// Relay Demonstration
//
// 17 May 2024, by Koepel, Public Domain.

// The pins for the relay modules.
const int relay1Pin = D2;

void setup() 
{
  // Set pins as output.
  pinMode(relay1Pin, OUTPUT);
  delay(1000);
}

void loop() 
{
  // Activate the relays one by one for one second.
  // The relay module simulates a module that
  // is activated with a high level at the "IN" pin.
  digitalWrite(relay1Pin,HIGH); // Activate relay.
  delay(1000);
  digitalWrite(relay1Pin,LOW);  // Release the relay.
  delay(1000);
}