// The library for I2C communication
#include "Wire.h"
// Slave address
#define I2C_DEV_ADDR 0x55
// Buzzer PIN
#define BUZZER_PIN 5
// NOTES FOR THE IMPERIAL MARCH
#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
#define REST 0
// How the song goes
int melody[] = {
NOTE_A4,-4, NOTE_A4,-4, NOTE_A4,16, NOTE_A4,16, NOTE_A4,16, NOTE_A4,16, NOTE_F4,8, REST,8,
NOTE_A4,-4, NOTE_A4,-4, NOTE_A4,16, NOTE_A4,16, NOTE_A4,16, NOTE_A4,16, NOTE_F4,8, REST,8,
NOTE_A4,4, NOTE_A4,4, NOTE_A4,4, NOTE_F4,-8, NOTE_C5,16,
NOTE_A4,4, NOTE_F4,-8, NOTE_C5,16, NOTE_A4,2,
NOTE_E5,4, NOTE_E5,4, NOTE_E5,4, NOTE_F5,-8, NOTE_C5,16,
NOTE_A4,4, NOTE_F4,-8, NOTE_C5,16, NOTE_A4,2,
NOTE_A5,4, NOTE_A4,-8, NOTE_A4,16, NOTE_A5,4, NOTE_GS5,-8, NOTE_G5,16,
NOTE_DS5,16, NOTE_D5,16, NOTE_DS5,8, REST,8, NOTE_A4,8, NOTE_DS5,4, NOTE_D5,-8, NOTE_CS5,16,
NOTE_C5,16, NOTE_B4,16, NOTE_C5,16, REST,8, NOTE_F4,8, NOTE_GS4,4, NOTE_F4,-8, NOTE_A4,-16,
NOTE_C5,4, NOTE_A4,-8, NOTE_C5,16, NOTE_E5,2,
NOTE_A5,4, NOTE_A4,-8, NOTE_A4,16, NOTE_A5,4, NOTE_GS5,-8, NOTE_G5,16,
NOTE_DS5,16, NOTE_D5,16, NOTE_DS5,8, REST,8, NOTE_A4,8, NOTE_DS5,4, NOTE_D5,-8, NOTE_CS5,16,
NOTE_C5,16, NOTE_B4,16, NOTE_C5,16, REST,8, NOTE_F4,8, NOTE_GS4,4, NOTE_F4,-8, NOTE_A4,-16,
NOTE_A4,4, NOTE_F4,-8, NOTE_C5,16, NOTE_A4,2,
};
// It divides the value of the array and the first item of the array
// and it is divided by 2, because it stores the value of the note and the duration.
// So the total notes of the melody is half of the elements in the array.
int notes = sizeof(melody) / sizeof(melody[0]) / 2;
// How fast is the song goes
int tempo = 120;
// It calculates the duration of one whole note in milliseconds.
int wholenote = (60000 * 4) / tempo;
// divider: It is used to obtain the duration of each note of the melody.
// noteDuration: It stores the duration in milliseconds of each individual note,
// after the calculus.
int divider = 0, noteDuration = 0;
// Variable to control the state of the song.
volatile bool playSong = false;
void onReceive(int len) {
// It waits till something is available
while (Wire.available()) {
// It stores the 1 in a char variable
char c = Wire.read();
if (c == '1') {
// It changes the state of the song
// so it can start or stop
playSong = !playSong;
// Serial prints to check if the song is playing
Serial.print("playSong: ");
Serial.println(playSong ? "ON" : "OFF");
}
}
}
void setup() {
// It initializes the serial port
Serial.begin(115200);
// It initializes the I2C communication
Wire.begin(I2C_DEV_ADDR);
Wire.onReceive(onReceive);
// It initializes the buzzer as output
pinMode(BUZZER_PIN, OUTPUT);
}
void loop() {
// It plays the song playSong is true
if (playSong) {
// A for loop to play the song
for (int thisNote = 0; thisNote < notes * 2; thisNote = thisNote + 2) {
// If playSong is false it stops playing
if (!playSong) break;
// It obtains the duration of the actual
// note in the melody
divider = melody[thisNote + 1];
// It checks if divider es greater than 0,
// which says that it is a normal note.
if (divider > 0) {
noteDuration = (wholenote) / divider;
// It checks if divider is less than 0,
// which says that it is a dotted note.
} else if (divider < 0) {
// It calculates the duration of the dotted note.
noteDuration = (wholenote) / abs(divider);
// It in increases the duration of the dotted note.
noteDuration *= 1.5;
}
// It generates a tone for the buzzer with the
// frequency of the actual note.
tone(BUZZER_PIN, melody[thisNote], noteDuration * 0.9);
// It waits the whole note duration before the next one.
delay(noteDuration);
// It stops the generation of the tone.
noTone(BUZZER_PIN);
}
} else {
// Small delay so it waits for the next instruction.
delay(100);
}
}