Driving matrix's

Hey all!
I have a few questions to help me get up and running and need some confirmation I am on the right path. I have been reading everything I can find and I think I know what I need but please correct and offer solutions if I am confused.

I am working on a project where I will drive 5 of these panels daisy chained together: https://www.aliexpress.us/item/2251832516511550.html?spm=a2g0o.detail.0.0.30dfjhzcjhzcSp&mp=1&gatewayAdapt=glo2usa

I am going to mount them on some type of framed situation on the wall to be a visualizer for my stereo. I will finalize the frame and finish once i have all the materials in front of me and can minimize or work them into the display.

Here is my bill of materials to make this work and be sound reactive.
5 LED panels
1 Pixelblaze V3
1 sound expansion board
Power supply for the PB. - need recommendations for this the smaller the better
Power supply for the panels -need recommendations for this the smaller the better
My computer and phone for programming and adjusting

Do I have the right idea here?
Am I missing anything?
What power supplies would you recommend that are small?

Thank you all in advance for the help I am trying to get the basics down for this project.


You’re on the right path for sure. The PixelBlaze draws very little power relative to that many LEDs, and you can just back-power it from the same wiring you’re using for the LEDs themselves – it doesn’t need a separate power source. (If you did want to power it separately, just remember to have a common ground wire, and you can drive the PixelBlaze off MicroUSB).

For power, the MAXIMUM amount of power a LED can draw is 50-60 mA at 5v. You have 980 LEDs, so the most conservative amount of power is a 50-60 amp power supply, which is a lot. However, that’s 100% white, 100% lit up, 100% brightness, which is VERY white and VERY bright. If you’re willing to decrease the max brightness, avoid full white all pixels on patterns, you can drop that by a sizable amount, and I would recommend doing so. See Overview | Sipping Power With NeoPixels | Adafruit Learning System for more details. Something like this – https://www.amazon.com/BTF-LIGHTING-Aluminum-WS2812B-LED8806-Modules/dp/B01D8FLYW6 at 30a or this https://www.amazon.com/BTF-LIGHTING-Aluminum-WS2812B-LED8806-Modules/dp/B01D8FLZV6 at 60a-- BFT LIGHTING is a pretty reliable high quality vendor (also available on Aliexpress cheaper / slower).

You’ll want to inject power at several points to avoid voltage drop – in other words, this will require a little bit of soldering and wiring. I’d probably just inject power every panel, because those panels or other similar ones make it easy to do so. (look at the pads on the back of them).

I personally would include in-line fuses for something I’m putting with high power draw in my house, because… safety stops your house from burning down. Those can be really simple – PixelBlaze’s own store sells a version. Inline Cylindrical Fuse – ElectroMage Shop – those are rated 10a / 5v, which means if you’re injecting power on each board and running the power through them you should be safe.

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I’ll note that you an probably tune your system (using the tips linked above) to get away with a 10a power supply if you’re really space and setup constrained – but you should still use in-line fuses, inject power, and test it out very carefully and probably not enclose it – in which case you can use something like https://www.amazon.com/BTF-LIGHTING-Plastic-Adapter-Transformer-WS2812B/dp/B01D8FM71S . If I was doing it myself, that’s what I would do – since I am I recommending this to an internet stranger, I’d tell you to go with a 50a supply for added safety.

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How does this look?

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I’m not the best power and wiring person in this forum, by a long short, but at a high level this looks correct and good to go.

By the way, your diagram reminded me to look at the panels you’re using – You CAN use these panels (that have a separate clock line), but you don’t NEED to for the type of visualizations you’re going to do, and it will be cheaper and simpler to use WS2812B panels that don’t have a separate clock line if you can find them at 20mm pitch – they’re more commonly sold at a 10mm pitch.

https://www.aliexpress.us/item/2251801852582837.html is an example at 10mm pitch, and a FRACTION the price. I bet they exist at 20mm pitch, but will take some searching through bad product listings.

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What’s the downside of not having a clock line? Low frame rate? what other trade offs?

