64x32 LED Matrix

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LEDLED
 
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64x32 LED Matrix

Post by LEDLED »

Hello - I am writing about Order 801117. When the LED matrix is powered, and the ribbon cable (without Arduino connected) is attached, the LED matrix goes wild. Different rows and colors flicker, squares and lines appear and disappear, and so on.

When the Arduino is plugged into the ribbon cable, behavior is inconsistent and the example files do not run. Perhaps the ribbon cable is defective? I read this as a possibility in another post here.

Thanks.

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adafruit_support_rick
 
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Re: 64x32 LED Matrix

Post by adafruit_support_rick »

LEDLED wrote:behavior is inconsistent and the example files do not run
What exactly do you mean by 'the example files do not run'? Can you post some pictures of the behavior?

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

By this I meant you can deduce the intended output from reading the Arduino code, and it does not appear on the LED matrix. For example, Adafruit Industries text.

However before the Arduino is considered, I was wondering can we rule out/in the ribbon cable? Again if the Arduino is disconnected from everything, and the ribbon cable is plugged into the powered matrix, a glitchy light show appears depending on whether the cable is moved or held at different angles. I am wondering if that is expected behavior.

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adafruit_support_rick
 
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Re: 64x32 LED Matrix

Post by adafruit_support_rick »

It certainly sounds like a bad cable.
Please email [email protected] with a link to this thread for a replacement cable

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

Thanks for sending out the new ribbon cable. When I plug this one in, the same kind of glitch-out behavior occurs when there is any kind of movement. If you jiggle the ribbon cable into the right position, then it seems "ok" (at least for a brief testing period). However, the intended application is not necessarily going to be a vibration-free environment. Any thoughts on why this might occur?

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pburgess
 
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Re: 64x32 LED Matrix

Post by pburgess »

Could you post some clear photos of your wiring? Both the Arduino side, and if you can get a get a close-up of the socket on the LED matrix (unplug the ribbon cable), that might help too. Are you using jumper wires between the Arduino and matrix, or have you assembled a proto shield for a more permanent setup?

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

At the moment, the Arduino Mega is completely disconnected from everything. It is unpowered and "un-ribboned".

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

I can post a video of the glitching though. How does that work - link to Youtube?

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pburgess
 
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Re: 64x32 LED Matrix

Post by pburgess »

Sure, that'd be a start.

How was the Mega connected to the ribbon? Shield or jumpers? If jumpers, were they hand-cut, and what gauge?

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

The new ribbon cable has never been connected to the Mega. I opened the Adafruit package and connected it only to the LED matrix. Thanks.

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »


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pburgess
 
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Re: 64x32 LED Matrix

Post by pburgess »

Ah, I see now.

This is normal, actually. There are no pull-up/pull-down resistors on the matrix inputs. With no connection to an Arduino, the inputs are all "floating" -- neither high nor low -- but the wires acting as sort of antennas, picking up whatever electrical interference is convenient, which our bodies excel at providing.

Looks like you have a proto shield set up on the Mega. Plug into that. If it works, great. If not, possible missing or wrong connection, in which case a close-up of the wiring would be helpful.

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

I am at the code portion and running into some snags. I am running the testshapes_32x64 Arduino code supplied with the library. Based on the pins described in the guide, I have changed the pins as follows:
#define CLK 11
#define OE 9
#define LAT 10

#define A A0
#define B A1
#define C A2
#define D A3

Some lines of code execute properly. For example, this:
// fix the screen with green
matrix.fillRect(0, 0, matrix.width(), matrix.height(), matrix.Color333(0, 7, 0));

Some lines work unexpectedly - for example, I wrote the following code which produces an "L" shape instead of a rectangle. The "L" shape has two full lines along the long axis and is a 10x1 line along the border of the short axis:
matrix.fillRect(0, 0, matrix.width(), 10, matrix.Color333(7, 0, 7));


However, everything else does not such as all of the text code and circle code.

I did check through the wiring as I built so is there anything else I might be missing here on the code/setup side? Thanks.

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pburgess
 
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Re: 64x32 LED Matrix

Post by pburgess »

Could you post the complete source to the sketch? I'll try it out on a board here. The pinouts you mention there are the same as the 32x64 example sketch.

Also, could you try the colorwheel_32x32 example, changing the pin numbers to match your setup there? When run, you should see two copies of the color wheel, one of which is a bit distorted (but the one nearest the input header should appear correct). If this doesn't work properly, a photo of the matrix showing the output, as well as a clear shot of your wiring, would be helpful in troubleshooting.

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LEDLED
 
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Re: 64x32 LED Matrix

Post by LEDLED »

OK, here are some photos. They are really big on the forum but if you right click, it can be seen easily with Windows Picture view, etc.
Image
Image

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