Electronic Instrument

This electronic instrument allows you to sequence and loop audio and MIDI data.  Most of the time I use it to sequence drum samples so I can play around with different beats and rhythms.  The really great thing about this instrument is that it is very portable, it fits in your hands easily, runs off a single 9 volt battery, and has a headphone jack that you can plug into.  If you connect it to your computer via usb you can also use it to send MIDI data, this way you can communicate with other electronic instruments or software environments that understand MIDI. 

Parts List:

(x1) Arduino Uno (Duemilanove is fine, but make sure it is ATMEL328P) Radioshack #276-128
(x1) Arduino ProtoShield Radioshack #276-140
(x1) PC Board with Copper Radioshack #276-147
(x9) High Tact Switch Radioshack #275-002  (I really liked the feel of these buttons, but they only come in a surface mount version, which makes them fairly difficult to solder because of the small leads.  Additionally, since these buttons are square it is harder to drill a hole for them in an enclosure.  If you are a beginner, you might want to use a different type of button, any of these momentary switches will work)
(x1) 10KOhm Audio Control Potentiometer with SPST Switch Radioshack #271-215 (this will be used to control volume and turn the device on/off)
(x1) 50K-Ohm Linear-Taper Potentiometer Radioshack #271-1716
(x2) 220µF 35V 20% Radial-lead Electrolytic Capacitor (or anything between 200 and 300 uF) Radioshack #272-1029
(x2) SPST PC-Mountable Submini Toggle Switch Radioshack #275-645
(x2) Silver Tone Knurled Knob (or any knob with 0.25" inner diameter) Radioshack #274-424
(x9) 1N914/4148-Type Diode (two packages) Radioshack #276-1122
(x3) 2K ohm 1/2W 5% Carbon Film Resistor (1 package)
(x10) 10K Ohm 1/4-Watt Carbon Film Resistor (2 packages) Radioshack #271-1335
(x8) 20K Ohm 1/4-Watt Carbon Film Resistor (2 packages)
(x1) 4.7K Ohm 1/4-Watt Carbon Film Resistor Radioshack #271-1330
(x1) 1K Ohm 1/4-Watt Carbon Film Resistor Radioshack #271-1321
(x1) 5K Ohm 1/4-Watt Carbon Film Resistor
(x1) 9V Alkaline Battery Radioshack #23-853
(x1) Heavy-Duty 9V Snap Connectors Radioshack #270-324
(x1) Amber Super-bright LED Indicator Radioshack #55050630
(x1) White Super-bright LED Indicator Radioshack #55050633
(x1) 1/8" Stereo In-Line Audio Jack Radioshack #274-274
(x1) LM386 Low Voltage Audio Power Amplifier (8-Pin DIP) Radioshack 276-1731
(1x) 8 Pin Socket 276-1995 Radioshack 276-1995

Additional materials:

22 Gauge Wire Radioshack #278-1224
Solder Radioshack #64-013
drill
plywood
polyurethane finish
sand paper
hot glue
super glue
four wood screws
Heat Shrink Wrap Radioshack #278-1610
Electrical Tape Radioshack #64-2375

I've included fritzing breadboard diagrams (divided into a few parts) and schematics for this project as well as all firmware.  You can find these documents throughout the body of this instructable or download them all in one zip file below.

Step 1: Build enclosure

I used AutoCAD, Autodesk 123D Make, and CorelDRAW to design my project enclosure.  I've attached the AutoCAD, STL, and the EPS files for the enclosure I built below.  Then I sent my EPS files to a laser cutter and cut them out of 0.2" plywood.  I also cut a front panel out of 3mm acrylic.  If you do not have access to a laser cutter, you can buy a project enclosure or find a spare box and drill holes in it for all your components, be creative!

I wanted to sand off the scorched ends of the laser cut pieces so that the outside of the box had a consistent finish, so I also made a set of eps files with some extra length on the ends for sanding ("enclosure long").

I glued the pieces together with wood glue and cut a piece of acrylic for the front panel.

Comments

[markgoebel]

Thank you Amanda. I downloaded the newMIDIRoute.zip and I do see the print button. It shows all my MIDI ports. I don't have my project with me at the moment, but will update you when I get to it. Thanks again for your help.

