练习古典吉他不用节拍器，容易节奏不稳
作为电子手工爱好者，DIY一个节拍器，练琴的积极性更高了。
准备材料：
- Arduino UNO主板一块
- 无源蜂鸣器 （或者8欧0.5W小喇叭一个）
- OLED 显示屏（SSD1306）
- 旋转编码器 （HW-040）
- B20K 电位器
- LED小灯珠4个
- 10K电阻4个
- 100欧电阻
- 面包板
- 杜邦线若干
连线方法：
metronome_work1.jpg
演示视频：
https://www.bilibili.com/video/BV1hM4y1a7Fh
代码：
需要从Arduino IDE下载一个BasicEncoder的库。（https://github.com/micromouseonline/BasicEncoder）
#include <Wire.h> //This is for i2C
#include <SSD1306Ascii.h> //i2C OLED库
#include <SSD1306AsciiWire.h> //i2C OLED库，GitHub开源可下载
#include <Encoder.h>
//https://github.com/micromouseonline/BasicEncoder
// i2C OLED
#define I2C_ADDRESS 0x3C
#define RST_PIN -1
SSD1306AsciiWire oled;
float OLEDTimer = 0; //屏幕刷新时间
int rhythm = 2; // 2/4拍 3/4 4/4
// Change these two numbers to the pins connected to your encoder.
// Best Performance: both pins have interrupt capability
// Good Performance: only the first pin has interrupt capability
// Low Performance: neither pin has interrupt capability
Encoder myEnc(3, 4);
// avoid using pins with LEDs attached
const byte switchPin = 2;
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978
int tonePin=A1;//蜂鸣器的pin
int PIN_LED0=8;
int PIN_LED1=10;
int PIN_LED2=11;
int PIN_LED3=13;
//旋转编码器引脚
int Encoder_OuputA=3;
int Encoder_OuputB=4;
int Encoder_Switch=2;
int Previous_Output;
int Encoder_Count;
bool bBreaked = false;
bool bSound = true;
void setup() {
// put your setup code here, to run once:
pinMode(tonePin,OUTPUT);//设置蜂鸣器的pin为输出模式
pinMode(PIN_LED0,OUTPUT);
pinMode(PIN_LED1,OUTPUT);
pinMode(PIN_LED2,OUTPUT);
pinMode(PIN_LED3,OUTPUT);
Serial.begin(115200);
pinMode(switchPin, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(switchPin), handleSwitch, RISING);
attachInterrupt(digitalPinToInterrupt(Encoder_OuputA), handleEncoder, CHANGE);
Serial.println("Encoder initalized");
// configure i2C
Wire.setClock(400000);
Wire.begin(); //start i2C
//------------------------------------------------------------------------------
//OLED 部分
#if RST_PIN >= 0
oled.begin(&Adafruit128x32, I2C_ADDRESS, RST_PIN);
#else // RST_PIN >= 0
oled.begin(&Adafruit128x32, I2C_ADDRESS);
#endif // RST_PIN >= 0
oled.setFont(Adafruit5x7);
oled.clear(); //clear display
oled.set2X(); //double-line font size - better to read it
oled.println("Metonome"); //print a welcome message
oled.println("Welcome"); //print a welcome message
delay(2000);
showRhythm();
}
long oldPosition = 0;
int bpm = 45; //每秒多少拍
void loop() {
int ledArray[] = {PIN_LED0,PIN_LED1,PIN_LED2,PIN_LED3};
long newPosition = myEnc.read();
if (newPosition != oldPosition && newPosition % 2 == 0) {
oldPosition = newPosition;
Serial.println(newPosition / 2);
bpm += newPosition / 2;
}
if(bBreaked)
showRhythm();
bBreaked = false;
if(bpm > 120)
bpm = 120;
if(bpm < 25)
bpm = 25;
// put your main code here, to run repeatedly:
float delayTime = 60*1000.0/bpm - (rhythm+2)*100;
Serial.println(delayTime);
for(int i=0;i<rhythm+2;i++)
{
if(bBreaked)
break;
closeAllLed();
digitalWrite(ledArray[i], HIGH);
if(bSound)
{
if(i==0)
{
tone(tonePin,NOTE_D5);
}
else
{
tone(tonePin,NOTE_D4);
}
delay(100);
noTone(tonePin);
}
for(int j=0;j<10;j++)
{
if(bBreaked)
break;
delay(delayTime/10);
}
}
}
void closeAllLed()
{
digitalWrite(PIN_LED0, LOW);
digitalWrite(PIN_LED1, LOW);
digitalWrite(PIN_LED2, LOW);
digitalWrite(PIN_LED3, LOW);
}
void handleEncoder()
{
Serial.println("encoder changed");
bBreaked = true;
}
void handleSwitch() {
Serial.println("Switch pressed");
rhythm ++;
if(rhythm == 3 )
{
rhythm = 0;
}
bBreaked = true;
}
void showRhythm()
{
oled.clear(); //clear display
oled.set2X(); //double-line font size - better to read it
oled.println("Metonome!"); //print a welcome message
String strInfo;
switch(rhythm)
{
case 0:
strInfo = "2/4 BPM:";
break;
case 1:
strInfo = "3/4 BPM:";
break;
case 2:
strInfo = "4/4 BPM:";
break;
default:
oled.println("Err");
break;
}
String str = strInfo + bpm;
oled.println(str);
}
