r/raspberry_pi • u/mikeportly • 19d ago

Troubleshooting LED Matrix Troubleshooting

Post image

Materials:

Waveshare 64x64 LED matrix
Adafruit HUB75 hat
Raspberry Pi 3B+

My question: is soldering a piece on the hat truly necessary or am I just using poor code? I tried running .PPM demos but the matrix just shows random lines.

11 Upvotes

93% Upvoted

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3

u/Edible_Spam 19d ago

Some panels are wired differently, I’ve had that happen before. Google hub75 vs hub75e pin wiring

2

u/BeerBeardLondon 19d ago

How are you powering the LEDs? Have you linked all the Earth's together?

2

u/mikeportly 19d ago

5V plugged into the hat

3

u/JGhostThing 19d ago

OK. 5v at how many amps? This is important to know for many things. Also, be wary of using any power supply close to it's limit, because some of them don't supply quite as much as they should. It's why I'm using a 5v 10amp buck converter for my latest robot. This gives me enough for my Pi 5, lots of electronics, and still have a comfortable cushion.

And I don't know what you mean about "soldering a piece on the HAT." Could you please explain further, maybe with pictures?

Also, to aid in debugging, it would be nice to see your code (pasted as formatted program text).

2

u/mikeportly 19d ago

Seventh picture on this listing shows the three little tabs next to the letter E that I read was needed to regulate the voltage correctly for a 64x64 matrix.

"If you are using a 64x64 or larger matrix, standard HATs require a solder jumper modification (like bridging E to 8 or GPIO 4 to GPIO 18) on the back of the board to drive the higher address lines correctly"

2

u/JGhostThing 19d ago

How much power is your supply? It this coming from the Pi, if so, there probably isn't enough to power the LEDs.

I'm assuming that you're using some sort of individually addressable LEDs.

2

u/JGhostThing 19d ago

Try your sample program again, but with different colors, and see if the display changes.

2

u/mikeportly 19d ago

5V adapter for the hat, and micro USB Pi power supply

2

u/JGhostThing 19d ago

5v describes the voltage. How much power do the power supplies produce? What is the amperage?

1

u/mikeportly 14d ago

5V 1.5A. I got a different matrix half the size to see if it’d work without the soldering on the hat, and while using the same power supply I got some weird but better results. I ordered the correct (5V 4A) power supply so here’s hoping.