[amandaghassaei]

cool, glad to hear it.

[markgoebel]

Ok, got home, hooked up my Arduino, loaded the MIDI firmware, closed Arduino, unhooked my USB, loaded Max/MSP, opened NewMIDIRoute.maxpat
plugged in USB, enabled metronome, looked at the print screen. "Read 0", tried changing MIDI ports. Same result. Then I reset Max and checked my MIDI ports listed and is says,

port a: Bluetooth-PDA-Sync
port b: Bluetooth-Modem
port c: MyiPhone....

This doesn't make sense to me. Not sure if this is correct. Doesn't seem like it should be. It seems to me like it should list a USB port connection...or a Bus 1 port, but since I'm new to this I don't know.

[amandaghassaei]

what do the .... mean, were those the only ports listed?

[markgoebel]

Oh hahaha. The .... was me paraphrasing the name it gave for my iPhone. Yes, these are the only ports listed when I hit the print button.

[amandaghassaei]

Do you have the arduino plugged into the comp?

[markgoebel]

Hi Amanda,

Thanks for attempting to help me again. I'm not having any luck. One difference I have noticed is that my Arduino files end in .INO yours end in .PDE I am not sure if this has any relevance. It's something I noticed when I had to make changes to your code and save it. Another thing I'm not clear on is if I am initializing the Max patch correctly. I open it, plug in my USB, click on the X and go to the bottom and double click Noteout and choose either MaxRunTime 1 or 2. I've tried all the MIDI channels separately as well and I still get nothing. Your tip on printing CMD + Control + M is not working either. I get an error sound. I also don't see a Print button. I won't give up cuz I have my heart set on making this work, but it is pretty frustrating. Thanks for your patience.

Just to be clear...

I'm using Mac OS 10.8.3
Arduino R3 with ATMEGA 328P
USB Cable (Obvious, but I'm so frustrated I included it to be funny.)
2 breadboards...haven't built the pots and switches yet.
And all the parts you listed.

WHERE AM I GOING WRONG???

[amandaghassaei]

upload the firmware, close arduino, unplug arduino from comp, plug the arduino into your comp, open max
it's not command+control+M it's command or control + m (depends if you are using windows or mac)
the print button is grey and oval shaped, it says "print" it is near the top of the max patch
don;t worry about noteout for now, you should see the squares in the grid light up when you press the buttons.
let me know how it goes, send me the output from that print thing.

[markgoebel]

I just bought Max/MSP last night. I just came across this reply from you. I do not have an oval shaped print button in the Max patch, but now I can add one. Where should I add it? Again...thank you. Sorry for the constant troubleshooting. I can't wait till I have a finished product. I will certainly appreciate the process once it's done.

[amandaghassaei]

did you redownload the midirouter? it's called newMIDIrouter.zip, there is a grey print button

[markgoebel]

Can you guide me to it? I am scouring my mac to see if I downloaded it and I have not. I was going through the website and the PDF and I cannot find it. Thanks!

[amandaghassaei]

Step 20

[markgoebel]

Hi Amanda,

I just wanted to update you on where I'm at with this project. I've ordered the hi tact switches from geeetech.com. I was able to get 50 of them for $2.50. They have longer leads than the Radio Shack switches so i will be able to stick them in the breadboard. I'm hoping they arrive in the next couple of days. I was wondering if you were able to upload the code I amended and if it works with your Glitchbox? Thanks for your advice.

[markgoebel]

I did as you instructed. The Max window shows nothing. It's blank. It has two columns one for Object and one for Message. I do not have a Print button on the Max patch file I am opening...MIDIroute. One more thing I am noticing. When I press buttons no lights on the Arduino blink. Tx and Rx don't even light up.

[amandaghassaei]

are you sure you have the 4 lead tact switches wired up correctly?

[markgoebel]

So, I took everything apart and put it all back together again to notice that the switches I bought were too big and it was causing me to lose a column on each side of the breadboard. I'm thinking this could be where my problem lies. I went to Radio Shack and purchased the ones you have on your list and they are too small to fit on the breadboard. I will have to solder wire to them and test it that way and will let you know. Do you have a suggestion as to how long the wires should be for the buttons? If this doesn't work I'm going to check myself into a mental institution. Thanks for your help Amanda.

