const int trigPin = 3;
const int echoPin = 2;

const int leds[] = {8, 9, 10, 11, 12, 13};

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  for (int i = 0; i < 6; i++) {
    pinMode(leds[i], OUTPUT);
  }

  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);

  distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  int ledsToLight = 0;
  if (distance > 352) {
    ledsToLight = 6;
  } else if (distance > 298) {
    ledsToLight = 5;
  } else if (distance > 234) {
    ledsToLight = 4;
  } else if (distance > 183) {
    ledsToLight = 3;
  } else if (distance > 124) {
    ledsToLight = 2;
  } else if (distance > 73) {
    ledsToLight = 1;
  } else {
    ledsToLight = 0;
  }

  for (int i = 0; i < 6; i++) {
    if (i < ledsToLight) {
      digitalWrite(leds[i], HIGH);
    } else {
      digitalWrite(leds[i], LOW);
    }
  }

  delay(100);
}