Hat/Bonnet - LED Panel Anti-Flicker Mod NOT Working

[Dennis_M]

Hello All,

I can't get the anti-flicker mod to work with the LED panels for the MLB scoreboard. I've soldered the wire between GPIO pin 4 and 18. I added the -pwm flag in the script. I'm not familiar with coding so I did this in the Raspberry Pi GUI. I used the crontab -e and then scrolled down.

When I turn on the scoreboard I get the two lights on the right. I don't know what I did wrong? The wiring I used to solder is 26 AWG and it's silver (not copper wiring). Could that be the issue?

Thanks for your assistance.

[adafruit_support_mike]

Silver is a slightly better conductor than copper (it's the most conductive metal, with copper second and aluminum third). It shouldn't cause problems for anything except your wallet.

Do those two LEDs light if you connect the panel directly to the Matriux Hat (ignoring the other matrices for the sake of testing)?

[Dennis_M]

Hello Mike,

Thank you for the reply! Should I connect the single 64x32 panel to the Matrix Hat? The pic is with everything connected. When I swap out the Hat with NO bridge wire and go back in the script and remove the "-pwm" text everything works fine. The only exception being the damn flickering.

I really don't know how to go into the script thru a shell? I just open the file(s) in the Raspberry PI text editor in the GUI (looks like a Windows 10 knockoff OS) and make changes. I also use the crontab -e command to add the "-pwm" text, save it and shut down the PI.

Sorry for my ignorance, thank you!

[adafruit_support_mike]

If the stuck pixels don't show up when you use the matrices other ways, that rules out a hardware problem in the matrix itself.

The glitches are on the last pixels of the 1st and 17th rows. Those are the last ones to be set before the row-address signals change from 0001 to 0010, and before the LATCH signal pulses. Those should be the only conditions that happen for those two pixels but none of the others.

That probably means a signal timing issue, which will be hard to diagnose without seeing all the signals on an oscilloscope.

Try dropping the -pwm option and using --led-slowdown-gpio instead. From the Matrix Hat tutorial:

--led-slowdown-gpio=(0…n) Sometimes needed to throttle back the speed when using a fast Pi. Default is 1.

For Raspberry Pi 3 use a slowdown of 1 to start (use higher values if image still flickers). For Raspberry Pi 4, use a slowdown of 4. Older Pi models might work with 0, try it.