/**
   Mini piano for Arduino.

   You can control the colorful buttons with your keyboard:
   After starting the simulation, click anywhere in the diagram to focus it.
   Then press any key between 1 and 8 to play the piano (1 is the lowest note,
   8 is the highest).

   Copyright (C) 2021, Uri Shaked. Released under the MIT License.
*/

#include "pitches.h"

#define SPEAKER_PIN 8

const uint8_t buttonPins[] = { 12,11,10,9,7,6,5,4 }; //定义一个各琴键所接开发板接口的数组；
const int buttonTones[] = {
  NOTE_C4,  NOTE_D4,  NOTE_E4,  NOTE_F4, 
   NOTE_G4,  NOTE_A4,  NOTE_B4,  NOTE_C5
}; //定义各琴键所对应的音调值（名称）的数组

const int numTones =sizeof(buttonPins) / sizeof(buttonPins[0]); //声明一个整型变量，赋值为接口数组总内存除以单个成员内存即数组长度

void setup() {
  for(uint8_t i=0 ; i<numTones ; i++){
    pinMode(buttonPins[i],INPUT_PULLUP);
  }
       //琴键是input_pullup 模式，for循环设置好
  pinMode(SPEAKER_PIN, OUTPUT);
} //初始化函数中设置每个接口的信息模式- 输入还是输出

void loop() {
  int pitch=0;//定义一个当前音调的变量 pitch

  for (uint8_t i = 0; i <numTones ; i++) { //遍历所有琴键去搜索谁、哪个被摁下去（是低电平）
    if (digitalRead(buttonPins[i]) == LOW){ //数字化读出当前i号接口成员的电平
      
      pitch = buttonTones[i]; //赋值当前音调pitch为低电平的那个琴键对应的音调值（音调数组里面相应的成员）；

    } 
  }
  if (pitch) {
    tone(SPEAKER_PIN,pitch);
     //在SPEAKER_PIN这个蜂鸣器接口上播放当前音调pitch
  } else {
    noTone(SPEAKER_PIN);
      //pitch为空的话，就静音。
  }
}