Displaying basic text on an LCD matrix

Other Hardware Displays
1

Hi, I'm very much a beginner with Arduinos (or is that Arduini). I have a UNO and a WS2812B LCD matrix. I've got the hang of lighting the LEDs up in various ways using the FastLED library, and now I'd like to display some text. Presumably all I need is a "font" in the form of lots of predefined arrays to form each letter and number - presumably these also come in different sizes 8x8, 8x5, 7x5 etc. There seem to be all sorts of libraries around like AdaFruit GFX but I get the impression these are more complicated than I need to start with. Can anyone advise?

2

I don't know if this is what you want, but check out this YouTube video, Scrolling Text using a Chinese 8x32 WS2812B LED MATRIX neopixel.

The sketch it uses does use the Adafruit libraries, but the sketch itself is really quite simple.

#include <Adafruit_GFX.h>
#include <Adafruit_NeoMatrix.h>
#include <Adafruit_NeoPixel.h>

#define PIN 9

Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(32, 8, PIN,
  NEO_MATRIX_TOP    + NEO_MATRIX_LEFT +
  NEO_MATRIX_COLUMNS + NEO_MATRIX_ZIGZAG,
  NEO_GRB            + NEO_KHZ800);

const uint16_t colors[] = {
  matrix.Color(204, 0, 204), matrix.Color(204, 204, 0), matrix.Color(0, 255, 255),
  matrix.Color(255, 10, 127), matrix.Color(127, 0, 255), matrix.Color(0, 255, 0),
  matrix.Color(255, 99, 255)};

void setup() {
  matrix.begin();
  matrix.setTextWrap(false);
  matrix.setBrightness(40);
  matrix.setTextColor(colors[0]);
}

int x = matrix.width();
int pass = 0;

void loop() {
  matrix.fillScreen(0);    //Turn off all the LEDs
  matrix.setCursor(x, 0);
  matrix.print(F("MOJO+TAHI 6-28-20"));

  if( --x < -110 ) {
    x = matrix.width();

    if(++pass >= 8) pass = 0;
    matrix.setTextColor(colors[pass]);
  }
  matrix.show();
  delay(33);
}
3

Thanks Mr Y. I'm using a 16x16 array while I wait for something better to arrive in the post, but once I'd tweaked the Adafruit_NeoMatrix constructor a bit it worked a treat. I do have a question however: I found the fonts in the Adafruit_GFX_Library folder, with all the files containing lots of arrays of font data, just as I expected, but I couldn't work out how my sketch specified which font to use. There are obviously lots to choose from, but I couldn't work out where in the code the font is specified. As a (retired) developer I like to know how these things work. Can you enlighten me?

4

This article may be of help.

Also, this is the documentation for the Adafruit GFX library.

5

Brilliant. Thanks

6

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