Also other questions that are hanging me up.
What gauge wire should I use for all this extra wiring?
What do I search for connectors to hook the PB up to the powersupply?
What splitter should I use to split the power?

There’s not really any downsides to WS2812B for installations like this – it matters for things like persistence of vision effects; for a first time project like this one, it doesn’t really matter.

Wire gauge – make the power management assumptions you want, and Google “led wire gauge chart” based on those assumptions. My guess is the answer is going to be 16 or 18 gauge wire as the recommended for power and ground, maybe slightly thicker from the power to the splitter. (You can use 22 gauge for the data / clock lines).

The PixelBlaze comes with a simple screw terminal you solder on, and then you just… screw the power and ground wires down onto it. No added parts needed. You actually don’t need to run power to it separately like in your diagram if you don’t want to; instead you can run power between it and Panel 1 (remember, electricity will flow both directions).

Splitting the power – Lots of ways to do it, I’d use a “power bus bar” (search that on Amazon).

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This sounds like an excellent project! I think you are going to have a lot of fun and learn many new skills.
You have chosen a good controller for your visualizers, PixelBlaze is the best and just keeps on getting better.
Regarding your choice of LED type, I think @ZacharyRD is correct when he recommends WS2812B LEDs. They are approximately one third the cost of SK9822’s and perform their required tasks very well. If money is no object or if you will be filming your visualizers, spend the money and go for the SK9822’s. I’ve read they are very smooth, offer more colour options at lower light levels and are also flicker-free at most shutter speeds.
I’ve built a couple of visualizers similar to those you are planning, and have found diffusion is very important. It is very hard for our eyes to look at bare or poorly diffused LEDs. One of the best diffusion materials for thin wall-hung enclosures is black LED acrylic. Here is a link to the post where I first saw how awesome this material is at diffusing LEDs.
8x8 SK9822 Matrix Through Black LED Acrylic at 17mm
Also, here is a link to the build guide I made for my visualizers, I hope it is somewhat helpful.
Build Guide for Party-in-a-Box
Have fun building your project!

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Thank you for posting this. This is not my first rodeo in making things by any stretch of the imagination but I have no idea why it failed to occur to me what I am looking for is a build guide. I am going to dig in to what you post and then surface for questions about fiddely things like connectors etc… Thank you!!

I changed my design, to follow something similar to the party in a box build log. I now have a matrix of 21 rows of 27 LEDs that are arranged in a zigzag pattern.

My question is I showed it to a buddy of mine and he says I should run power on the sides instead of just relying on the power flowing through the zigzag. I’m looking for understanding and opinions on what I should do so I can move forward. Any general guidelines would be great too, for example "you need to inject power of you ever have more than X number of LEDs. "

Thanks in advance !!

How does this new wiring diagram look?

I like it. The bus bar is a good idea.
I just ran jumpers on my larger boards from row 1 to row 6 to row 11 and so on, right along the outside edge, but I like the bus bar better. :+1:
You could have up to 6.5A on each 4 row section (if you were building highway signs!), but for a display like this it’s probably going to be around 2A.
The math is easy, 108 LEDs x 0.3W = 32.4W, or 6.5A for each 4 row section at 100% power, white light. I think I’ve done that once, during testing with an ammeter in the circuit. In everyday use most of my displays run at 40% in the power setting, and app. 1/3 power on the slider in the UI.
However, you might as well build it to code, because we can all do silly things occasionally, and no one likes blowing up their own projects!

Hey everyone!

I just finished my first build and I couldn’t be happier with the final product. It looks polished like its store bought. Works beautifully with a 10 amp power brick limited to 30%.

Here is a link to build photos: https://imgur.com/gallery/vNIDM2I

Here are some links to it in action.





Awesome build!!
The pixelation has a “machine” or “electronic” look that goes well with your choice of music. With my visualizers I used app. 19mm between diode and diffuser for a smooth, flowing, lava lamp-look. However, I also like the vibe of the pixelated look that you have created.
The cardboard and aluminum channel frame you used is brilliant, probably less than half the weight of my wooden boxes.
I think five of these are going to be very impressive! :goat:!