Demonstration

coming soon


Why can Step Motor Create Music?

When step motor moves with a specific speed value, it creates the vibration with a specific frequency, the vibration make the surrounding environment oscillate. The oscillation creates a mechanical wave. Frequency value is depended on the speed. When frequency value is between about 20 Hz and 20 kHz, it becomes sound wave and our ear can hear it.
By adjusting the speed, we can create the different frequency of sound. Therefore, we can create a different note of music.
By mapping music notes of a song to speed, moving step motor with the speed values in sequence, step motor can create melody of that song. We can use more than one motor to play a complex song.
Different material connected with motor will create the different timbre.




Things Used In This Project


In demonstration video, I use the step motor to play "Marble Machine" song.




Wiring
  • Stack PHPoC Shield or PHPoC WiFi Shield on Arduino
  • Stack Two Stepper Motor Controllers PES-2604 on PHPoC Shield or PHPoC WiFi Shield
  • Connect stepper motors to terminal block of Stepper Motor Controller PES-2605
    • Bipolar stepper motor

    • Unipolar stepper motor: there are two ways to connect a unipolar stepper motor to terminal block of PES-2605. User can choose one of them.

  • Set expansion ID for each step motor controllers are 13 and 14 via DIP switch on expansion board.
    You can refer to below table to set expansion ID.
Click image for larger version

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Source Code


Code:
#include <math.h>
#include <Phpoc.h>
#include <PhpocExpansion.h>


ExpansionStepper step1(13);
ExpansionStepper step2(14);

ExpansionStepper steps[2] = {step1, step2};

void stepPlaySetup(int play_id, int vref = 8, int mode = 2, int accel = 10000);

void setup() {
Serial.begin(9600);
while(!Serial)
;

Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);
Expansion.begin();

stepPlaySetup(0);
stepPlaySetup(1);
stepPlayTempo(38);

play_marble_machine_song();
}

void loop() {

}

const char melody1a[] PROGMEM = "5E2.67 4B2 4A8 4G8 4A4 4B4 4G8 4A8 5D8 R2.67 4B2 4A8 4G8 4A4 4F#4 4G8 4A8 5D8";
const char melody1b[] PROGMEM = "R2.67 4B2 5D8 5C8 4B4 4A4 4G8 4A8 4E8 R8 4C8 4E8 4B8 3B8 4C8 4D8 5D8 5C8 4B4 4A4 4G8 4A8 5E8";
const char melody1c[] PROGMEM = "R2.67 4B2 4A8 4G8 4A4 4B4 4G8 4A8 5D8 R2.67 4B2 5D8 5C8 4B4 4A4 4G8 4A8 5D8";
const char melody1d[] PROGMEM = "R2.67 4B2.67 4A8 5E8 R8 4B4 4A4 4G8 4F#8 4E8 R8 3B8 4C8 4F#8 4C8 4E8 4G8 4D8 4F#8 4A8 3B8 4B8 4D8 4G8 4A8 5E8";

const char chord1a[] PROGMEM = "3E4 4E2.67 3E8 4E4 3E4 4E2.67 3E8 4E4 3G4 4G2.67 3G8 4G4 3G4 4G2.67 3G8 4G4";
const char chord1b[] PROGMEM = "3D4 4D2.67 3D8 4D4 3D4 4D2.67 3D8 4D4 3C4 4C2.67 3C8 4C4 3D4 4D2.67 3D8 4D4";
const char chord1c[] PROGMEM = "3E4 4E2.67 3E8 4E4 3E4 4E2.67 3E8 4E4 3G4 4G2.67 3G8 4G4 3G4 4G2.67 3G8 4G4";
const char chord1d[] PROGMEM = "3D4 4D2.67 3D8 4D4 3D4 4D2.67 3D8 4D8 3C4 4C2.67 3C8 4C4 3D4 4D2.67 3D8 4D4";

const char* const melody_table[] PROGMEM = { melody1a, melody1b, melody1c, melody1d };
const char* const chord_table[] PROGMEM = { chord1a, chord1b, chord1c, chord1d };

char buffer[110];

int melody[4][55];
int chord[4][55];
byte melody_len[4], chord_len[4];

void play_marble_machine_song() {
for (byte i = 0; i < 4; i++) {
strcpy_P(buffer, (char*)pgm_read_word(&(melody_table[i])));
melody_len[i] = stepPlayEncode(buffer, melody[i]);
strcpy_P(buffer, (char*)pgm_read_word(&(chord_table[i])));
chord_len[i] = stepPlayEncode(buffer, chord[i]);
}

for(byte i = 0; i < 4; i++) {
stepPlayChangeDir();
stepPlayHarmony(melody[i], chord[i], melody_len[i], chord_len[i]);
//stepPlayMelody(melody[i], melody_len[i]);
}

