#define pinSET 18

long Timer_Startup = 0;
const long Period_Startup = 10000;

long Timer_Active = 0;
const long Period_Active = 3000;

bool isActive = false;

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  pinMode(pinSET, OUTPUT);
  digitalWrite(pinSET, LOW);
}

void loop() {
  if ((Timer_Startup == 0) or (millis() > Timer_Startup + Period_Startup)) {
    Timer_Startup = millis();
    Timer_Active = Timer_Startup;
    digitalWrite(pinSET, HIGH);
    isActive = true;
    Serial.println("SET ON"); 
  }

  if ((isActive == true) and (millis() > Timer_Active + Period_Active)) {
    digitalWrite(pinSET, LOW);
    isActive = false;
    Serial.println("SET OFF"); 
  }

  delay(1000);
  Serial.println("."); 
  
}