One LED, many notes?

[fitzgreyve]

NoteLED lights a single LED if a specific single MIDI note message is recieved.

What's the simplest way to light one (and only one!) LED if a note is recieved within a specific range. For example any note C(1) to C(5) on channel_1 ?

Many thanks.

[tttapa]

When should the LED be turned off?

[fitzgreyve]

I don't mind, when any note off is received would be fine.

[tttapa]

You could try something like this (untested):

#include <Control_Surface.h> // Include the Control Surface library

// Instantiate a MIDI over USB interface.
USBMIDI_Interface midi;

// MIDI Input Element that listens for a range of MIDI Note events and turns
// on/off the LED if the velocity is above/below the threshold.

class CustomNoteLED
  // First, inherit from the MatchingMIDIInputElement base class. Indicate that
  // you want to listen to a range of MIDI Note events by specifying the MIDI
  // message type, and use a 2-byte range MIDI message matcher, since MIDI Note
  // events have two data bytes.
  : public MatchingMIDIInputElement<MIDIMessageType::NoteOn,
                                    TwoByteRangeMIDIMatcher> {
 public:
  // Constructor
  CustomNoteLED(pin_t ledPin, MIDIAddress address, uint8_t range_len)
    : MatchingMIDIInputElement({address, range_len}), ledPin(ledPin) {}

  // Called once upon initialization, set up the pin mode for the LED.
  void begin() override { ExtIO::pinMode(ledPin, OUTPUT); }

  // Called when an incoming MIDI Note message matches this element's matcher
  // (i.e. it has the right MIDI address, channel and cable).
  // The match object that's passed as a parameter contains the velocity value
  // of the Note message that matched.
  void handleUpdate(TwoByteRangeMIDIMatcher::Result match) override {
    ExtIO::digitalWrite(ledPin, match.value >= threshold ? HIGH : LOW);
  }

  // Called when the input element is reset (e.g. by an "All notes off" MIDI
  // event).
  void reset() override { ExtIO::digitalWrite(ledPin, LOW); }

 private:
  pin_t ledPin;
  const static uint8_t threshold = 0x01;
};

// Instantiate the LED that will light up when any note from C1 to C5 is
// playing.
CustomNoteLED led {
  LED_BUILTIN,                   // Pin with the LED connected
  {MIDI_Notes::C(1), Channel_1}, // Note C1 on MIDI channel 1
  MIDI_Notes::C(5) - MIDI_Notes::C(1), // Length of the range
};

void setup() {
  Control_Surface.begin(); // Initialize Control Surface
}

void loop() {
  Control_Surface.loop(); // Update the Control Surface
}

[fitzgreyve]

Many thanks, I'll give that a try

[fitzgreyve]

Works well, and a good starting point for further modification - many thanks.