MIDI-Ino - An Arduino custom MIDI controller with Mixxx mappings

midi-ino.ino

#include <USB-MIDI.h>

USBMIDI_CREATE_DEFAULT_INSTANCE();

const float K_MAX = 690;
const float K_THRESHOLD = 1;

const byte K_PINS[5]= { A0, A1, A2, A3, A4 };
const byte L_PINS[5]= { 2, 3, 4, 5, 6 };
const byte B_PINS[5]= { 9, 10, 11, 12, 13 };

const float MIDI_MAX_VAL = 127;
const int CHANNEL = 1;

const int MIDI_START_K = 0x20;
const int MIDI_START_L = 0x30;
const int MIDI_START_B = 0x40;

int k_values[sizeof(K_PINS)];
bool b_values[sizeof(K_PINS)];
bool l_values[sizeof(L_PINS)];

void setup() {
  MIDI.begin(1);

//  Serial.begin(9600);

  for (int i = 0; i < sizeof(K_PINS); i++) {
    pinMode(K_PINS[i], INPUT);
  }

   for (int i = 0; i < sizeof(B_PINS); i++) {
    pinMode(B_PINS[i], INPUT);
  }

   for (int i = 0; i < sizeof(L_PINS); i++) {
    pinMode(L_PINS[i], OUTPUT);
  }

  MIDI.setHandleControlChange(handleControl);
}

int knobToVelocity(float value) {
  float out = (value * MIDI_MAX_VAL) / K_MAX;
  return floor(max(0, min(MIDI_MAX_VAL, out)));
}

void updateKnob(int i) {
  int prev = k_values[i];
  int val = knobToVelocity(analogRead(K_PINS[i]));

  if (abs(val - prev) > K_THRESHOLD) {
    MIDI.sendControlChange(MIDI_START_K + i, val, CHANNEL);
    k_values[i] = val;
  }
}

void updateLed(int i) {
  int prev = k_values[i];
  int val = knobToVelocity(analogRead(K_PINS[i]));

  digitalWrite(L_PINS[i], l_values[i] ? HIGH : LOW);
}

void handleControl(byte channel, byte control, byte value) {
  if (control >= MIDI_START_L && control < MIDI_START_L + sizeof(L_PINS)) {
    int i = control - MIDI_START_L;
    
    l_values[i] = value > 0;
  }
}

void updateButton(int i) {
  bool val = digitalRead(B_PINS[i]);
  bool prev = b_values[i];

  if (val != prev) {
    MIDI.sendControlChange(MIDI_START_B + i, val, CHANNEL);
    b_values[i] = val;
  }
}


void loop() {
  MIDI.read();
  
  for (int i = 0; i < sizeof(K_PINS); i++) {
    updateKnob(i);
  }
  
  for (int i = 0; i < sizeof(B_PINS); i++) {
    updateButton(i);
  }

  for (int i = 0; i < sizeof(L_PINS); i++) {
    updateLed(i);
  }
  
  delay(1);
}

midi-ino.js

const MI = {
  previewPlaying: false,
  previewToMiddleOnLoad: false,
};

const GROUPS = { PREVIEW: "[PreviewDeck1]" };
const MAX_POSITION = 1.14;
const LED_MIDI_START = 0x30;
const MIDI_ON = 0x7f;
const MIDI_OFF = 0x00;

MI.init = function () {
  engine.makeConnection(GROUPS.PREVIEW, "track_loaded", handlePreviewLoaded);
};

MI.shutdown = function () {};

function handlePreviewLoaded(channel, group) {
  if (MI.previewToMiddleOnLoad) {
    MI.previewToMiddleOnLoad = false;
    engine.setValue(GROUPS.PREVIEW, "playposition", MAX_POSITION / 2);
  }
}

function setLed(index, status) {
  midi.sendShortMsg(0xb0, LED_MIDI_START + index, status ? MIDI_ON : MIDI_OFF);
}

MI.togglePreviewFromTheMiddle = function (channel, group, value) {
  const pressed = value;
  const playing = engine.getValue(GROUPS.PREVIEW, "play");

  if (!pressed) {
    setLed(2, false);
    return engine.setValue(GROUPS.PREVIEW, "play", false);
  }

