1);
  delay(5000);
}