Problems getting signal to one 16x16 ws2812b matrix

Hey all,

I set up a pixelblaze 3 initially with the 8x8 smaller panel that was also for sale on the site and it worked fine.

I’ve got a larger 16x16 ws2812 panel I bought some time ago and I’ve wired it up to receive power on its own from a 5 volt 10 amp power supply and then connected the pixelblaze, running on its own usb power, with just the data cable. This lights the panel, but not all pixels and absolutely not with a pattern. I redid all the wiring and even desoldered the built in plug on the larger matrix to just solder in the data cable but I cannot seem to get it to react.

It does do some weird stuff if you inadvertently connect the data wire to voltage or ground with a multimeter, and I was able to get as far as having all the pixels light, so I believe they are working, but I am not sure what I’m doing wrong. Is enough power getting to the panel from the data wire? Should I have the pixelblaze hooked up to a common ground with the external power even though I’m not using it to power the pixelblaze?

Thanks in advance!

You must also connect GND (negative) between them. All electrical signals or power work in circuits - there must be a return path for the electrons to do their thing.

Oh ok yeah that worked perfectly.

Makes sense, I just wasn’t thinking about it because I was powering these two separately.

Thank you!

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