Question about grouping WS2812B LEDS.

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1

Question about grouping WS2812B LEDS. Right now i am working with a small 5x5 LED matrix arranged in a horizontal snake pattern starting at the top left (See picture bellow). What i would like to do is display small animations/ pixel art onto the matrix. For instance if i wanted to display the letter “X” on the matrix I would simply write it as
void loop() {
leds[6] = CRGB:: Red;
leds[8] = CRGB:: Red;
leds[12] = CRGB:: Red;
leds[16] = CRGB:: Red;
leds[18] = CRGB:: Red;
FastLED.show();
FastLED.delay(10);
}
What i am wondering is if there is a way to simplify this code so that i don’t have to manually assigning each led. Is it possible to group these Leds into their own array and then assign that array to the color Red?

72fe8503874af4b05ba940b01f6a3600.png

2

It might be daunting at first if this is your your first WS2812 matrix project, but it might be worth taking a crack at: There are a few font libraries that you can add - so that you can have a function that you pass a character to, and it will return a matrix (in this example 6x9) with the proper pixels illuminated to make the character. Of course, this particular library needs a bigger matrix than your 5x5

But if you don’t want to get complicated, I think you just want to ask if you can assign an array of indexes… you should be able to do that.

int letterx[5] = {6,8,12,16,18};

FastLED.clear();

for(int i =0; i<5;i++){
leds[letterx[i]] = CRGB::Red;
}

that what you’re looking for?

3

[Sorry, got delayed] You could also put your pixel numbers in an array and do something like this:

int letterX [5] = { 6,8,12,16,18 };
uint8_t sizeX = sizeof(letterX)/sizeof(letterX[0]);

for (uint8_t i=0; i<sizeX; i++) {
leds[ letterX[i] ] = CRGB::White;
}

4

Hi @Reed_Jeandell - Check out Aaron Liddiment"s Github LEDText library at:

Look at example 4. This should allow you to do what you want to do on your matrix.

5

@marmil Yup - I was editing my suggestion when you posted this. Realized that Reed was probably just looking for the leds[letterx[i]] suggestion

6

@chad_steinglass Good to have many options. :smiley:

7

@marmil Thank you, this is exactly what i was looking for.