My midi keyboard project is failing, i think it has something to do with the code

[haluhalu]

Im turning my old casio ctk 230 49 keys keyboard into a midi one using Arduino pro micro,
im using a multiplexer 16 pins.
i have scanned the matrix of the keyboard using multimeter and have figured this out
it has 15 pins, matrix is 7*8 (7 rows and 8 columns)

Row\Col	8	9	10	11	12	13	14	15
1	C2	C#2	D2	D#2	E2	F2	F#2	G2
2	G#2	A2	A#2	B2	C3	C#3	D3	D#3
3	E3	F3	F#3	G3	G#3	A3	A#3	B3
4	C4	C#4	D4	D#4	E4	F4	F#4	G4
5	G#4	A4	A#4	B4	C5	C#5	D5	D#5
6	E5	F5	F#5	G5	G#5	A5	A#5	B5
7	C6	—	—	—	—	—	—	—

now i have connected the rows to the Arduino board, where 1-7 pins are connected to the Arduino 2-9 pins.
the columns from 8-15 are connected to the mux from c15-18(pin 8 connecting on c15 and pin 15 on c8)
initially it was working but some keys weren't working and the were playing off keys i think it has something to do with the code.
please help with the code.

#include midi.h
// Pin Definitions
// Rows are connected to Arduino pins 2–8
const int row1 = 2;
const int row2 = 3;
const int row3 = 4;
const int row4 = 5;
const int row5 = 6;
const int row6 = 7;
const int row7 = 8;

// MUX control pins
const int SIG = A1;
const int S0 = 15;
const int S1 = 14;
const int S2 = 16;
const int S3 = 10;

// mux channel order C15 → C8
int muxChannels[8] = {15,14,13,12,11,10,9,8};

uint8_t keyToMidiMap[56];
boolean keyPressed[56];

int noteVelocity = 127;


// select mux channel (REPLACES shift register scanColumn)
void scanColumn(int columnIndex)
{
    int ch = muxChannels[columnIndex];

    digitalWrite(S0, ch & 1);
    digitalWrite(S1, (ch >> 1) & 1);
    digitalWrite(S2, (ch >> 2) & 1);
    digitalWrite(S3, (ch >> 3) & 1);

    pinMode(SIG, OUTPUT);
    digitalWrite(SIG, LOW);

    delayMicroseconds(30);
}


void setup()
{
    // MIDI mapping from your chart EXACTLY

    // Row 1
    keyToMidiMap[0] = 36;
    keyToMidiMap[1] = 37;
    keyToMidiMap[2] = 38;
    keyToMidiMap[3] = 39;
    keyToMidiMap[4] = 40;
    keyToMidiMap[5] = 41;
    keyToMidiMap[6] = 42;
    keyToMidiMap[7] = 43;

    // Row 2
    keyToMidiMap[8] = 44;
    keyToMidiMap[9] = 45;
    keyToMidiMap[10] = 46;
    keyToMidiMap[11] = 47;
    keyToMidiMap[12] = 48;
    keyToMidiMap[13] = 49;
    keyToMidiMap[14] = 50;
    keyToMidiMap[15] = 51;

    // Row 3
    keyToMidiMap[16] = 52;
    keyToMidiMap[17] = 53;
    keyToMidiMap[18] = 54;
    keyToMidiMap[19] = 55;
    keyToMidiMap[20] = 56;
    keyToMidiMap[21] = 57;
    keyToMidiMap[22] = 58;
    keyToMidiMap[23] = 59;

    // Row 4
    keyToMidiMap[24] = 60;
    keyToMidiMap[25] = 61;
    keyToMidiMap[26] = 62;
    keyToMidiMap[27] = 63;
    keyToMidiMap[28] = 64;
    keyToMidiMap[29] = 65;
    keyToMidiMap[30] = 66;
    keyToMidiMap[31] = 67;

    // Row 5
    keyToMidiMap[32] = 68;
    keyToMidiMap[33] = 69;
    keyToMidiMap[34] = 70;
    keyToMidiMap[35] = 71;
    keyToMidiMap[36] = 72;
    keyToMidiMap[37] = 73;
    keyToMidiMap[38] = 74;
    keyToMidiMap[39] = 75;

    // Row 6
    keyToMidiMap[40] = 76;
    keyToMidiMap[41] = 77;
    keyToMidiMap[42] = 78;
    keyToMidiMap[43] = 79;
    keyToMidiMap[44] = 80;
    keyToMidiMap[45] = 81;
    keyToMidiMap[46] = 82;
    keyToMidiMap[47] = 83;

    // Row 7
    keyToMidiMap[48] = 84;

    pinMode(SIG, INPUT_PULLUP);

    pinMode(S0, OUTPUT);
    pinMode(S1, OUTPUT);
    pinMode(S2, OUTPUT);
    pinMode(S3, OUTPUT);

    pinMode(row1, INPUT_PULLUP);
    pinMode(row2, INPUT_PULLUP);
    pinMode(row3, INPUT_PULLUP);
    pinMode(row4, INPUT_PULLUP);
    pinMode(row5, INPUT_PULLUP);
    pinMode(row6, INPUT_PULLUP);
    pinMode(row7, INPUT_PULLUP);