[amandaghassaei]

haha, well I hope it doesn't come to that! make the wires about ten inches long, you can always cut them down later.

[markgoebel]

I wired up the switches and made sure everything else was wired up on the breadboard according to the Fritzing sketch. Did you have a problem uploading the code I amended? I wonder if it could be that...

[amandaghassaei]

now you can't get the code to upload?

[markgoebel]

Yes I can upload the amended code fine. I thought I remembered a comment you made that my code looked fine but when you tried to upload it it didn't work. So I was following up on a reply you made awhile back...or am I mistaken? Happy Monday btw :-)

[markgoebel]

//glitchbox
//by Amanda Ghassaei 2012

////todo
//led data
//audio storage
//send out audio
//trigger audio
//pot control
//switches
//timers
//turn off midi-send clear when mute

/***********************************************************************
if you want to add your own audio samples, compress them to 8 bit 8kHz using these instructions:
and paste the data into the memory below. the buttons are arranged as follows:

0 1 2

3 4 5

6 7 8

***********************************************************************/

//AUDIO STORAGE
boolean on1 = 0;
boolean on2 = 0;
boolean on3 = 0;
boolean on4 = 0;
boolean on5 = 0;
boolean on6 = 0;
boolean on7 = 0;
boolean on8 = 0;
boolean on9 = 0;


//variables for loops
byte i;
byte j;
byte k;

//position variables
byte x;
byte y;
//states
byte state = 0;

//position variables
byte xseq;
byte yseq;
//states
byte stateseq = 0;

//data storage for buttons
boolean button_current[9];//current state
boolean button_last[9];//last state
boolean button_state[9];//current debounced state
byte button_debounce_count[9];//debounce counter
boolean button_event[9];//event signal
byte buttonData;//used for reading portc
int kButtonUpDefaultDebounceCount = 12; // Used in button debouncing


/***********************************************************************
change the number following "#define steps" to set the number of steps in your sequencer.
default is 16
***********************************************************************/
//sequencer
#define steps 16
byte sequencer[steps][9];//32 step sequencer storage

//REC- turn sequencer on/off
boolean currentrec = 0;
boolean prevrec = 0;
boolean recdebounce = 0;
byte recdebouncecount;//debounce rec switch
//variables for loops
byte recdebouncesteps;
byte recdebouncei;


int seqTimer = 0;

boolean seqONcurrent = 1;//optional mute recorded sequences
boolean seqONprev = 1;
boolean seqON = 1;
byte seqONcounter;//debounce mute switch
boolean initonoff;

//BPM
int BPMvalcurrent;
int BPMvalstored;


void buttonInit() {
byte i;
for (i = 0; i <9; i++) {
button_current[i] = 0;
button_last[i] = 0;
button_state[i] = 0;
button_event[i] = 0;
}
PORTB = 0xFF;//set all pins high
}


//MUCH OF THIS BUTTON DEBOUNCING FUNCTION WAS COPIED FROM THE MONOME 40H FIRMWARE BY JOE LAKE AND BRIAN CRABTREE
// buttonCheck - checks the state of a given button.
void buttonCheck(byte index)
{
if ((button_current[index] ^ button_last[index]) && // if the current physical button state is different from the
(button_current[index] ^ button_state[index])) { // last physical button state AND the current debounced state

if (button_current[index]) { // if the current physical button state is depressed
button_event[index] = 1; // queue up a new button event immediately
button_state[index] = 1; // and set the debounced state to down.
}
else{
button_debounce_count[index] = kButtonUpDefaultDebounceCount;
} // otherwise the button was previously depressed and now
// has been released so we set our debounce counter.
}
else if ((button_current[index] ^ button_last[index]) == 0 && // if the current physical button state is the same as
(button_current[index] ^ button_state[index])) { // the last physical button state but the current physical
// button state is different from the current debounce
// state...

