Flickering 64x32 LED RGB Matrix Using Shield for Arduino

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quintb
 
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Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by quintb »

I am driving a 64x32 LED RGB Matrix using the Adafruit RGB Matrix Shield for Arduino (PID#2601) and a Metro M4 Express. I bought the 5V-4amp power supply(PID#1466), and have it wired directly to the LED matrix, and then have power splitting off to a micro USB connector to power the Metro. I tried the sample RGB matrix program from the Adafruit library, and there are random pixels that flicker on the matrix. Whenever I touch the ribbon cable connecting the shield to the LED matrix the flickering significantly increases (see attached picture). I can get the screen to look just fine when I use a code that I made from the sample program, but after a few minutes, some pixels start to flicker again.

I read the post about a similar problem with a matrix driven by a Raspberry Pi that had to do with a timing issue, and I was wondering if that is my problem, or if I need a shielded ribbon cable or something of the sort.
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Re: Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by adafruit_support_carter »

Whenever I touch the ribbon cable connecting the shield to the LED matrix the flickering significantly increases (see attached picture).
This makes it sound more like a hardware issue with the wiring connection in the ribbon cable.

For the program you say works for a little while - is it the library example or your modified version?

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quintb
 
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Re: Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by quintb »

It's a modified version. I get the same issue right when the text appears on the test code though (IMG_2363: notice extra lines around the "I" in industries and the distorted pixels on the top row).

I didn't know if it was code related because as I let the display sit (not touching any hardware), the issue gets worse (IMG_2364: the static picture doesn't show the multiple pixels flickering). If it is hardware related, I checked all my solder connections and other connections to make sure everything was tight and good. Are there better quality ribbon cables I could purchase? Does there need to be shielding somewhere?
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Re: Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by adafruit2 »

hmm! ok lets start - did you try enabling or disable the Cache in the tools menu?

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quintb
 
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Re: Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by quintb »

I did not. However...

I found another 5V power supply I had and used it to power the system and the display was just fine. I then hooked up a variable DC power supply and found that as the supply voltage increases past 5.2V, the flickering/distortion problem gets worse. So... the power supply I was using was giving to much voltage to the LED matrix since I had it directly wired to the power input. To solve my problem I either need to pass the power supply through a voltage regulator before it goes to the LED matrix, or just get a better AC/DC power supply that produces a voltage closer to the nominal 5V.

Thanks for going along with me on this troubleshooting adventure. Hopefully our findings can help others!

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Re: Flickering 64x32 LED RGB Matrix Using Shield for Arduino

Post by adafruit2 »

oh yeah, the metro m4 is 3.3v logic! well, good find :)

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