#define trig 3
#define echo 4

int leds[] = {8, 9, 10, 11, 12, 13};
int LEDs = 6; 
long duration;
int distance;

void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  for (int i = 0; i < LEDs; i++) {
    pinMode(leds[i], OUTPUT); 
  }
  Serial.begin(9600);
}

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

  
  duration = pulseIn(echo, HIGH);

  
  distance = duration * 0.034 / 2;

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

 
  int activeLEDs = map(distance, 0, 397, 0, LEDs);

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

  delay(100); 
}