int Trigger = 2;
int Echo = 3;

int led1 = 4;
int led2 = 5;
int led3 = 6;

void setup() {
  Serial.begin(9600);
  pinMode(Trigger, OUTPUT);
  pinMode(Echo, INPUT);
  digitalWrite(Trigger, LOW);

  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
}

void loop(){
  int t;
  int d;

  digitalWrite(Trigger, HIGH);
  delay(10);
  digitalWrite(Trigger,LOW);

  t = pulseIn(Echo, HIGH);
  d = t/59;

  if (d >= 15) {
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
  }

  if (d >= 10 && d < 15) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
  }

  if (d >= 5 && d < 10) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
  }

  if (d < 5) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, HIGH);
  }

  Serial.print("Distancia: ");
  Serial.print(d);
  Serial.print(" cm");
  Serial.println();
  delay(500);
}