#define SENSOR A0
#define LED_COUNTS 10

const int LED[] = {2, 3, 4, 5, 6, 7,8,9,10,11};

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  while(!Serial);
  for(int idx = 0; idx < LED_COUNTS; ++idx) {
    pinMode(LED[idx], OUTPUT);
  }
}

void bar_led(int led_level) {
    for(int idx=0; idx < LED_COUNTS; ++idx) {
    if(idx < led_level) {
      digitalWrite(LED[idx], HIGH);
    } else {
      digitalWrite(LED[idx], LOW);
    }
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  int value = analogRead(SENSOR); // 0-1023 from range
  Serial.print("value is: ");
  Serial.println(value);
  int led_level = map(value,0, 1023, 0, LED_COUNTS);

  Serial.print("led level is: ");
  Serial.println(led_level);
  bar_led(led_level);

  delay(200);
}