if (button_debounce_count[index] > 0 && --button_debounce_count[index] == 0) { // if the the debounce counter has
// been decremented to 0 (meaning the
// the button has been up for
// kButtonUpDefaultDebounceCount
// iterations///

button_event[index] = 1; // queue up a button state change event

if (button_current[index]){ // and toggle the buttons debounce state.
button_state[index] = 1;
}
else{
button_state[index] = 0;
}
}
}
}

void buttonpress() {

// digitalWrite(8,HIGH);
// digitalWrite(9,HIGH);
// digitalWrite(10,HIGH);
PORTB |= 0x07;//set pins 8, 9, 10 high


for (i=0; i<9; i++) {
button_last[i] = button_current[i];
}

//THE FOLLOWING CODE CHECKS THE STATES OF THE BUTTONS
digitalWrite(8,LOW);

button_current[2] = 1^digitalRead(A0);
button_current[1] = 1^digitalRead(A1);
button_current[0] = 1^digitalRead(A2);

digitalWrite(8,HIGH);
digitalWrite(9,LOW);

button_current[5] = 1^digitalRead(A0);
button_current[4] = 1^digitalRead(A1);
button_current[3] = 1^digitalRead(A2);

digitalWrite(9,HIGH);
digitalWrite(10,LOW);

button_current[8] = 1^digitalRead(A0);
button_current[7] = 1^digitalRead(A1);
button_current[6] = 1^digitalRead(A2);

digitalWrite(10, HIGH);

////SAME AS THE CODE ABOVE- WITHOUT ARDUINO LIBRARY COMMANDS
//for (j=0; j<3; j++){
// PORTB &= ~(1<//
//// buttonData = PORTC & 0x07;//read pins a0,a1,a2
//// for (k=0; k<3; k++){
//// button_current[3*j+k] = ((~buttonData & (1 << k)) >> k);//load data into button_current
//// }
//
// button_current[3] = 1^digitalRead(A0);
// button_current[4] = 1^digitalRead(A1);
// button_current[5] = 1^digitalRead(A2);
// PORTB |= (1<//}
for (i=0; i<9; i++) {
buttonCheck(i);
if (button_event[i]) {//if there has been a button event send serial data/data to sequencer
button_event[i] = 0;
x = i % 3;//x coordinate
y = i / 3;//y coordinate
state = button_state[i];//on/off
Serial.write(((x << 6) | (y << 4)) | (state<<3));
if (recdebounce){//if in rec mode
sequencer[seqTimer/2+seqTimer%2][i] = state+1;//store a 1 in sequencer for release and 2 for start, and quantize to nearest beat
}
}
}
}

void bpmRead(){
}

void checkSwitches(){

prevrec=currentrec;
if (digitalRead(A3)){
currentrec = 0;//
}
else{
currentrec = 1;
}
if ((currentrec ^ prevrec) && (currentrec ^ recdebounce)){//current diff than prev and debounce
if(currentrec){//currently 1
recdebounce=1;//debounce now set to 1
for (recdebouncesteps=0; recdebouncesteps for (recdebouncei=0; recdebouncei<9; recdebouncei++){
sequencer[recdebouncesteps][recdebouncei] = 0;//clear out sequencer for new pattern
Serial.write(1);//clear surrent midi
initonoff=digitalRead(A4);//set mute off
}
}
}
else {
recdebouncecount=12;//else set debounce counter to 12
}
}
else if ((currentrec == prevrec) && (currentrec ^ recdebounce)) {//if current prev and diff than debounce
if (recdebouncecount > 0 && --recdebouncecount == 0) {//decrease debounce counter and check to see if = 0
if (currentrec){//if debounce counter = 0 toggle debounced state
recdebounce = 1;
for (recdebouncesteps=0; recdebouncesteps for (recdebouncei=0; recdebouncei<9; recdebouncei++){
sequencer[recdebouncesteps][recdebouncei] = 0;//clear out sequencer for new pattern
Serial.write(1);//clear current midi
initonoff=digitalRead(A4);//set mute off
}
}
}
else{
recdebounce = 0;
}
}
}


