问为什么这个代码不能工作，使用arduino uno，一个sr04超声波传感器和9个leds？

EN

const int trigPin = 13;
const int echoPin = 12;
const int maxRange = 300;
const int minRange = 0;
const int delayTime = 300;
const int ledPins[] = {10, 9, 8, 7 ,6, 5, 4, 3, 2};
const int ledCount = 9;

void setup() {
    Serial.begin (9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    for(int thisLed = 0; thisLed < ledCount; thisLed = thisLed++){
        pinMode(ledPins[thisLed], OUTPUT); 
    }
}

void loop() {
    long duration;

    digitalWrite(trigPin, LOW);        // this alinea triggers the sensor
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH);  // stores lenght of returned pulse

    long distance = duration/58.2;

    if (distance > maxRange){
        Serial.println("Out of range");
        delay(delayTime);
    }
    else if (distance < minRange){
        Serial.println("Out of range");
        delay(delayTime);
    }
    else {
        Serial.print(distance);
        Serial.println(" cm");      
        delay(delayTime);
    }

    constrain(distance, minRange, maxRange);
    int usedLed = map(distance, minRange, maxRange, 0, ledCount);

    for(int thisLed = 0; thisLed < usedLed; thisLed++){
        digitalWrite(ledPins[thisLed], HIGH); 
    } 
}