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Arduino鬼畜电子琴制作

由于某些原因，我又拿出了我的Arduino开发板，这次准备制作一个完整的电子琴。没有意外的话，这应该是我最后一次做Arduino了。

正式开始前的准备

明确需求

  1. 能演奏基本音符
  2. 能演奏高低音
  3. 能通过显示设备输出当前音符
  4. 能够自动演奏

硬件准备

开发板

这次仍然采用经典的 Arduino Uno 开发板，相关说明在我之前的博客中有提及，这里不做描述。

发声设备

为便于研究(lan)，这次采用的是无源蜂鸣器作为发声设备，同样，我在之前博客中有提及，这里不描述。

显示设备

我的显示设备采用LCD 1602，使用spi接口，可以大幅降低成本（但会占用大量GPIO）
LCD 1602

其他

  1. 杜邦线若干（众所周知，杜邦线是会自己消失的 /确信）
  2. 适量面包板
  3. 10个10k欧电阻（用于制作下拉电路）
  4. 11个按键

制作

绘制电路图

工具

我使用fritzing制作电路图

LCD1602接线

为节约GPIO，我采用四线接法，为方便接线，我把六根线全挂在An GPIO上面，接线表如下

LCD1602 PIN
VSS GND
VDD 5V
V0 电位器中间引脚
RS A0
RW GND
E A1
D0 /
D1 /
D2 /
D3 /
D4 A2
D5 A3
D6 A4
D7 A5
A 5V
K GND

关于开关按键的电路

经过我的多次实践发现，若按键直接接INPUT接口，且开发板上接有无源蜂鸣器，会出现按键莫名改变状态的问题。
经过约一周的收集资料及咨询大佬，终于发现了问题。
问题关键是INPUT接口的高低电平不确定。目前存在两种解决方案：

  1. 设置芯片INPUT接口内部上拉
  2. 在按键外部部分设置外部下拉电路
方案一 内部上拉

故名思意，内部上拉，就是在芯片内部将这个GPIO的电平调至高电平，先不管芯片内部是怎么实现的这一功能，对于我们来说，这个功能只需要一行代码就能解决，所以这是最简单的解决方案。
代码说明：
原来的INPUT接口初始化代码如下

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pinMode(11, INPUT);

我们现在要将其改为

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pinMode(11, INPUT_PULLUP);

即可实现内部上拉。
但因为我可能在某宝买到了假的Uno开发板，我没能实现内部上拉，所以我选择了外部下拉。

方案二 外部下拉

既然是外部，电路自然不同，原本的开关电路将要改成下图样式
外部下拉电路简图
以咱可怜的高中物理水平就不强行解释这个电路原理了（

成果图

成果电路图

采购元件

这里推荐淘宝上的优信电子

代码部分

我需要先定义各个音符及其高低音的发声频率

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#define Do_l 262
#define re_l 294
#define mi_l 330
#define fa_l 349
#define so_l 392
#define la_l 440
#define si_l 494
#define Do 523
#define re 587
#define mi 659
#define fa 698
#define so 784
#define la 880
#define si 932
#define Do_h 1046
#define re_h 1175
#define mi_h 1318
#define fa_h 1397
#define so_h 1568
#define la_h 1760
#define si_h 1976

然后开始制作标准音及混音发声
目前我找到了一个很难受的土制混音方案，就是每隔一毫秒换一次音，缺点就是声音很沙哑，有点抖。
为实现无限叠加混音，我使用了如下代码

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while (1) {
  int normalTones[8] = {};
  int num = 0;
  //get button state
  button0 = digitalRead(2);
  button1 = digitalRead(3);
  button2 = digitalRead(4);
  button3 = digitalRead(5);
  button4 = digitalRead(6);
  button5 = digitalRead(7);
  button6 = digitalRead(8);
  button7 = digitalRead(9);
  button8 = digitalRead(10);
  button9 = digitalRead(11);
  if (button0 == HIGH) {
    normalTones[num] = Do;
    num++;
  }
  if (button1 == HIGH) {
    normalTones[num] = re;
    num++;
  }
  if (button2 == HIGH) {
    normalTones[num] = mi;
    num++;
  }
  if (button3 == HIGH) {
    normalTones[num] = fa;
    num++;
  }
  if (button4 == HIGH) {
    normalTones[num] = so;
    num++;
  }
  if (button5 == HIGH) {
    normalTones[num] = la;
    num++;
  }
  if (button6 == HIGH) {
    normalTones[num] = si;
    num++;
  }
  normalTones[num] = 0;
  if (num == 0) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Welcome!        ");
  }
  else if (num == 1) {
    if (normalTones[0] == Do) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Do (C)          ");
    }
    else if (normalTones[0] == re) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Re (D)          ");
    }
    else if (normalTones[0] == mi) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Mi (E)          ");
    }
    else if (normalTones[0] == fa) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Fa (F)          ");
    }
    else if (normalTones[0] == so) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("So (G)          ");
    }
    else if (normalTones[0] == la) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("La (A)          ");
    }
    else if (normalTones[0] == si) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Si (B)          ");
    }
  }
  else{
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("MIX             ");
  }
  for (int i = 0; i < 8; i++) {
    if (normalTones[i] == 0) break;
    tone(13, normalTones[i]);
    delay(1);
  }
  if (num == 0) break;
}

