#define trigPin 7
#define echoPin 6
#define led0 8
#define led1 9
#define led2 10
#define led3 11

void setup () {
  Serial.begin (9600);
  pinMode (trigPin, OUTPUT);
  pinMode (echoPin, INPUT) ;

  pinMode(led0, OUTPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  
}

void loop () {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delay(2);
  digitalWrite(trigPin, HIGH);
  delay(10);
  digitalWrite(tigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;

  if (distante >=16)
  {
    digitalWrite(led0, HIGH);
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
  }
  else {
    digitalWrite(led0,LOW);
  }

   if (distante <=15){
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
  }
    if (distante <10){
    digitalWrite(led1, LOW);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
  }
     if (distante <5){
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, HIGH);
  }

  delay(500);
  }