//sensor de ultrasonido
long u_tiempo(int trigger_pin, int echo_pin) {
  digitalWrite(trigger_pin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger_pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger_pin, LOW);
  long microseconds = pulseIn(echo_pin, HIGH);
  return microseconds;
}

long u_distancia(int trigger_pin, int echo_pin) {
  long microseconds = u_tiempo(trigger_pin, echo_pin);
  long u_distancia;
  u_distancia = microseconds / 29 / 2;
  if (u_distancia == 0) {
    u_distancia = 999;
  }
  return u_distancia;
}

//
//

#define PINUSTRIG 2
#define PINUSECHO 3

#define PINBUZZER 7

#define PINLEDA 9
#define PINLEDB 10
#define PINLEDC 11
#define PINLEDD 12

#define DISTANCIAARO 20

int distancia = 0;

int estadoled = 0;
int invertir = 0;
int recorridoled = PINLEDA;

int anotacion = 0;

void setup() {

  pinMode(PINUSTRIG, OUTPUT);
  pinMode(PINUSECHO, INPUT);

  pinMode(PINLEDA, OUTPUT);
  pinMode(PINLEDB, OUTPUT);
  pinMode(PINLEDC, OUTPUT);
  pinMode(PINLEDD, OUTPUT);

  pinMode(PINBUZZER, OUTPUT);

}


void loop() {

  distancia = u_distancia(PINUSTRIG, PINUSECHO);

  delay (100);

  while (distancia > DISTANCIAARO) {

    distancia = u_distancia(PINUSTRIG, PINUSECHO);

    if (invertir == 0) {

      digitalWrite(recorridoled, !invertir);
      digitalWrite((recorridoled - 1), invertir);
      recorridoled++;

    }

    else {

      digitalWrite(recorridoled, invertir);
      digitalWrite((recorridoled + 1), !invertir);
      recorridoled--;

    }

    if (recorridoled > PINLEDD) {
      invertir = 1;
      recorridoled = PINLEDD;
    }
    if (recorridoled < PINLEDA) {
      invertir = 0;
      recorridoled = PINLEDA;
    }

    delay (200);

  }

  for (anotacion = 0; anotacion <= 4; anotacion++) {

    if (anotacion == 0) {
      digitalWrite(PINBUZZER, HIGH);
    }

    else {
      digitalWrite(PINBUZZER, LOW);
    }

    estadoled = !estadoled;

    digitalWrite(PINLEDA, !estadoled);
    digitalWrite(PINLEDB, estadoled);
    digitalWrite(PINLEDC, !estadoled);
    digitalWrite(PINLEDD, estadoled);

    delay (500);

  }

  digitalWrite(PINLEDA, LOW);
  digitalWrite(PINLEDB, LOW);
  digitalWrite(PINLEDC, LOW);
  digitalWrite(PINLEDD, LOW);
  
}