这里说明一下几个函数

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lcd.setCursor(0, 1);//设置打印字符光标位置为第二行第一个
lcd.print();//打印括号内的字符
delay(1);//延时1ms
tone();//发声函数，需要传递两个参数，一个参数为发声脚，一个为频率
digitalRead();//获取按键状态，当被按下时为HIGH

完整代码

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#include <LiquidCrystal.h>
/*
This programme was produced by Lakphy.
It is prohibited to use these code for illegal purposes.
Welcome to visit the private site of Lakphy:
International channel: lakphy.me
        China channel: lakphy.gitee.io
                Email: [email protected]
Thanks for the help of the seniors of SAST !
Thanks for open source ! 
*/
#define Do_l 262
#define re_l 294
#define mi_l 330
#define fa_l 349
#define so_l 392
#define la_l 440
#define si_l 494
#define Do 523
#define re 587
#define mi 659
#define fa 698
#define so 784
#define la 880
#define si 932
#define Do_h 1046
#define re_h 1175
#define mi_h 1318
#define fa_h 1397
#define so_h 1568
#define la_h 1760
#define si_h 1976
// vss   vcc   v0   rs   rw   e   db0   db1   db2   db3   db4   db5   db6   db7   led+   led-
//                  a0        a1  \     \     \     \     A2    A3    A4    A5
int button0 = LOW;
int button1 = LOW;
int button2 = LOW;
int button3 = LOW;
int button4 = LOW;
int button5 = LOW;
int button6 = LOW;
int button7 = LOW;
int button8 = LOW;
int button9 = LOW;
LiquidCrystal lcd(A0, A1, A2, A3, A4, A5);
int music[] = {
  so_l, so_l, la_l, so_l, Do  , si_l,
  so_l, so_l, la_l, so_l, re  , Do  ,
  so_l, so_l, so  , mi  , Do  , si_l, so_l,
  fa  , fa  , mi  , Do  , re  , Do
};
int times[] = {
  200, 200, 400, 400, 400, 800,
  200, 200, 400, 400, 400, 800,
  400, 400, 400, 400, 400, 400, 400,
  400, 200, 400, 400, 400, 800
};
void setup() {
  // setup lcd
  lcd.begin(16, 2);
  lcd.print("Lakphy Singer :)");
  lcd.setCursor(0, 1);
  lcd.print("Hello!          ");
  // setup keyboard
  pinMode(2, INPUT);
  pinMode(3, INPUT);
  pinMode(4, INPUT);
  pinMode(5, INPUT);
  pinMode(6, INPUT);
  pinMode(7, INPUT);
  pinMode(8, INPUT);
  pinMode(9, INPUT);
  pinMode(10, INPUT);
  pinMode(11, INPUT);
  //setup tones
  pinMode(13, OUTPUT);
  noTone(13);
}

void loop() {
  bool canRun = 1;
  //get button state
  button0 = digitalRead(2);
  button1 = digitalRead(3);
  button2 = digitalRead(4);
  button3 = digitalRead(5);
  button4 = digitalRead(6);
  button5 = digitalRead(7);
  button6 = digitalRead(8);
  button7 = digitalRead(9);
  button8 = digitalRead(10);
  button9 = digitalRead(11);

  //high
  if (button7 == HIGH) {

    if (button0 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Do_h (C)        ");
      //sing
      tone(13, Do_h);
      delay(50);
      while (1) {
        if (digitalRead(2) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //re
    if (button1 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Re_h (D)        ");
      tone(13, re_h);
      delay(50);
      while (1) {
        if (digitalRead(3) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //mi
    if (button2 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Mi_h (E)        ");
      tone(13, mi_h);
      delay(50);
      while (1) {
        if (digitalRead(4) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //fa
    if (button3 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Fa_h (F)        ");
      tone(13, fa_h);
      delay(50);
      while (1) {
        if (digitalRead(5) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //so
    if (button4 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("So_h (G)        ");
      tone(13, so_h);
      delay(50);
      while (1) {
        if (digitalRead(6) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //la
    if (button5 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("La_h (A)        ");
      tone(13, la_h);
      delay(50);
      while (1) {
        if (digitalRead(7) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //si
    if (button6 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Si_h (B)        ");
      tone(13, si_h);
      delay(50);
      while (1) {
        if (digitalRead(8) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
  }

