10.Note-FastLED-ColorMapper.ino

10.Note-FastLED-ColorMapper

This example demonstrates the use of addressable LEDs that respond to incoming MIDI note events. This example uses a custom color mapper to get a rainbow effect across the LED strip.

Boards: 🛈

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

Note

You might lose incoming MIDI data while the LED strip is being updated. To avoid this, don't use an Arduino UNO.
See https://github.com/FastLED/FastLED/wiki/Interrupt-problems

Connections

• 2: Data pin of NeoPixel LED strip with at least 8 pixels.

Behavior

If a MIDI Note On event for note 0x3C (C4 or middle C) is sent, the first LED will light up, if a Note Off event for that note is sent, the LED will turn off.
If a MIDI Note On event for note 0x3D (C#4) is sent, the second LED will light up, etc.
(A Note On event with a velocity of zero also counts as a Note Off event.)

Mapping

Route the MIDI output of a MIDI keyboard to the Arduino's MIDI input. Then play a middle C and some notes above it on the keyboard.

Written by PieterP, 2019-10-15
https://github.com/tttapa/Control-Surface

 
#include <FastLED.h>
// Must be before Control Surface to enable FastLED features of Control Surface
#include <Control_Surface.h>
 
// Define the array of leds.
Array<CRGB, 8> leds {};
// The data pin with the strip connected.
constexpr uint8_t ledpin = 2;
 
USBMIDI_Interface midi;
 
// Create a functor that maps the velocity and the index of a note to a color.
struct RainbowColorMapper {
  CHSV operator()(uint8_t velocity, uint8_t index) const {
    return CHSV(255 * index / leds.length, 255, 255u * velocity / 127u);
  }
};
 
NoteRangeFastLED<leds.length, RainbowColorMapper> midiled {
  leds,
  MIDI_Notes::C[4],
};
 
void setup() {
  // See FastLED examples and documentation for more information.
  FastLED.addLeds<NEOPIXEL, ledpin>(leds.data, leds.length);
  FastLED.setCorrection(TypicalPixelString);
  midiled.setBrightness(128);
  Control_Surface.begin();
}
 
void loop() {
  Control_Surface.loop();
  if (midiled.getDirty()) { // If the colors changed
    FastLED.show();         // Update the LEDs with the new colors
    midiled.clearDirty();   // Clear the dirty flag
  }
}