Controlling a matrix of LEDs

[JovoSK]

Hi folks,

I'm attempting to gain individual control over a matrix of LEDs, such that they would be individually toggle-able via MIDI message. I'm pretty (read: very) new to this. Matrix is 10x5 and on PCB, which makes it awkward to try to retrofit a MAX7219 in.

My thought is to array the LEDs, but I'm unsure of how to proceed.

Any advice would be greatly appreciated.

Thanks!

EDIT

After some further research, I found this:

/*
 * _8x8 LED matrix
 *
 * (c) 2009 BlushingBoy.net
 */

#include "TimerOne.h"

byte rows[8] = {9, 14, 8, 12, 1, 7, 2, 5};
byte cols[8] = {13, 3, 4, 10, 6, 11, 15, 16};
byte pins[16] = {5, 4, 3, 2, 14, 15, 16, 17, 13, 12, 11, 10, 9, 8, 7, 6};
byte screen[8] = {0, 0, 0, 0, 0, 0, 0, 0};
volatile byte screenRow = 0;
volatile byte screenCol = 0;

void setup() {
  Timer1.initialize(100);
  for (int i = 2; i <= 17; i++)
    pinMode(i, OUTPUT);
  Timer1.attachInterrupt(doubleBuffer);
}

// interrupt routine
void doubleBuffer() {
  // reset the previous iteration
  digitalWrite(translatePin(rows[screenRow]), HIGH); // set previous off
  digitalWrite(translatePin(cols[screenCol]), LOW);  // set previous off
  // go to the next iteration...
  // go to the next screenCol, wrap if necessary
  screenCol++;
  if (screenCol >= 8) {
    screenCol = 0;
    // when screenCol wraps, go to the next screenRow, wrap if necessary
    screenRow++;
    if (screenRow >= 8) {
      screenRow = 0;
    }
  }
  // set this iteration
  if((screen[screenRow]>>screenCol)&B1 == B1) {
    digitalWrite(translatePin(rows[screenRow]), LOW);  // set this on
    digitalWrite(translatePin(cols[screenCol]), HIGH); // set this on
  } else {
    digitalWrite(translatePin(rows[screenRow]), HIGH); // set this off
    digitalWrite(translatePin(cols[screenCol]), LOW);  // set this off
  }
}

byte translatePin(byte original) {
  return pins[original - 1];
}

void allOFF() {
  for (int i = 0; i < 8; i++)
    screen[i]=0;
}

void on(byte row, byte column) {
    screen[column-1] |= (B1<<(row-1));
}

void off(byte row, byte column) {
    screen[column-1] &= ~(B1<<(row-1));
}

Source: https://playground.arduino.cc/Main/DirectDriveLEDMatrix/?fbclid=IwAR3BCcRQW4homrzA1M3msrANngjVmotSv2Xv7VfaTd2U4r5nTxAFkYVlZpc

This seems to do what I want in regards to interacting with the matrix. The follow up then is, how do I integrate the CS library in, such that when the Arduino receives a note from the PC, it fires the appropriate LEDs?

[tttapa]

I'd recommend using the new-input branch of this library.

Then you can implement your own NoteLED class that matches incoming MIDI note messages and turns on/off an LED accordingly:

Control-Surface/src/MIDI_Inputs/LEDs/NoteCCKPLED.hpp

Lines 10 to 56 in a061a3a

	/// Generic base class for classes that listen for MIDI Note, Control Change and
	/// Key Pressure events on a single address and turns on an LED when the value
	/// is higher than a threshold.
	///
	/// @tparam Type
	/// The type of MIDI messages to listen for:
	/// - MIDIMessageType::NOTE_ON
	/// - MIDIMessageType::CONTROL_CHANGE
	/// - MIDIMessageType::KEY_PRESSURE
	template <MIDIMessageType Type>
	class NoteCCKPLED : public MatchingMIDIInputElement<Type, TwoByteMIDIMatcher> {
	public:
	using Matcher = TwoByteMIDIMatcher;
	using Parent = MatchingMIDIInputElement<Type, Matcher>;
	/// @param ledPin
	/// The output pin with the LED connected.
	/// @param address
	/// The address to listen to.
	NoteCCKPLED(pin_t ledPin, MIDIAddress address)
	: Parent(address), ledPin(ledPin) {}
	private:
	void handleUpdate(typename Matcher::Result match) override {
	PinStatus_t state = match.value >= threshold ? HIGH : LOW;
	AH::ExtIO::digitalWrite(ledPin, state);
	}
	public:
	/// Set the pinmode of the LED to OUTPUT.
	void begin() override {
	AH::ExtIO::pinMode(ledPin, OUTPUT);
	AH::ExtIO::digitalWrite(ledPin, LOW);
	}
	/// Turn off the LED.
	void reset() override { AH::ExtIO::digitalWrite(ledPin, LOW); }
	/// Get the LED threshold.
	uint8_t getThreshold() const { return threshold; }
	/// Set the LED threshold. LED will be on if `getValue() >= getThreshold()`.
	void setThreshold(uint8_t threshold) { this->threshold = threshold; }
	private:
	pin_t ledPin;
	uint8_t threshold = 0x01;
	};

Replace the calls to digitalWrite on lines 35 and 46 by calls to the on() or off() function in your sketch to turn on/off the correct LED. You can probably leave the begin() method empty.