  //low
  else if (button8 == HIGH) {

    if (button0 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Do_l (C)        ");
      //sing
      tone(13, Do_l);
      delay(50);
      while (1) {
        if (digitalRead(2) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //re
    if (button1 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Re_l (D)        ");
      tone(13, re_l);
      delay(50);
      while (1) {
        if (digitalRead(3) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //mi
    if (button2 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Mi_l (E)        ");
      tone(13, mi_l);
      delay(50);
      while (1) {
        if (digitalRead(4) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //fa
    if (button3 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Fa_l (F)        ");
      tone(13, fa_l);
      delay(50);
      while (1) {
        if (digitalRead(5) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //so
    if (button4 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("So_l (G)        ");
      tone(13, so_l);
      delay(50);
      while (1) {
        if (digitalRead(6) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //la
    if (button5 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("La_l (A)        ");
      tone(13, la_l);
      delay(50);
      while (1) {
        if (digitalRead(7) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
    //si
    if (button6 == HIGH) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Si_l (B)        ");
      tone(13, si_l);
      delay(50);
      while (1) {
        if (digitalRead(8) != HIGH) break;
        delay(10);
      }
      noTone(13);
    }
  }
  else if (button9 == HIGH) {
    if (canRun) {
      //lcd print
      lcd.setCursor(0, 1);
      lcd.print("Auto Singing....");
      for (int x = 0; x < 25; x++)
      {
        if (!canRun) break;
        if (music[x] == 0) {
          noTone(13);
        }
        else {
          tone(13, music[x]);
        }
        delay(times[x]);//节拍延时
        //digitalWrite(ledpin,LOW);
        noTone(13);
      }
      canRun = 0;
    }
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Singing END !   ");
  }
  //
  //
  //
  //normal tone
  /*
    //Do
    else if (button0 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Do (C)          ");
    //sing
    tone(13, Do);
    delay(50);
    while (1) {
      if (digitalRead(2) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //re
    else if (button1 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Re (D)          ");
    tone(13, re);
    delay(50);
    while (1) {
      if (digitalRead(3) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //mi
    else if (button2 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Mi (E)          ");
    tone(13, mi);
    delay(50);
    while (1) {
      if (digitalRead(4) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //fa
    else if (button3 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Fa (F)          ");
    tone(13, fa);
    delay(50);
    while (1) {
      if (digitalRead(5) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //so
    else if (button4 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("So (G)          ");
    tone(13, so);
    delay(50);
    while (1) {
      if (digitalRead(6) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //la
    else if (button5 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("La (A)          ");
    tone(13, la);
    delay(50);
    while (1) {
      if (digitalRead(7) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
    //si
    else if (button6 == HIGH) {
    //lcd print
    lcd.setCursor(0, 1);
    lcd.print("Si (B)          ");
    tone(13, si);
    delay(50);
    while (1) {
      if (digitalRead(8) != HIGH) break;
      delay(10);
    }
    noTone(13);
    }
  */
  else {
    while (1) {
      int normalTones[8] = {};
      int num = 0;
      //get button state
      button0 = digitalRead(2);
      button1 = digitalRead(3);
      button2 = digitalRead(4);
      button3 = digitalRead(5);
      button4 = digitalRead(6);
      button5 = digitalRead(7);
      button6 = digitalRead(8);
      button7 = digitalRead(9);
      button8 = digitalRead(10);
      button9 = digitalRead(11);
      if (button0 == HIGH) {
        normalTones[num] = Do;
        num++;
      }
      if (button1 == HIGH) {
        normalTones[num] = re;
        num++;
      }
      if (button2 == HIGH) {
        normalTones[num] = mi;
        num++;
      }
      if (button3 == HIGH) {
        normalTones[num] = fa;
        num++;
      }
      if (button4 == HIGH) {
        normalTones[num] = so;
        num++;
      }
      if (button5 == HIGH) {
        normalTones[num] = la;
        num++;
      }
      if (button6 == HIGH) {
        normalTones[num] = si;
        num++;
      }
      normalTones[num] = 0;
      if (num == 0) {
        //lcd print
        lcd.setCursor(0, 1);
        lcd.print("Welcome!        ");
      }
      else if (num == 1) {
        if (normalTones[0] == Do) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("Do (C)          ");
        }
        else if (normalTones[0] == re) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("Re (D)          ");
        }
        else if (normalTones[0] == mi) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("Mi (E)          ");
        }
        else if (normalTones[0] == fa) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("Fa (F)          ");
        }
        else if (normalTones[0] == so) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("So (G)          ");
        }
        else if (normalTones[0] == la) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("La (A)          ");
        }
        else if (normalTones[0] == si) {
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("Si (B)          ");
        }
      }
      else{
          //lcd print
          lcd.setCursor(0, 1);
          lcd.print("MIX             ");
      }
      for (int i = 0; i < 8; i++) {
        if (normalTones[i] == 0) break;
        tone(13, normalTones[i]);
        delay(1);
      }
      if (num == 0) break;
    }
  }

  //delay
  noTone(13);
}

成品图

成品图