  MI.previewToMiddleOnLoad = true;
  setLed(2, true);
  script.triggerControl(GROUPS.PREVIEW, "LoadSelectedTrackAndPlay", true);
};

midi-ino.midi.xml

<?xml version='1.0' encoding='utf-8'?>
<MixxxControllerPreset schemaVersion="1" mixxxVersion="2.0.0+">
    <info>
        <name>MIDI-Ino (Custom)</name>
        <author>Tanc</author>
    </info>

    <controller id="MIDI-ino">
        <scriptfiles>
            <file filename="midi-ino.js" functionprefix="MI"/>
        </scriptfiles>

        <controls>
          <control>
              <group>[EffectRack1_EffectUnit1_Effect1]</group>
              <key>meta</key>
              <status>0xB0</status>
              <midino>0x20</midino>
              <options>
                  <Invert />
              </options>
          </control>
          <control>
              <group>[EffectRack1_EffectUnit1_Effect1]</group>
              <key>enabled</key>
              <status>0xB0</status>
              <midino>0x40</midino>
              <options>
                  <Normal />
              </options>
          </control>

          <control>
              <group>[EffectRack1_EffectUnit1_Effect2]</group>
              <key>meta</key>
              <status>0xB0</status>
              <midino>0x21</midino>
              <options>
                  <Invert />
              </options>
          </control>
          <control>
              <group>[EffectRack1_EffectUnit1_Effect2]</group>
              <key>enabled</key>
              <status>0xB0</status>
              <midino>0x41</midino>
              <options>
                  <Normal />
              </options>
          </control>

          <control>
              <description>Knob 3 (middle)</description>
              <group>[Master]</group>
              <key>headMix</key>
              <status>0xB0</status>
              <midino>0x22</midino>
              <options>
                  <Normal />
              </options>
          </control>
          <control>
              <description>Button 3 (middle)</description>
              <group>[PreviewDeck1]</group>
              <key>MI.togglePreviewFromTheMiddle</key>
              <status>0xB0</status>
              <midino>0x42</midino>
              <options>
                  <script-binding/>
              </options>
          </control>

          <control>
              <group>[EffectRack1_EffectUnit2_Effect1]</group>
              <key>meta</key>
              <status>0xB0</status>
              <midino>0x23</midino>
              <options>
                  <Normal />
              </options>
          </control>
          <control>
              <group>[EffectRack1_EffectUnit2_Effect1]</group>
              <key>enabled</key>
              <status>0xB0</status>
              <midino>0x43</midino>
              <options>
                  <Normal />
              </options>
          </control>

          <control>
              <group>[EffectRack1_EffectUnit2_Effect2]</group>
              <key>meta</key>
              <status>0xB0</status>
              <midino>0x24</midino>
              <options>
                  <Invert />
              </options>
          </control>
          <control>
              <group>[EffectRack1_EffectUnit2_Effect2]</group>
              <key>enabled</key>
              <status>0xB0</status>
              <midino>0x44</midino>
              <options>
                  <Normal />
              </options>
          </control>
        </controls>

        <outputs>
            <output>
                <group>[EffectRack1_EffectUnit1_Effect1]</group>
                <key>enabled</key>
                <status>0xB0</status>
                <midino>0x30</midino>
                <on>0x7F</on>
                <off>0x00</off>
                <minimum>0.5</minimum>
            </output>

            <output>
                <group>[EffectRack1_EffectUnit1_Effect2]</group>
                <key>enabled</key>
                <status>0xB0</status>
                <midino>0x31</midino>
                <on>0x7F</on>
                <off>0x00</off>
                <minimum>0.5</minimum>
            </output>

            <output>
                <group>[EffectRack1_EffectUnit1_Effect3]</group>
                <key>enabled</key>
                <status>0xB0</status>
                <midino>0x32</midino>
                <on>0x7F</on>
                <off>0x00</off>
                <minimum>0.5</minimum>
            </output>


            <output>
                <group>[EffectRack1_EffectUnit2_Effect1]</group>
                <key>enabled</key>
                <status>0xB0</status>
                <midino>0x33</midino>
                <on>0x7F</on>
                <off>0x00</off>
                <minimum>0.5</minimum>
            </output>


            <output>
                <group>[EffectRack1_EffectUnit2_Effect2]</group>
                <key>enabled</key>
                <status>0xB0</status>
                <midino>0x34</midino>
                <on>0x7F</on>
                <off>0x00</off>
                <minimum>0.5</minimum>
            </output>
        </outputs>
    </controller>
</MixxxControllerPreset>