I want to install an addressable strip, for instance WS2814 under every step of my staircase. Cabling can only be on one side. How can I wire it? Do I need to run cable back from the other end of every step? Or is there a way to wire every step’s led strip from “start”?
There’s a few possibilities depending on the number of steps and the width of the steps.
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Add a simple “return data” line in parallel with the string so you can get the outgoing data from one step to feed the input of the next.
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If the steps are too wide (more than 2m), you may need to use a TxRx with a pair of wires to reliable send the data between steps.
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If you have few enough steps (8 (?) or less) you could use different GPIOs to feed each step.
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You could use multiple ESP’s to give you enough GPIOs to drive all your steps.
Some more details about the dimensions of your setup and what you hope to achieve would be helpful.
Thanks for these pointers.
U shaped stair filling a stairwell.
19 steps (it got modified during building process 
Leds are ca 90cm per step.
Cable entry from another room in the middle, I marked with an arrow. Can install anything on the other side of the wall (a boiler room). Cables can be run hidden to the steps along the outer perimeter along the wall.
The stair builder wanted to use basic strips, because he is not familiar with anything else. But i would much rather install adressable.
That sounds easier to do, but…
Are there some universal recommendations on the max length of it? Can it be ~1m?
A return line of 1m is probably fine.
I’m guessing this is a build “in progress”? One other option I didn’t mention, as I thought this was a fully completed stairwell - you could reverse the data direction of every other strip.
That puts the end of one strip closer to the start of the next. For eg. if data feeds into the central bannister end of Step 11, you reverse the direction of Step 12 so its data starts at the wall side and can be connected easily to the output of 12. Step 13 reverses again so the data connection from 12 is at the bannister again. This tends to minimize the length of data connections.
It also might make more sense to split your data into 2 sections, one to the left and right of the central data supply. I would feed data in on “Step 10” where it meets the wall, and the 2nd data feed to “Step 11” where it meets the bannister. This needs 2 GPIOs from your ESP board (definitely go for and ESP32 here).
That gives you a rgt-hand segment (Steps 11-17) and lft-hand (Steps 1-10). The display of individual steps and their desired order can be easily handled in the WLED software. Ledmaps and segments are designed to allow control of these scenarios.
If you are in the middle of construction, it might be worth while to consider some kind of small wiring channel on the underside of the steps against the outside walls (and perhaps the centre?) This will allow easier access to wiring for power and data and may make it easier to route the central power to both sides.
Thank you for thinking along.
The stairs themselves are ready. Because of the visual impact I can only run the cable along the outer perimeter (between the steps and the wall) - hence the original question. There is a wiring channel along the outer wall that remains hidden. As no cable can be run on the other end (bannister side), reversing will not be a viable option.
Splitting from the “feed in” point in the middle between 2 GPIOs is probably a good idea. I have used it for other long runs in the house and it has worked brilliantly.
I guess I will start from a bench test with some segments and 1m data lines between them and work from there.
You should be fine with 1m data runs.
I’d suggest you pick some lighter wire for those runs, preferably a pair that includes a ground from the data “source” end.
You may be fine with a simple single solid core strand (22AWG or lighter), but including a dedicated ground line is easy insurance to maintaining the data stream. You might be able to find something light and tiny like the old 2 wire telephone extender cables that will work well (just cut off the connectors).
where can we report spam here?
The “triple-dots” has a Flag as a problem option.
I flagged one of my earlier messages that was hit by that same user.
I strongly suspect they’ve been noted as a problem.
I find, the mods around here are very good at cutting these guys off (Thanks Guys!)