seqONprev=seqONcurrent;
if (digitalRead(A4)){
seqONcurrent = 1;//
}
else{
seqONcurrent = 0;
}
if ((seqONcurrent ^ seqONprev) && (seqONcurrent ^ seqON)){//current diff than prev and debounce
if(seqONcurrent){//currently 1
seqON=1;//debounce now set to 1
Serial.write(1);//end current MIDI
}
else {
seqONcounter=12;//else set debounce counter to 12
}
}
else if ((seqONcurrent == seqONprev) && (seqONcurrent ^ seqON)) {//if current prev and diff than debounce
if (seqONcounter > 0 && --seqONcounter == 0) {//decrease debounce counter and check to see if = 0
Serial.write(1);//end current MIDI
if (seqONcurrent){//if debounce counter = 0 toggle debounced state
seqON = 1;
}
else{
seqON = 0;
}
}
}
}

void checkBPM(){
BPMvalcurrent=analogRead(A5);
if (abs(BPMvalcurrent-BPMvalstored)>8){//if change exceeds noise tolerance
BPMvalstored = BPMvalcurrent;
OCR1A = 31250/(BPMvalstored/100); // compare match register 16MHz/256/2Hz
}
}


ISR(TIMER1_COMPA_vect){
if (seqTimer==2*steps-1){
seqTimer=0;
}
else{
seqTimer+=1;//increase seqTimer by 1
}
if (seqON==initonoff){//if mute is off
if (seqTimer%2==0){//every other tick
PORTB&=B11100111;//turn off LEDs
//Serial.write(1,);//clear out midi from last time step
for (byte iseq=0; iseq<9; iseq++) {
stateseq = sequencer[seqTimer/2][iseq];
xseq = iseq % 3;//x coordinate
yseq = iseq / 3;//y coordinate
if ((stateseq==1)|(stateseq==2)){
Serial.write(((xseq << 6) | (yseq << 4)));//byte [xxyy(off)---]//clear out midi
Serial.write(((xseq << 6) | (yseq << 4)) | ((stateseq-1) << 3));//byte [xxyy(on/off)---]
}
}
if (seqTimer%(steps/2) ==0) {//turn led on every forth tick
if (recdebounce){
PORTB|=B00001000;//turn on amber LED
}
else{
PORTB|=B00010000;//turn on white LED
}
}
}
}
else{
if (seqTimer%2==0){//every other tick
PORTB&=B11100111;//turn off LEDs
}
if (seqTimer%(steps/2) ==0) {//turn led on every forth tick
if (recdebounce){
PORTB|=B00001000;//turn on amber LED
}
else{
PORTB|=B00010000;//turn on white LED
}
}
}
}

void setup() {

//button data out on pins 8, 9, 10
DDRB = 0xFF;
//button data in on pins A0, A1, A2
DDRC = 0x00;

BPMvalstored = analogRead(A5);

// //SETUP TIMER2 FOR SEQUENCER
cli();//stop interrupts
// TCNT2=0x00;
// OCR2A = 250; // 1 ms @ Fosc = 16 MHz
// TCCR2A=0x02; // WGM: No wave generation
// TCCR2B=0x04; // START Timer, prescaler = 64
// TIMSK2 = (1 << TOIE2); // Enable interrupt when Timer reaches OCRA

// set up Timer 2
// Timer 2 - gives us our 1 mS counting interval
// 16 MHz clock (62.5 nS per tick) - prescaled by 128
// counter increments every 8 uS.
// So we count 125 of them, giving exactly 1000 uS (1 mS)
// TCCR2A = 0; // stop timer 2
// TCCR2B = 0;
// TCNT2 = 0; // reset counter
//
// OCR2A = 124; // count up to 125 (zero relative!!!!)
// TCCR2A = _BV (WGM21) ; // CTC mode
// TCCR2B = _BV (CS20) | _BV (CS22) ; // start Timer with a prescaler of 128
// TIMSK2 = _BV (OCIE2A); // enable Timer2 Interrupt (ie. every 1 mS)
//
// TCCR2A = 0;
// TCCR2B = 0;
// TCNT2 = 0;
//
// OCR2A = 255; // compare match register 16MHz/256/2Hz
// TCCR2B |= (1 << WGM21); // CTC mode
// TCCR2B |= (1 << CS20); // 256 prescaler
// TIMSK2 |= (1 << OCIE2A); // enable timer compare interrupt

TCCR1A = 0;
TCCR1B = 0;
TCNT1 = 0;



