LED Matrix only lighting every other row

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epistemolojazz
 
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LED Matrix only lighting every other row

Post by epistemolojazz »

Having a problem with a LED 64x32 matrix, with RGB Matrix bonnet. Here is my setup:
  • Raspberry Pi 3B
  • Raspbian GNU/Linux 11 bullseye
  • This bonnet
  • This LED matrix
  • 5.25v 2.5a main power supply
  • 5v 4a supplemental power supply


After following the installation instructions and running the demo:

Code: Select all

sudo ./demo -D 0 --led-rows=32 --led-cols=64
it produces something like this:

Image

(if the image embed doesn't work, link to the image here)

Reading similar stories online and thinking my bonnet was bad, I replaced the bonnet, and reinstalled the support software, but I am still getting the same result. Every demo otherwise seems to work, and I've run through as many of the setting options as I can find, but nothing improves on the command line above. Wondering if this is a defect in the matrix itself, or a software issue, or a config issue, or what.

please help!

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mikeysklar
 
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Re: LED Matrix only lighting every other row

Post by mikeysklar »

I have to use these arguments with my Pi 3B+ and the 64x32 panel.

Code: Select all

--led-cols=64  --led-slowdown-gpio=4
You didn’t mention if you were using the quality jumper or not. If you have not manually soldered it onto the bonnet make sure your installation was for convenience mode.

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epistemolojazz
 
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Re: LED Matrix only lighting every other row

Post by epistemolojazz »

No quality jumper, and I did install for convenience mode. I've tried the

Code: Select all

--led-slowdown-gpio
option on every setting. I am beginning to think the matrix itself is bad somehow. I noticed some other issues with the display... the red leds don't light below halfway down, and some more lines started behaving strangely after I made this post.

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mikeysklar
 
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Re: LED Matrix only lighting every other row

Post by mikeysklar »

This could be a connection issue if things were running and now getting unstable.

With the led-slowdown-gpio I specifically had to pass the '4' parameter with my Pi 3B+ to get smooth performance.

Code: Select all

--led-slowdown-gpio=4
Can you post a photo of your setup? Maybe the alignment of the Bonnet to Pi connection has been compromised?


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mikeysklar
 
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Re: LED Matrix only lighting every other row

Post by mikeysklar »

Thank you for these images. The embedded ones did not work, but the links to dropbox were of very high quality.

The standoffs you are using are the first thing that should be removed for troubleshooting. I can see from the side and vertical views the pins are getting very little contact with the bonnet header.

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epistemolojazz
 
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Re: LED Matrix only lighting every other row

Post by epistemolojazz »

Do you have another recommendation for how to secure the bonnet? I found that without the standoffs, it tends to fall over

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mikeysklar
 
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Re: LED Matrix only lighting every other row

Post by mikeysklar »

You can use shorter standoffs so the board seats closer, but has some support.

I used craft foam sheets as a shim on mine to help keep the bonnet level.

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epistemolojazz
 
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Re: LED Matrix only lighting every other row

Post by epistemolojazz »

Apparently I needed to push the bonnet down further than I thought to make a well-seated connection. Removing the standoffs and pushing it down further seems to have addressed my issues. Thank you!

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mikeysklar
 
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Re: LED Matrix only lighting every other row

Post by mikeysklar »

Cool, glad it was just a matter of seating the board.

If you need to DIY some short standoffs try cutting a small amount of 3mm ID polytubing.

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