Adafruit 32x32 matrix - drawing images

Projects General Guidance
1

Hi there!

I'm brand brand new to Arduino, but I had seen several tutorials for drawing pixel-based images by building a LED matrix.

Well, I purchased the 32x32 matrix, and I have found some basic drawing commands in the Adafruit library, however I am trying to draw an image of my own.

The matrix is hooked up to an Arduino Uno with the RGB Matrix Shield from Adafruit.

I've found that I can't just code every single pixel one by one since that takes up too much memory.

I've seen other people do it, but I can't figure out how to assign values to each of the pixels.
I have a 32x32 set of images, and I can even convert those images to RGB values, but I can't figure out how to draw those values to the screen.

Any advice?

2

If the image is static, use PROGMEM.
Each image will occupy 3072 bytes, so you should be able to store a few.

3

Amazing - I figured out a way to store the individual values to PROGMEM now, but how do I go about drawing those items onto the screen? My apologies if that is too big of a question.

4

By reading them out of PROGMEM (instead of RAM) and writing them to your display driver.

5

I have my code below (so far) below.
I stored the values to PROGMEM - could you please help with the sending to the matrix portion?

These are my very first few weeks of coding at all.

I appreciate it so much!

#include <Adafruit_GFX.h> // Core graphics library
#include <RGBmatrixPanel.h> // Hardware-specific library

#define CLK 8 // MUST be on PORTB! (Use pin 11 on Mega)
#define OE 9
#define LAT 10
#define A A0
#define B A1
#define C A2
#define D A3

RGBmatrixPanel matrix(A, B, C, D, CLK, LAT, OE, false);

void setup() {
// put your setup code here, to run once:

static const int8_t MM1 PROGMEM = {0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x01, 0x00, 0x00, 0xff, 0x0a, 0x0d, 0x0e, 0xff, 0x1f, 0x27, 0x2a, 0xff, 0x20, 0x28, 0x27, 0xff, 0x07, 0x08, 0x08, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x09, 0x08, 0x07, 0xff, 0x0a, 0x05, 0x13, 0xff, 0x27, 0x4a, 0x83, 0xff, 0x69, 0xc5, 0xf3, 0xff, 0x88, 0xf5, 0xfc, 0xff, 0x40, 0x6c, 0x73, 0xff, 0x09, 0x07, 0x0f, 0xff, 0x04, 0x03, 0x04, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x08, 0x06, 0x06, 0xff, 0x1d, 0x1e, 0x43, 0xff, 0x0c, 0x43, 0xde, 0xff, 0x03, 0x3c, 0xc8, 0xff, 0x34, 0x60, 0xab, 0xff, 0x6a, 0xc5, 0xf7, 0xff, 0x88, 0xf6, 0xff, 0xff, 0x4a, 0x81, 0xbf, 0xff, 0x11, 0x12, 0x37, 0xff, 0x03, 0x01, 0x03, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x03, 0x01, 0x00, 0xff, 0x1d, 0x1b, 0x2e, 0xff, 0x12, 0x3e, 0xd1, 0xff, 0x00, 0x61, 0xf2, 0xff, 0x02, 0x7d, 0xd6, 0xff, 0x08, 0x41, 0xaf, 0xff, 0x2d, 0x51, 0xb3, 0xff, 0x69, 0xcb, 0xfb, 0xff, 0x88, 0xff, 0xff, 0xff, 0x3f, 0x81, 0xcb, 0xff, 0x0e, 0x12, 0x33, 0xff, 0x03, 0x02, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00};

}

void loop() {
// put your main code here, to run repeatedly:

}

6

Start here

You probably don't want to limit the scope of the image to just setup ()

7

Yes, I realized my mistake and moved that above the setup.

It's the setup where I'm stuck. I looked at that PROGMEM link to figure out how to set the pixel information as a stored variable.

Now, I am needing to figure out how to write that information to the screen.

8

Probably a pixel at a time.

This could be a good time to investigate the AVR 24 bit datatype

9

I tried to write it a pixel a a time, but the code needed to write one line of lit pixels was over 60% of the memory.

Thanks for your help. I'll continue banging my head against this wall.