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Thread: Example code for MIDI controllers with Pots and Buttons

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  1. #1
    Senior Member oddson's Avatar
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    Example code for MIDI controllers with Pots and Buttons

    Here is my code for a simple MIDI controller with both potentiometers and buttons using ResponsiveAnalogRead and BOUNCE libraries to deal with signal stability.

    I hope it will be helpful for those looking to implement basic USB-MIDI controller projects and don't want to write their own code as yet.

    I'm looking for suggestions and a general vetting for stupidity before pointing noobs at it...

    Code:
    //************LIBRARIES USED**************
    // include the ResponsiveAnalogRead library for analog smoothing
    #include <ResponsiveAnalogRead.h>
    // include the Bounce library for 'de-bouncing' switches -- removing electrical chatter as contacts settle
    #include <Bounce.h> 
    //usbMIDI.h library is added automatically when code is compiled as a MIDI device
    
    // ******CONSTANT VALUES******** 
    // customize code behaviour here!
    const int channel = 1; // MIDI channel
    const int A_PINS = 6; // number of Analog PINS
    const int D_PINS = 3; // number of Digital PINS
    const int ON_VELOCITY = 99; // note-one velocity sent from buttons (should be 65 to  127)
    
    // define the pins you want to use and the CC ID numbers on which to send them..
    const int ANALOG_PINS[A_PINS] = {A0,A1,A2,A3,A4,A5};
    const int CCID[A_PINS] = {21,22,23,24,25,26};
    
    // define the pins and notes for digital events
    const int DIGITAL_PINS[D_PINS] = {0,1,2};
    const int note[D_PINS] = {60,61,62};
    const int BOUNCE_TIME = 7; // 5 ms is usually sufficient
    const boolean toggled = true;
    
    
    //******VARIABLES***********
    // a data array and a lagged copy to tell when MIDI changes are required
    byte data[A_PINS];
    byte dataLag[A_PINS]; // when lag and new are not the same then update MIDI CC value
    
    
    //************INITIALIZE LIBRARY OBJECTS**************
    // not sure if there is a better way... some way run a setup loop on global array??
    // use comment tags to comment out unused portions of array definitions
    
    // initialize the ReponsiveAnalogRead objects
    ResponsiveAnalogRead analog[]{
      {ANALOG_PINS[0],true},
      {ANALOG_PINS[1],true},
      {ANALOG_PINS[2],true},
      {ANALOG_PINS[3],true},
      {ANALOG_PINS[4],true},
      {ANALOG_PINS[5],true}/*,
      {ANALOG_PINS[6],true},
      {ANALOG_PINS[7],true},*/
    }; 
    
    // initialize the bounce objects 
    Bounce digital[] =   {
      Bounce(DIGITAL_PINS[0],BOUNCE_TIME), 
      Bounce(DIGITAL_PINS[1], BOUNCE_TIME),
      Bounce(DIGITAL_PINS[2], BOUNCE_TIME)/*,
      Bounce(DIGITAL_PINS[3], BOUNCE_TIME),
      Bounce(DIGITAL_PINS[4], BOUNCE_TIME),
      Bounce(DIGITAL_PINS[5], BOUNCE_TIME),
      Bounce(DIGITAL_PINS[6], BOUNCE_TIME),
      Bounce(DIGITAL_PINS[7], BOUNCE_TIME),*/
    }; 
    
    //************SETUP**************
    void setup() {
    // loop to configure input pins and internal pullup resisters for digital section
      for (int i=0;i<D_PINS;i++){
        pinMode(DIGITAL_PINS[i], INPUT_PULLUP);
      }
    }
    
    //************LOOP**************
    void loop() {
      getAnalogData();
      getDigitalData();
      while (usbMIDI.read()) {
         // controllers must call .read() to keep the queue clear even if they are not responding to MIDI
      }
    }
    
    
    //************ANALOG SECTION**************
    void getAnalogData(){  
      for (int i=0;i<A_PINS;i++){
        // update the ResponsiveAnalogRead object every loop
        analog[i].update(); 
        // if the repsonsive value has change, print out 'changed'
        if(analog[i].hasChanged()) {
          data[i] = analog[i].getValue()>>3;
          if (data[i] != dataLag[i]){
            dataLag[i] = data[i];
            usbMIDI.sendControlChange(CCID[i], data[i], channel);
          }
        }
      }
    }
    
    
    
    //************DIGITAL SECTION**************
    void getDigitalData(){
      for (int i=0;i<D_PINS;i++){
      digital[i].update();
        if (digital[i].fallingEdge()) {
          usbMIDI.sendNoteOn(note[i], ON_VELOCITY, channel);  
        }
        // Note Off messages when each button is released
        if (digital[i].risingEdge()) {
          usbMIDI.sendNoteOff(note[i], 0, channel);  
        }
      }
    }
    Last edited by oddson; 07-15-2017 at 08:30 PM.

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