/*  這是註解
  LED bar graph

  https://wokwi.com/arduino/projects/309829489359061570

  Turns on a series of LEDs based on the value of an analog sensor.
  This is a simple way to make a bar graph display. Though this graph uses 10
  LEDs, you can use any number by changing the LED count and the pins in the
  array.

  This method can be used to control any series of digital outputs that depends
  on an analog input.

  The circuit:
  - LEDs from pins 2 through 11 to ground

  created 4 Sep 2010
  by Tom Igoe

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/BarGraph
*/

// these constants won't change:
const int analogPin = A0;   // the pin that the potentiometer is attached to 【滑動電阻輸入】
const int ledCount = 10;    // the number of LEDs in the bar graph 【LED的數量】

int ledPins[] = {
  2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};   // an array of pin numbers to which LEDs are attached  【LED 連接輸出】


void setup() {
  // loop over the pin array and set them all to output:  【宣告LED 接腳輸出】
  for (int thisLed = 0; thisLed < ledCount; thisLed++) {
    pinMode(ledPins[thisLed], OUTPUT);
  }
}

void loop() {
  // read the potentiometer:  【讀取滑動電阻的位置】
  int sensorReading = analogRead(analogPin);
  // map the result to a range from 0 to the number of LEDs:【將讀取的值對應到10個LED裡】
  int ledLevel = map(sensorReading, 0, 1023, 0, ledCount);

  // loop over the LED array:  【依照滑動電阻的位置點亮 LED燈】
  for (int thisLed = 0; thisLed < ledCount; thisLed++) {
    // if the array element's index is less than ledLevel,
    // turn the pin for this element on:
    if (thisLed < ledLevel) {
      digitalWrite(ledPins[thisLed], HIGH);
    }
    // turn off all pins higher than the ledLevel:
    else {
      digitalWrite(ledPins[thisLed], LOW);
    }
  }
}