Make 2 outputs act as one continuous strip?

Hello, first post here. I tried to search but could not find a clear answer. I’m planning my first project and will be installing 1200 W2815s around the border of a room. I see in LED settings menu it suggests to use less than 800 LEDs per output. The way I plan to layout, the beginning and end of the strip will be at the same place. I plan to inject power at both ends and see how that looks before considering other options.

Here are my questions:

  • Could I connect the second output to another GPIO at the end of the strip so that I have 600 LEDs on each output for better performance?

  • How should I plan the layout so that the entire strip will behave as one?
    My concern is data flow direction marked on the strip since I would be sending data at the end of the second strip. I’m new to addressable LEDs so not sure if that is just a marking on the strips or if it must be followed. Obviously, I’m trying to avoid running 30m of wire to the middle of the run for the data connection.

  • If I connect second output at the end of the strip, do I need to notch out the data connection in the middle of the strip to separate the outputs and avoid issues?

  • For the second output, would I tick “Reversed (rotated 180°)” so that the strip behaves as one continuous strip for effects? e.g. the first pixel at the “end” of the strip would then be the last?

  • Or should I run 2 independent 600 LED strips and connect power and data from one end to test? Injection at the opposite end will be challenging. I am curious if I can get the desired look without having to inject.

I’m not sure if I’m on the right track or if there is a totally different way to go about this. Any other suggestions or settings that I am missing to accomplish this?

Thanks and appreciate the insight.

That is the normal behaviour of WLED.

You can run them on different pins for data if that would work more efficiently for your setup then do it. I ran a 1200 LED 5meter strip of 240/m WS2812b cob with no issues off one pin. Used a WT32 ETHO1 for it with ethernet though. It even worked smoothly with 13 other ESP32s on a huge Hyperion room build. If running multiple data lines, make sure you arent sending one more than a 10 feet before it desrinations first LED. After you set up the 2 GPIOs in LED preferences on your main screens menu for the device under “segments” column just create a segment of 1200. Even of it involves deleting the segments created. Run the scene you wish it to boot up with everytime and set your brightness. Create a Preset and keep all the things checked. Type in a name. I usually put STARTUP “title name”. Take note of what the number preset this is. probably 1. Go into LED preferences and scroll down to Apply Preset … at boot. Put a 1 in there. Save reboot, hope all goes smoothly.

Thanks for the thorough response. I received all of the materials and laid everything out on the floor to test. It works well and I compared the difference between using one GPIO vs 2. I think I will go with 2 since it’s easy enough to layout and setup in WLED.

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Just one small comment on a statement you made:

… I am curious if I can get the desired look without having to inject…

As others have said, from a data stream/programming POV, it doesn’t matter if you connect 2 pieces of 600 LEDs to 2 different GPIOs or join them end to end as one continuous strip. WLED will show you 1200 continuous addressable LEDs.

There is no issue of “injection” with LED data, the main thing that comes into play is the distance from the data source to the LED it’s driving. For the 1st LED in strip #1 that’s the distance from the ESP/levelshifter to the strip. With 2 strips, you also have to consider the distance from the end of strip #1 and the start of strip #2 (or, alternatively, the distance from the 2nd GPIO).

  • Note strip “direction” only applies to data not power, so you can easily swap the 2nd strip end for end to make the output of strip #1 closer to the input of strip #2.

Either way, you need to watch out for data source to LED distances that get much beyond 3m. Even with a proper levelshifter There’s a real possibility of your data stream getting corrupted.

Getting power to all parts of that 1200 LED setup is a different issue altogether, that’s where the potential need for injection comes in to play.

Thanks. Yeah I tested 4 5m strips connected end to end sending data over 1 GPIO and it worked OK. Then I connected 2 strips together and each group on a separate GPIO. I found the FPS was much better and visually looked better. So I think my plan is to run 2 separate runs (2x5m ea) from the controller on their own GPIOs. I tested with injection front middle and end and looks good enough for a kids room. I used a 12v 10A brick power supply. I have a Meanwell too but for a kids room I feel better about the brick. Even just at the front of each 10m run looks ok. I can always go back and add injections later but for now I think this is good enough.

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Sounds like you have it all planned out. You should set the limiter in LED preferences if your LEDs are capable of higher than your power supply. You almost never go anywhere near to what they are capable of, but it’s best to do so for safety. Sometimes lights will fail and the ESP32 freeze. It sometimes goes bright white and is stuck like that. Im not familiar with ws2815 yet so dont know the power needs of them. It’s recommended to do 80% of The supplies rating. So 8000 mA. I use fuses in everything and have never popped one, but I’ve had an ESP32 smoke when plugged in to micro usb when it was hooked to nothing else. If there is ever a short circuit wires can melt. You’re smart enought to test the lights first so youll be fine.

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I set the limiter to 8A when injecting both ends of a single 20m strip and the same when providing power to one end of two 10m strips. Effects did not seem much dimmer and voltage drop was only noticeable when doing solid colors at max brightness. I even injected in the middle and set to 16A limit and it wasn’t much different when powering it with a supply that could provide the correct power. So I think for a kids room and the limiter set to 8A it will work out just fine. I’m very comfortable working with electronics and soldering. One of my other hobbies is building and flying planes and quadcopters. I build my own batteries as well. Some of which are extremely dangerous :rofl: I am definitely going to fuse all of the runs just for added safety. Thanks for all the input.

Might want to measure the real draw of a live strip with 10-20 LEDs at 100% bright. That will give you a real world value for the max current/LED. If your PS is capable of delivering that and your injection is sufficient, you can disable the ABL or set it to 65000mA.

I’d much rather design the power for my LEDs properly than try and use software to fix a design issue.