WS2815 + SK9822 Expander

Hey guys,

I’m combining SK9822 LEDs with WS2815 LEDs using the pro expander board. I have 120 SK9822 connected to channel 0, another 120 to channel 1, and 284 WS2815 set to channel 7.

I have the pixel count set at channel 0:0, channel 1: 120, and channel7: 240.

On the set of WS2815 that are under mount here (not the vertical LEDs), the first few pixels (bottom left) eventually get stuck on a solid color. This only happens when using the expander board, if I drive WS2815 just from the PB, this never occurs.


Hi @ElectrikRaver,
My guess is that they are overheating. The first part of a strip carries the most current, and thus will heat up the most. Many WS2815 strips get quite warm. Installing them can make things worse as it tends to limit air flow.

I would try dropping the brightness, and seeing if the reduced power draw helps. If you can, add additional power injection along the strip and make sure things don’t get too hot!

@wizard I don’t think it’s a heat issue, there’s no noticeable differences in temperature at least to the touch on these.

I think it has to do with the data connection, and I might have just figured it out. The only thing that is unclear to me with the WS2815 pcb and connecting to pixelblaze is what to do with the backup data out of the expander/pixelblaze, should data and backup both be connected to data terminal?

Thanks as always!

Hi @ElectrikRaver,

The WS2815 datasheet recommends connecting the first backup data input to GND.

Pixelblaze and the Expanders do not have an output for backup data. The other output is for clock, which is only used for APA102 type LEDs. On the Output Expander Pro, channels 6 and 7 are routed to these clock signals.