RGB LED matrix 64x32 8mm pitch (demo shows stretched images)

[Lucistrike]

Hi There,

For work I am doing a project with 45 pcs of 64x32 Matrix panels. I need to scroll text from one side to another. Tried Metro M0 before but didnt work out. Currently I am trying with raspberry Pi 3 model B using a HAT shield.

Steps I followed

1. Setup rasberry with RASBIAN
2. Setup pin default to HAT
3. Used Hzeller demo
4. Tested on a string of 3 panels

The result is the letters are stretched and don't work properly, I am a beginner in programming so coding is not yet my strongest skill.

Tested the code on a single 32x32 panel and this worked fine. Could someone please give me some advice the deadline of my project is getting closer and closer. See the video for attachment (dont mind the upside down setup:(

[hzeller]

Please read the README. The artifacts you see are typically happening with too long cables (keep them as short as possible from the Pi->panel) and/or too high speed, so try to gpio-slowdown option. Make sure to properly power all the panels with thick cabeling and possibly capacitors at the entrance.

Note, if you want to control 45 panels with a single pi and only a single output you have with the Adafruit HAT, you will get a very low refresh rate that will show as flicker. Try lower PWM and time dithering as described in the README to somewhat mitigate.

(Also, don't use the Adafruit HAT in the default modifiation, you should use the PWM hardware mod.)

[Lucistrike]

Hi marstro,

Thanks for your reply and advice for the pi, I want to do it with multiple pi”s and make different lines so this will be ok I suppose.

The odd thing with your theory is when I put an 32x32 same pitch matrix as the first board all the other boards react well. See attachment. Any idea wat I am doing wrong then.

Power supply is direct from a 40A 5v transformator with Adafruit wires

Op wo 30 jan. 2019 om 17:37 schreef Henner Zeller notifications@github.com

Please read the README. The artifacts you see are typically happening with too long cables (keep them as short as possible from the Pi->panel) and/or too high speed, so try to gpio-slowdown option. Make sure to properly power all the panels with thick cabeling and possibly capacitors at the entrance.

Note, if you want to control 45 panels with a single pi and only a single output you have with the Adafruit HAT, you will get a very low refresh rate that will show as flicker. Try lower PWM and time dithering as described in the README to somewhat mitigate.

(Also, don't use the Adafruit HAT in the default modifiation, you should use the PWM hardware mod.)

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[hzeller]

The odd thing with your theory is when I put an 32x32 same pitch matrix as the first board all the other boards react well.

No, this exactly confirms it: you have probably too long cables at the input and the 32x32 panel has better signal conditioning at its input so when it passes it on to the next panel it works; the 64x32 apparently have more trouble dealing with the input. Make sure to have as short as possible IDC cable between the Pi and the first panel.