Shadow spot on 16x32 RGB Matrix

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Alkerion
 
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Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

I've been easily able to get test examples to works on my new 16x32 RGB Matrix, but I've some ghosting on line 1 and 9.

It seems to me that line 8 is copied on line 1 and line 16 on line 9

Image

Image

Image


I use an Arduino Mega, I've checked 10 time the wiring, everything is OK.

What could be wrong ?

Regards

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

OK, I've been able to determine that it is probably not due to a hardware defect because there is no such issue if I display simple static shapes or text.

Any idea what's going wrong with the demos ?

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

I've continued to investigate why I've this side effect, and I've been able to reproduce it.

This is finally probably due to defective hardware.


This problem only occurs when I use LED_x_HIGH intensity.

With this intensity the LED below the active LED is also activated (valid for row 1 to 7), and when on row 8, it's LED on row 1 that is activated too.

Image

Image

Please test with your boards and let me know if you face the same issue.

I'll contact after sales service to return my matrix.

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

I've played with a 64x32 matrix I also have, matrix with which I've never had such issues.

By playing a lot with all codes, both Matrix and different Arduino I made a little mistake and declared my 64x32 matrix like that :

RGBmatrixPanel *matrix = new RGBmatrixPanel(A, B, C, D, CLK, LAT, OE, true); (I forgot the ,64)

And obtained:
Image
Image
Image

The exact same problem appears on the left panel...

With the correct declaration :

RGBmatrixPanel *matrix = new RGBmatrixPanel(A, B, C, D, CLK, LAT, OE, true, 64);

I obtained:
Image
Image

I'm just asking myself if it's the matrix having a problem or if there is a bug with your library.


The matrix behave the same on a UNO or a MEGA.


I'm looking forward for your reply.

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adafruit_support_carter
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by adafruit_support_carter »

Let's look at the 16x32 matrix first. What sketch were you running in your test cases?

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

I've tested all your demos and the following test with lines :

Code: Select all

#include <RGBmatrixPanel.h>

#define CLK 11
#define OE   9
#define LAT 10
#define A   A0
#define B   A1
#define C   A2
#define LED_BLACK           0
#define LED_RED_VERYLOW    (3 <<  11)
#define LED_RED_LOW        (7 <<  11)
#define LED_RED_MEDIUM     (15 << 11)
#define LED_RED_HIGH       (31 << 11)

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

int i = 0;

void setup() {
	matrix.begin();
	matrix.setTextWrap(false); // Allow text to run off right edge
}

void loop() {
	matrix.fillScreen(LED_BLACK);
	matrix.drawLine(0, i, 32, i, LED_RED_HIGH); //Line 1
	delay(1000);
	i++;
	
	if(i > 16)
		i = 0;

	matrix.swapBuffers(true);
}
Regards

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adafruit_support_carter
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by adafruit_support_carter »

I use an Arduino Mega, I've checked 10 time the wiring, everything is OK.
How exactly are you wiring it to the Mega? With a breakout shield and ribbon cable? Jumpered wire-to-wire? etc.
I've tested all your demos and the following test with lines :
Let's work with just one demo. What's the simplest of the examples that exhibits this behavior? Which one of these?
https://github.com/adafruit/RGB-matrix- ... r/examples

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

HI!

All the demos are doing that, my code on previous post is the simplest code that exhibits the behavior.

It's connected like that :
Image

Regards

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adafruit_support_carter
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by adafruit_support_carter »

Direct connect hand wiring. That can be problematic and very difficult to troubleshoot. We really recommend using one of the RGB matrix shields so you can use a ribbon cable directly between the board and the matrix.

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi,

The cables are OK, no issue on this side for me, checked many times and my other 64x32 panel is working perfect with them.

The problem ONLY occurs with LED set to max intensity, on Medium no problem.

Question is, do you have the same problem on your side with 16x32 panel ?

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adafruit_support_carter
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by adafruit_support_carter »

Hey - sorry for the delay. I was asking around about this. Apparently this behavior is something that is generally expected and is related to how we are driving the displays.

We'll update our Learn guide to mention this.

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Alkerion
 
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Re: Shadow spot on 16x32 RGB Matrix

Post by Alkerion »

Hi !

Thanks for your feedback, sadly this will make the panels unusable if it occurs with all of them.

It's really strange that I haven't this issue with my 64x32 panel (with same boards and cables) and that no one else is reporting this issue.

Your support team send me a RMA number for an exchange, I'll keep you in touch.

Regards

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