OCR1A = 31250/(BPMvalstored/100); // compare match register 16MHz/256/2Hz
TCCR1B |= (1 << WGM12); // CTC mode
TCCR1B |= (1 << CS12); // 256 prescaler
TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt

sei();//allow interrupts

//initialize mute switch so that it allows playback on startup
initonoff=digitalRead(A4);

PORTB = 0x07;//set pins 8, 9, 10 high, 11, 12 low

Serial.begin(57600);//not initializing properly when unplugged and replugged

buttonInit();

Serial.write(1);//clear message

}

void loop() {
buttonpress();
checkBPM();
checkSwitches();
checkBPM();
}

[amandaghassaei]

this looks fine, try using the attached max patch. if it still does not work hit the print button in the maxmsp patch and copy what comes out from the max window (command/control + M).

[amandaghassaei]

couldn't upload the file, try the new patch that I uploaded in step 20

[markgoebel]

Hi Amanda,

Happy Monday! Sorry to bother you again. I am still having trouble testing the button schematic. I amended the code and got it to upload ok, but nothing is happening when I press the buttons. Can I send you my code to make sure I amended it ok?

[amandaghassaei]

sure paste in in a reply

[markgoebel]

I realized I didn't upload the MIDI firmware to the Arduino...when I found it and tried to verify it I get an error that says, "The "BYTE" keyword is no longer supported. Please use Serial.write() instead.

How do I amend this in your code?

[amandaghassaei]

just use serial.write and remove the BYTE part and the preceding comma.

[markgoebel]

I tried your suggestion. Nothing has worked. I went ahead and built the rest the project based on your Fritzing sketches and cannot get anything to work. The battery isn't even getting warm. I included a photo and I know you probably can't see what the problem is from the photo I just wanted you to see that I'm attempting this.

On the Arduino end of things, I uploaded your sketch and clicked on the Monitor. I get gibberish. I even made sure the baud was set to 57600. Feeling not sooo smart. Hahaha. Please help. Thanks.

[amandaghassaei]

upload the firmware, close arduino, plug the arduino into your comp, open max

[markgoebel]

No luck in any of the combinations I'm trying. Just to be clear I'm trying to test the 4 lead button Fritzing sketch only. The rest of the circuit I haven't yet built all the way. Speaking of which, I bought all the parts on this list, but I noticed on the Circuit sketch that there are 2 ceramic capacitors that are not on the list. Must they be Ceramic or can I get film? Not sure which is better since I am new at this. I'm also trying to get something today instead of having to wait for Radio Shack to mail it to me. Thanks again for any help you give me.

[markgoebel]

Hi Amanda,

I am trying to prototype your project. I would like to test the buttons from the Fritzing sketch. You suggested I run MaxRunTime. I downloaded it, got the MIDI firmware up, plugged in my Arduino attached to my breadboard. I clicked the X to start the metronome and right clicked on noteout to set the MIDI out...I attempted both from MaxRunTime 1 and 2. No luck. Is there a step I am missing? Thanks for your help.

[amandaghassaei]

Try changing the order that you plug in the arduino and turn on max.

[Nortant]

The programmer says binary sketch size 31620 bytes (of a max of 30720)- 102 percent used

[Nortant]

Thanks for your previous replying. I can not fully understand what each part of the program does. Do you have time to step through and explain each block. I also could not find the sound samples, maybe it is the lines containing' Boolean .......?'

[amandaghassaei]

the samples are the long arrays of numbers at the top of the sketch. delete one or two of them and replace the big array with {127};

[Nortant]

Thanks again, it sounds wierd but those sound sample numbers didn't appear in the firmware I first downloaded. But now I have them thank you.
Have you been able to use a mini sd card for storage of longer samples?

[Nortant]

Thanks again, it sounds wierd but those sound sample numbers didn't appear in the firmware I first downloaded. But now I have them thank you.
Have you been able to use a mini sd card for storage of longer samples?

[amandaghassaei]

you could, but then you have to deal with reading from the sd card.

[amandaghassaei]

try deleting the contents of one of the samples and replacing it with {127};

[Nortant]

I will have to find some code to delete that won,t affect the program too much. has anyone else found this problem?