Custom-Note-LED-Input-Element-Callback-FastLED.ino

Custom-Note-LED-Input-Element-Callback-FastLED

This example demonstrates how to attach custom callbacks to Note or Control Change MIDI Input Elements.

Boards:

AVR, AVR USB, Due, Nano 33, Teensy 3.x, ESP32

Connections

• Pin 2: The data pin of a Neopixel LED strip with (at least) 8 LEDs

Behavior

If a MIDI Note On event for note 0x3C (C4 or middle C) is sent, its velocity value sets the red value of the first LED, note 0x3D controls the green value of the first LED, note 0x3E controls the blue value of the first LED, note 0x3F controls the red value of the second LED, 0x40 controls the green value of the second LED, etc.

Mapping

Route the MIDI output of a MIDI keyboard to the Arduino's MIDI input. Then play some notes in the two octaves above middle C.
Alternatively, map it in you DAW, for example, in VirtualDJ:
<color notered="0x3C" notegreen="0x3D" noteblue="0x3E" ... />

Written by PieterP, 2020-03-12
https://github.com/tttapa/Control-Surface

 
#include <FastLED.h>
#include <Control_Surface.h> // Include the Control Surface library
 
// Instantiate a MIDI over USB interface.
USBMIDI_Interface midi;
 
using namespace MIDI_Notes;
 
// Custom callback to handle incoming note events and control the LEDs
class NoteCCFastLEDCallbackRGB : public SimpleNoteCCValueCallback {
  public:
    NoteCCFastLEDCallbackRGB(CRGB *ledcolors)
        : ledcolors(ledcolors) {}
 
    // Called once upon initialization.
    void begin(const INoteCCValue &input) override { updateAll(input); }
 
    // Called each time a MIDI message is received and an LED has to be updated.
    // @param   input
    //          The NoteCCRange or NoteCCValue object this callback belongs to.
    //          This is the object that actually receives and stores the MIDI
    //          values.
    // @param   index
    //          The index of the value that changed. (zero-based)
    void update(const INoteCCValue &input, uint8_t index) override {
        // Get the MIDI value that changed [0, 127]
        uint8_t value      = input.getValue(index);
        uint8_t ledIndex   = index / 3;
        uint8_t colorIndex = index % 3;
        // Update the LED color
        ledcolors[ledIndex][colorIndex] = value;
    }
 
  private:
    // Pointer to array of FastLED color values for the LEDs
    CRGB *ledcolors;
};
 
// Create a type alias for the MIDI Note Input Element that uses
// the custom callback defined above.
template <uint8_t RangeLen>
using CustomNoteValueLED = GenericNoteCCRange<MIDIInputElementNote, 
                                              RangeLen, 
                                              NoteCCFastLEDCallbackRGB>;
 
// Define the array of leds.
Array<CRGB, 8> leds = {};
// The data pin with the strip connected.
constexpr uint8_t ledpin = 2;
 
// Create a MIDI input element that listens to all notes in the range C4 - B5
// (the range starts at C4 and has a length equal to `leds.length * 3` == 24).
// Note C4 is the red channel of the first LED,
// Note C#4 is the green channel of the first LED,
// Note D4 is the blue channel of the first LED,
// Note D#4 is the red channel of the second LED, etc.
CustomNoteValueLED<leds.length * 3> midiled = {note(C, 4), leds.data};
 
void setup() {
  // See FastLED examples and documentation for more information.
  FastLED.addLeds<NEOPIXEL, ledpin>(leds.data, leds.length);
  FastLED.setCorrection(TypicalPixelString);
  FastLED.setBrightness(128);
  Control_Surface.begin();
}
 
void loop() {
  Control_Surface.loop();
  FastLED.show();
}