#define RELAY 5

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(RELAY, OUTPUT);
  //Serial.println(sizeof(bool));
}

bool relay = 0;

void loop() {
  // put your main code here, to run repeatedly:
  relay = relay ^ 1;
  digitalWrite(RELAY, relay);
  delay(500); // this speeds up the simulation
}