nyan_cat.ino

#include "math.h"

const char nyan_cat_intro[] = "DS5,16,E5,16,FS5,8,B5,8,DS5,16,E5,16,FS5,16,B5,16,CS6,16,DS6,16,CS6,16,AS5,16,B5,8,FS5,8,DS5,16,E5,16,FS5,8,B5,8,CS6,16,AS5,16,B5,16,CS6,16,E6,16,DS6,16,E6,16,B5,16\n";
const char nyan_cat_melody[] = "FS5,8,GS5,8,DS5,16,DS5,16,R,16,B4,16,D5,16,CS5,16,B4,16,R,16,B4,8,CS5,8,D5,8,D5,16,CS5,16,B4,16,CS5,16,DS5,16,FS5,16,GS5,16,DS5,16,FS5,16,CS5,16,DS5,16,B4,16,CS5,16,B4,16,DS5,8,FS5,8,GS5,16,DS5,16,FS5,16,CS5,16,DS5,16,B4,16,D5,16,DS5,16,D5,16,CS5,16,B4,16,CS5,16,D5,8,B4,16,CS5,16,DS5,16,FS5,16,CS5,16,DS5,16,CS5,16,B4,16,CS5,8,B4,8,CS5,8,FS5,8,GS5,8,DS5,16,DS5,16,R,16,B4,16,D5,16,CS5,16,B4,16,R,16,B4,8,CS5,8,D5,8,D5,16,CS5,16,B4,16,CS5,16,DS5,16,FS5,16,GS5,16,DS5,16,FS5,16,CS5,16,DS5,16,B4,16,CS5,16,B4,16,DS5,8,FS5,8,GS5,16,DS5,16,FS5,16,CS5,16,DS5,16,B4,16,D5,16,DS5,16,D5,16,CS5,16,B4,16,CS5,16,D5,8,B4,16,CS5,16,DS5,16,FS5,16,CS5,16,DS5,16,CS5,16,B4,16,CS5,8,B4,8,CS5,8,B4,8,FS4,16,GS4,16,B4,8,FS4,16,GS4,16,B4,16,CS5,16,DS5,16,B4,16,E5,16,DS5,16,E5,16,FS5,16,B4,8,B4,8,FS4,16,GS4,16,B4,16,FS4,16,E5,16,DS5,16,CS5,16,B4,16,FS4,16,DS4,16,E4,16,FS4,16,B4,8,FS4,16,GS4,16,B4,8,FS4,16,GS4,16,B4,16,B4,16,CS5,16,DS5,16,B4,16,FS4,16,GS4,16,FS4,16,B4,8,B4,16,AS4,16,B4,16,FS4,16,GS4,16,E4,16,E5,16,DS5,16,E5,16,FS5,16,B4,8,AS4,8,B4,8,FS4,16,GS4,16,B4,8,FS4,16,GS4,16,B4,16,CS5,16,DS5,16,B4,16,E5,16,DS5,16,E5,16,FS5,16,B4,8,B4,8,FS4,16,GS4,16,B4,16,FS4,16,E5,16,DS5,16,CS5,16,B4,16,FS4,16,DS4,16,E4,16,FS4,16,B4,8,FS4,16,GS4,16,B4,8,FS4,16,GS4,16,B4,16,B4,16,CS5,16,DS5,16,B4,16,FS4,16,GS4,16,FS4,16,B4,8,B4,16,AS4,16,B4,16,FS4,16,GS4,16,B4,16,E5,16,DS5,16,E5,16,FS5,16,B4,8,CS5,8\n";
String nyan_song = String(nyan_cat_melody);

char inputStr[2048];

char* note;
char* duration;
int bpm = 110;


void setup() {
    pinMode(D0, OUTPUT);
    
        nyan_song.toCharArray(inputStr, nyan_song.length());
    note = strtok(inputStr,",");
    duration = strtok(NULL,", \n");
}

void loop() {
    //tone(D0, 220, 500);
 
    playNote(note, atoi(duration));   
 
            if (duration != NULL) {
                // advance the note
                note = strtok(NULL,",");
                duration = strtok(NULL,", \n");
            }
            else {
                nyan_song.toCharArray(inputStr, nyan_song.length());
                note = strtok(inputStr,",");
                duration = strtok(NULL,", \n");
            }
            
   // delay(1000);
}

void playNote(String note, int duration) {

    int noteNum = 0;
    int noteSharp = 0;
    int noteFlat = 0;
    int octave = 5;
    int freq = 256;

    int octIndex = note.length()-1; // octave is the last char
    String tempOctave = note.substring(octIndex, octIndex+1);
    octave = tempOctave.toInt();
    String tempNote = note.substring(0, octIndex);
    tempNote.toUpperCase();
    if (tempNote.length()==2) {
        if (tempNote.charAt(1)=='S' || tempNote.charAt(1)=='#') {
            noteSharp = 1;
        } else if (tempNote.charAt(1)=='B') {
            noteFlat = 1;
        }
    }

    // Using 240 instead of 250 after calibrating at 60 BPM and 240 BPM with a stopwatch.
    // Seems to work well with and without Serial logging, so that is ok to leave uncommented below.
    if (duration != 0) {
        duration = 1000*240/bpm/duration;
    }

    switch (tempNote.charAt(0)) {
        case 'C':
            noteNum = 0 + noteSharp;
            break;
        case 'D':
            noteNum = 2 + noteSharp - noteFlat;
            break;
        case 'E':
            noteNum = 4 - noteFlat;
            break;
        case 'F':
            noteNum = 5 + noteSharp;
            break;
        case 'G':
            noteNum = 7 + noteSharp - noteFlat;
            break;
        case 'A':
            noteNum = 9 + noteSharp - noteFlat;
            break;
        case 'B':
            noteNum = 11 - noteFlat;
            break;
        case 'R': // Rest note 'R' or 'REST'
            octave = -1;
            break;
        default:
            break;
    }

    // based on equation at http://www.phy.mtu.edu/~suits/NoteFreqCalcs.html and the Verdi tuning
    // fn = f0*(2^1/12)^n where n = number of half-steps from the reference frequency f0
    freq = float(256*pow(1.05946,(     12.0*(octave-4)        +noteNum)));
    //          C4^  (2^1/12)^    12 half-steps in an octave      ^how many extra half-steps within that octave, 0 for 'C'

    // Serial.printlnf("%-3s o:%-2d f:%-5d d:%d", tempNote.c_str(), octave, int(freq), duration);

    if (octave != -1) tone(D0, int(freq), duration);
    delay(duration);
    if (octave != -1) noTone(D0);
}