const int ledPin = 6;
unsigned long previousMillis = 0;
const long interval = 1500;  // Intervalo de 1500ms para piscar
const long interval_1 = 100;  // Intervalo de piscada
bool flag1 = true;
void setup() {
  Serial.begin(9600);  // monitor serial
  pinMode(ledPin, OUTPUT);
  previousMillis = millis();
  digitalWrite(ledPin, LOW);
  luzEstrobo();
}
//-------------------------------------------------------------------
void loop() {
  if (millis() - previousMillis >= interval) {
    flag1 = true;
    previousMillis = millis();
    luzEstrobo();
  }
}
//-------------------------------------------------------------------
void luzEstrobo() {
  int pisca = 4;  //pisca 2 vezes
  while (flag1 == true) {
    for (int j = 0; j < pisca; ) {
      if (millis() - previousMillis >= interval_1) {
        digitalWrite(ledPin, !digitalRead(ledPin));
        previousMillis = millis();
        j++;
      }
    }
    flag1 = false;
  }
  previousMillis = millis();
}