Serial.println("End!");
}

/* Library */
int stepPlaySpeed = 1000; // ms per bar
int stepPlayDirection = +1;

void stepPlaySetup(int play_id, int vref = 8, int mode = 2, int accel = 10000) {
steps[play_id].setVrefStop(2);
steps[play_id].setVrefDrive(vref);
steps[play_id].setMode(mode);
steps[play_id].setAccel(accel);
}

void stepPlayTempo(int tempo) {
stepPlaySpeed = (int)(1000.0 / (tempo / 60.0));
}

void stepPlayChangeDir() {
stepPlayDirection *= -1;
}

int stepPlayEncode(char *score, int *score_encoded) {
char note[10];
int score_len = 0;
int score_encoded_id = 0;
int blankPos = -1;
int blankPosNext = 0;

while(blankPosNext != -1) {
float dur_fp;
long dur_ms;
long freq;

blankPosNext = blankPos + 1;

while(score[blankPosNext] != ' ') {
blankPosNext++;
if(score[blankPosNext]  == 0) {
score_len = blankPosNext;
blankPosNext = -1;
break;
}
}

if(blankPosNext >= 0) {
int i;
for(i = blankPos + 1; i < blankPosNext; i++)
note[i - (blankPos + 1)] = score[i];

note[i - (blankPos + 1)] = 0;
blankPos = blankPosNext;

if(note[0] == ' ')
continue;
} else {
int i;
for(i = blankPos + 1; i < score_len; i++)
note[i - (blankPos + 1)] = score[i];

note[i - (blankPos + 1)] = 0;
}

if(note[0] == 'R') { /* rest */
note[0] = '0';
dur_fp =  atof(note);
dur_ms = (long)(stepPlaySpeed / dur_fp);

freq = 0;
} else { /* tone */
int tone = (note[0] - 48)  * 12; // octave * 12

// C  C# D  D# E  F  F# G  G# A A# B
// 0  1  2  3  4  5  6  7  8  9 10 11

switch(note[1]) {
case 'C':
tone += 0;
break;
case 'D':
tone += 2;
break;
case 'E':
tone += 4;
break;
case 'F':
tone += 5;
break;
case 'G':
tone += 7;
break;
case 'A':
tone += 9;
break;
case 'B':
tone += 11;
break;
default:
Serial.print("encode_score: unknown tone: ");
Serial.println(note);
return 0;
}

if(note[2] == '#') {
tone++;
note[0] = '0';
note[1] = '0';
note[2] = '0';
} else if(note[2] == 'b') {
tone--;
note[0] = '0';
note[1] = '0';
note[2] = '0';
} else {
note[0] = '0';
note[1] = '0';
}

dur_fp = atof(note);
dur_ms = (long)(stepPlaySpeed / dur_fp);

int octave = tone / 12;
tone = tone % 12;

long freqA = 440.0 * pow(2, (octave - 4));
freq = (int)(freqA * pow(2, (tone - 9) / 12.0));
}

score_encoded[score_encoded_id++] = freq;
score_encoded[score_encoded_id++] = dur_ms;
}

return score_encoded_id;
}

void stepPlayMelody(int *melody, int melody_len) {
int melody_count = 0;

while(melody_count < melody_len) {
int freq = melody[melody_count++];
int dur_ms = melody[melody_count++];

if(freq) {
steps[0].setSpeed(freq);
steps[0].stepGoto(stepPlayDirection * 1000000);

delay(dur_ms);
steps[0].stop(0);
} else // zero frequency is 'rest'
delay(dur_ms);
}
}

void stepPlayHarmony(int *melody1, int *melody2, int melody1_len, int melody2_len) {
int *melody[2] = {melody1, melody2};
unsigned long melody_start_ms = millis();
unsigned long melody_next_ms[2] = { 0, 0 };
int melody_count[2] = { 0, 0 };
int melody_len[2] = { melody1_len, melody2_len };

while((melody_count[0] < melody_len[0] ) || (melody_count[1] < melody_len[1] ) || melody_next_ms[0] || melody_next_ms[1]) {
for(int i = 0; i < 2; i++) {
if(melody_next_ms[i]) {
if(melody_next_ms[i] <= millis()) {
steps[i].stop(0);
melody_next_ms[i] = 0;
}
} else {
if(melody_count[i] < melody_len[i] ) {
int freq = melody[i][melody_count[i]];
int dur_ms = melody[i][melody_count[i] + 1];

melody_count[i] += 2;

if(freq) {
steps[i].stop(0);
steps[i].setSpeed(freq);
steps[i].stepGoto(stepPlayDirection * 1000000);

Serial.print("freq: ");
Serial.print(freq);
Serial.print(", dur_ms: ");
Serial.println(dur_ms);
}

melody_next_ms[i] = millis() + dur_ms;
}
}
}
}
}