const int relay = 5; void setup() { Serial.begin(115200); pinMode(relay, OUTPUT); } void loop() { // Normally Open configuration, send LOW signal to let current flow // (if you're usong Normally Closed configuration send HIGH signal) digitalWrite(relay, LOW); Serial.println("Current Flowing"); delay(5000); // Normally Open configuration, send HIGH signal stop current flow // (if you're usong Normally Closed configuration send LOW signal) digitalWrite(relay, HIGH); Serial.println("Current not Flowing"); delay(5000); }