Relais Module 12v AC250V 10A Relais 12v 1 relais LED indicator

// Canonical example for a 12V relay module with indicator LED
// Wiring:
// Arduino 5V  -> DC+
// Arduino GND -> DC-
// Arduino D7  -> IN

const int RELAY_PIN = 7;

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("12V relay module example starting...");
}

void loop() {
  // Many relay modules are active LOW, but some are active HIGH.
  // This example toggles both states with delays so you can observe the relay.

  Serial.println("Relay ON");
  digitalWrite(RELAY_PIN, LOW);   // common active-LOW trigger
  delay(2000);

  Serial.println("Relay OFF");
  digitalWrite(RELAY_PIN, HIGH);
  delay(2000);
}