    Serial.begin(31250);

    delay(1000);
}


void loop()
{
    for (int col = 0; col < 8; col++)
    {
        scanColumn(col);

        int groupValue1 = !digitalRead(row1);
        int groupValue2 = !digitalRead(row2);
        int groupValue3 = !digitalRead(row3);
        int groupValue4 = !digitalRead(row4);
        int groupValue5 = !digitalRead(row5);
        int groupValue6 = !digitalRead(row6);
        int groupValue7 = !digitalRead(row7);


        if (groupValue1 && !keyPressed[col]) {
            keyPressed[col] = true;
            noteOn(0x90, keyToMidiMap[col], noteVelocity);
        }

        if (groupValue2 && !keyPressed[col + 8]) {
            keyPressed[col + 8] = true;
            noteOn(0x90, keyToMidiMap[col + 8], noteVelocity);
        }

        if (groupValue3 && !keyPressed[col + 16]) {
            keyPressed[col + 16] = true;
            noteOn(0x90, keyToMidiMap[col + 16], noteVelocity);
        }

        if (groupValue4 && !keyPressed[col + 24]) {
            keyPressed[col + 24] = true;
            noteOn(0x90, keyToMidiMap[col + 24], noteVelocity);
        }

        if (groupValue5 && !keyPressed[col + 32]) {
            keyPressed[col + 32] = true;
            noteOn(0x90, keyToMidiMap[col + 32], noteVelocity);
        }

        if (groupValue6 && !keyPressed[col + 40]) {
            keyPressed[col + 40] = true;
            noteOn(0x90, keyToMidiMap[col + 40], noteVelocity);
        }

        if (groupValue7 && !keyPressed[col + 48]) {
            keyPressed[col + 48] = true;
            noteOn(0x90, keyToMidiMap[col + 48], noteVelocity);
        }


        // release
        for (int r = 0; r < 56; r++)
        {
            if (!groupValue1 && keyPressed[col]) {
                keyPressed[col] = false;
                noteOn(0x90, keyToMidiMap[col], 0);
            }
        }

        pinMode(SIG, INPUT_PULLUP);
    }
}


void noteOn(int cmd, int pitch, int velocity)
{
    Serial.write(cmd);
    Serial.write(pitch);
    Serial.write(velocity);
}

[UKHeliBob]

This look like a follow on from your other topic. If so then I will consider merging them so that it can be seen in context

I need help with my arduino midi project

I’m trying to convert an old 49-key keyboard into a USB MIDI controller using an Arduino Pro Micro. HERE ARE THE SHEMETAIC OF THE KEYS, A PICTURE OF THE SCAN MATRIK I FOUND USING MULTIMETER AND LASTLY THE DIAGRAM OF THE CIRCUIT (ASSUME THE NANO IS PRO MICRO) The keyboard uses a 15-pin ribbon cable, and after reverse engineering it with a multimeter, I confirmed it is a standard matrix: 7 row lines 8 column lines (one partially unused) 49 keys total Each key connects one row to one column thr…

[J-M-L]

You said

@haluhalu

where 1-7 pins are connected to the Arduino 2-9 pins.

and the code says

@haluhalu

// Rows are connected to Arduino pins 2–8
const int row1 = 2;
const int row2 = 3;
const int row3 = 4;
const int row4 = 5;
const int row5 = 6;
const int row6 = 7;
const int row7 = 8;

seems weird. which it is ? 2-8 or 2-9 without 8 ?

8 and 9 are also in this array...

@haluhalu

// mux channel order C15 → C8
int muxChannels[8] = {15,14,13,12,11,10,9,8};

---

also what's going on with 56 here only for groupValue1 on the release - I have not look deeply at the code but it seems you are doing way more stuff with groupValue1...groupValue7 for the press...

@haluhalu

        for (int r = 0; r < 56; r++)
        {
            if (!groupValue1 && keyPressed[col]) {
                keyPressed[col] = false;
                noteOn(0x90, keyToMidiMap[col], 0);
            }
        }

[robtillaart]

@haluhalu

keyToMidiMap[0] = 36;

A small optimization

for (int i = 0; i < 49; i++) 
{
  keyToMidiMap[i] = i + 36;
}

using array's can help to reduce complexity.

you might have a look at GitHub - RobTillaart/I2CKeyPad8x8: Arduino library for 8x8 or smaller KeyPad connected to an I2C PCF8575.
might be useful for keypad scanning.

[gilshultz]

It looks like lots of problems from the description. Please post an annotated schematic showing exactly how you have wired this project along with links to the technical information on the hardware devices.