Pixel Strips in Parallel?

TupeloTechie

Active Member
I'm working on a small project with generic WS2811 RGB 30ppm Pixel Strip. I'm needing around 5-7 strips of varying lengths (6in to 2ft.) One end of each strip, along with all the power/data guts will live in a small flowerpot.

Due to the nature of the prop, clean wiring is essential, and I'd like to not have to run a "daisy chain" data wire from the exposed ends back to the flowerpot.

I don't need (or want) individual control of each strip, so what I'd like to be able to do is gang all the data lines from each strip together (as shown in quick diagram below) so that the first pixel of each tape is controlled as one, and so on, even though some strips will be shorter and therefore not have led 6 or 7, etc.

My question is whether this is even possible with the WS2811 protocol? I've found conflicting info about such parallel wiring on google and thought someone here might have the knowledge.

PixelPlant.png
 
The proper way to do this would be to use a multi-output pixel controller or one controller per strip. Just as with DMX, a high-speed data line usually needs buffering circuitry to split the signal. There is limited distance between the output of the pixel controller and the input of the pixel strip. The distance can be variable due to factors such as type of wire used. If your controller could drive the inputs of all of the strips combined, my guess is that this distance would be greatly reduced.

If you already have the pixel controller and it can handle the total power draw of the strips then you can use trial and error and see what you might get away with. There are such things as "pixel extenders" that use a transmitter and a receiver board. Otherwise, a multi-port pixel controller might be less hassle.
 
Hi Paul, I believe the protocol would work in parallel because the data only moves in one direction, kind of like DMX, but unlike RDM. While it is similar to SPI combined clock and MOSI lines, there's no MISO line.

It's hard to predict how many strips a product can drive without knowing what's inside the box. It could potentially burn out the IC chip or microcontroller that is delivering the signal. I agree with Mac that longer distances will lower how many strips can be hooked up in parallel, and the capacitance (characteristic impedance) of the cable will make a difference.

A gate driver for N-channel MOSFET's should be able to drive a bunch of strips in parallel. It's a little bit of work to set up but can be done with about $10 of parts.

Curious to see your final setup, if you don't mind sharing.
 

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