/* Relay Module — kontrol lampu AC 220V */ const int relayPin = 8;   // pin sinyal relay void setup() {  pinMode(relayPin, OUTPUT);  digitalWrite(relayPin, LOW);   // relay OFF} void loop() {  digitalWrite(relayPin, HIGH);  // relay ON → lampu nyala  delay(1000);                     // tunggu 1 detik  digitalWrite(relayPin, LOW);   // relay OFF → lampu mati  delay(1000);                     // tunggu 1 detik}