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Questions on Matrix Portal Power Hookup ...
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Re: Questions on Matrix Portal Power Hookup ...

by eddtrettel on Mon Jan 25, 2021 3:39 am

Regarding flickering when using an LED matrix:

I have a Matrix Portal M4 (PRODUCT ID: 4745) connected to a 64x32 RGB LED Matrix - 3mm pitch
(PRODUCT ID: 2279). I have the matrix connected to the portal via the power cables that came with the ADABOX 016 kit. In other words, the matrix is powered by whatever is doing into the portal USB C jack.

During code development I connect to the portal via my laptop USB. On occasion some code will result in flickering, probably because it's asking a lot of the device in terms of power for certain output.

Leaving the exact same code on the portal, I Eject it from my laptop and connect it to the 5V 2.5A Switching Power Supply with 20AWG MicroUSB Cable (PRODUCT ID: 1995).

The flickering goes away.

Back on the laptop power it flickers.

Something to be aware of. There might be nothing wrong with your matrix or your portal/microcontroller. Just short of power from a laptop.

As some have noted in the above discussions, you need to supply USB C power to the portal, but you could supply a separate 5V high-amp supply to your matrix, using power cables.

BTW, while it may not make a difference, I'm using Circuit Python with the MatrixPortal library.

Cheers,
E.T.

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Mon Jan 25, 2021 11:07 am

You should make a separate thread for you question rather than bury it at the end of another that's reached closure.

But, I agree that it's probably a power issue. Most USB ports can only supply 500mA (USBC ports can probably do more).

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by lovetheants on Mon Mar 22, 2021 12:12 pm

To power the matrix portal, would this work?
https://www.adafruit.com/product/4298

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Mon Mar 22, 2021 3:19 pm

For a 64x32 matrix, a 4A supply is recommended. The Pi4 supply is just 3A.

You could use https://www.adafruit.com/product/1466 with https://www.adafruit.com/product/4536, although that adapter is awkward sticking out. An alternative would be to use https://www.adafruit.com/product/368 and feed power into the 5v & Gnd screw terminals.

That's the official recommendation on the MatrixPortal page. However... I see (as I keep digging) that the ADABOX16 essentials (aka MatrixPortal starter kit) comes with a 2.4A power supply. So, as long as you don't make most of the LEDs bright white at the same time, the 3A supply is probably plenty.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Thu Apr 15, 2021 8:53 am

I hooked up the LED matrix to a 5V 4 amp power supply by following this guide https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/powering?view=all. First, I realized the Matrix Portal does not get power using this method. Is it ok to connect the power supply to the standoffs on the matrix portal that are used to connect the portal power to the LED display and then run the leads to the display from there as well?

Second, when powering the LED matrix (64x32) with the power supply as described in the link and connecting the matrix portal to my computer via USB-C, the LED display works. However there are portions that are jittery or flickering.

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Thu Apr 15, 2021 9:37 am

You can power the MatrixPortal via the standoffs. At the very least you will need the ground connected... maybe that being missing is your flickering issue?

HOWEVER you can't have 5v supplied to the standoff at the same time USB is connected. There's no protection diodes in place to support that.

The safest and least error prone way of powering is to power everything via the USB connector.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Thu Apr 15, 2021 10:27 am

Powering via the USB would be ideal but it seems 4A is not an option right?

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Thu Apr 15, 2021 10:44 am

Not from a computer's USB port, no.

I don't see anything in the shop to adapt to USB-C. Do you really need 4A? Are you planning to run the panel at close to 100% full brightness white?

The Raspberry Pi supply will give you 3A with a USB-C connector.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Thu Apr 15, 2021 10:11 pm

Still having an issue with my LED matrix portal after powering both the matrix portal and the LED panel with 5V 4A. See https://youtu.be/f7eLmbT30so

Anything else I can try?

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Fri Apr 16, 2021 10:07 am

Hmmm. Do you see the same behavior at a slower scroll rate? Does a static display work?

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Fri Apr 16, 2021 4:32 pm

Still seeing abnormal behavior with a static image. Note the top left of the pipe picture. photos herehttps://photos.app.goo.gl/NfRsd5FL3K8CmSK19

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Fri Apr 16, 2021 5:56 pm

That corner weirdness with the pipe graphic... it is static or glitchy/random?

Also, what is your 4A supply?

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Mon Apr 19, 2021 9:41 am

dastels wrote:That corner weirdness with the pipe graphic... it is static or glitchy/random?

Also, what is your 4A supply?

Dave


Glitchy and random. The power supply is this 5V 4A https://www.adafruit.com/product/1466

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Mon Apr 19, 2021 10:13 am

OK, that's a good power supply... shouldn't be noisy.

Is the weirdness always toward that corner?

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by keenest on Mon Apr 19, 2021 8:57 pm

Hmmm yes I believe so. At least in all of the tests I have run. Indicative of a problem with the Matrix Portal or the LED matrix?

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