UNO R4 TUTORIAL2(DACwithPassiveBuzzer,)

active buzzerは内部に発振をそなえ単純なブザー機能をもつ　メロディ可能なるも音ひどい

passive buzzerは外部電圧で発振するのでメロディが可能（±逆でも音がでる）

https://www.denshi.club/cookbook/arduino/r4/10-2-d-a.htmlを参考に

https://cediablog.com/arduinor4-minima-dac/を修正

#include "analogWave.h"

analogWave wave(DAC);

#define NOTE_A4 69 // MIDI note value for middle A

#define FREQ_A4 440 // frequency for middle A

// the tonic, or first note of the key signature for the song:

int tonic = 65;

// the melody sequence. Note values are relative to the tonic:

int melody[] = {1, 3, 5, 1,

1, 3, 5, 1,

5, 6, 8, 5, 6, 8,

8, 10, 8, 6, 5, 1,

8, 10, 8, 6, 5, 1,

1, -4, 1,

1, -4, 1

};

// the rhythm sequence. Values are 1/note, e.g. 4 = 1/4 note:

int rhythm[] = {4, 4, 4, 4,

4, 4, 4, 4,

4, 4, 2,

4, 4, 2,

8, 8, 8, 8, 4, 4,

8, 8, 8, 8, 4, 4,

4, 4, 2,

4, 4, 2

};

// which note of the melody to play:

int noteCounter = 0;

int bpm = 120; // beats per minute

// duration of a beat in ms

float beatDuration = 60.0 / bpm * 1000;

void setup() {

// start the sine wave generator:

wave.sine(10);

}

void loop() {

// current note is an element of the array:

int currentNote = melody[noteCounter] + tonic;

// play a note from the melody:

// convert MIDI note number to frequency:

float frequency = FREQ_A4 * pow(2, ((currentNote - NOTE_A4) / 12.0));

// all the notes in this are sixteenth notes,

// which is 1/4 of a beat, so:

float noteDuration = beatDuration * (4.0 / rhythm[noteCounter]);

// turn the note on:

wave.freq(frequency);

// tone(speakerPin, frequency, noteDuration * 0.85);

// keep it on for the appropriate duration:

delay(noteDuration * 0.85);

wave.stop();

delay(noteDuration * 0.15);

// turn the note off:

// noTone(speakerPin);

// increment the note number for next time through the loop:

noteCounter++;

// keep the note in the range from 0 – 32 using modulo:

noteCounter = noteCounter % 32;

}