int leds[] = {8, 9, 10, 11, 12, 13}; 
int numLEDs = 6; 
int trigPin = 3; 
int echoPin = 2; 
long duration; 
int distance; 

void setup() { 
    pinMode(trigPin, OUTPUT); 
    pinMode(echoPin, INPUT); 
    for (int i = 0; i < numLEDs; 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 / 6; 

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

    int activeLEDs = map(distance, 0, 100, 0, numLEDs); 
    for (int i = 0; i < numLEDs; i++) { 
        if (i < activeLEDs) { 
            digitalWrite(leds[i], HIGH); 
        } else { 
            digitalWrite(leds[i], LOW); 
        } 
    } 
    delay(100); 
}