Circuit schema 2 ways WS2812 connect with 1 PCB layout

[Stealthrt]

Hey all I am having a difficult time trying to figure out how to go about the following:

I am wanting to just make 1 pcb but I am using WS2812B LEDs and therefore needs to be in the correct direction. I am looking to panelize the PCB and don’t really want to create 2 different PCBs.

My current schema of this is below which I do not think is correct:

Basically If i start from the left side then it would be:

IN->OUT->IN->OUT->IN->OUT->To the next PCB

And vis-versa:

To the next PCB<-OUT<-IN<-OUT<-IN<-OUT<-IN from previous PCB

Then back:

IN from previous PCB->OUT->IN->OUT->IN->OUT->To the next PCB

Visually this would look like this:

So I am not sure what the correct way to wire them up in the schema that would function the way I am wanting to do it?

So to recap - just want to be able to use 1 PCB that will do both left and right connections for the WS2812B LEDs.

[retiredfeline]

Simplest way really is to make two designs. You can get bargain prices for quantities starting from 5 that you’ll probably get charged more for panelising.

Otheriwse design the PCBs to be rotated 180° for R-L usage.

[paulvdh]

I assume that each green rectanle is a PCB with (in the example) 3 LED’s in series.
There is no need at all to make the PCB’s any different from each other. If the signal goes from right to left instead of from left to right, simply turn around the whole PCB. If you make the PCB itself symmetrical you won’t see the difference. (Except that the RGB LED’s in the WS2812 are not symmetrical either, but they are very small and very close together.)

Or just do it the simple way:

1. Buy pre-made LED strips.
2. Cut the long (5m or so) strip into pieces.
3. Orient the pieces as shown in your drawing.
4. Wire up the sections.

You can buy LED strips with these LED’s in different pitches and length.

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And if you really want to make it difficult for yourself and reverse the data direction while keeping the LED’s upright, then add “solder jumpers” to the data lines, so a data line can be used for data in either direction. You don’t have to double up the wiring, just reverse the data connections to the IC’s.

[Stealthrt]

After a few I think I managed to draw up the schematic correctly in order to use the same PCB in its normal orientation without the need to flip it upside down or have a 2nd pcb altogether.

This look good?

[retiredfeline]

Your parts probably fit on one side. You could probably have different circuits on the two sides then you could choose the side you want to populate and not have to solder jumpers. I don’t know how that would work if you order assembly also.

[Stealthrt]

Yeah I plan on ordering assembly as well as I am not skilled enough to solder those tiny components. And also the fact that I will need 75 PCBs of these.

[paulvdh]

What is wrong (in your mind) with simply turning the PCB itself around?

[Stealthrt]

Because of this:

[paulvdh]

My own preference would be to use a single wire between each of the two LED’s, and then have a 3-way jumper on each end of the wire, so the same wire is used for each data direction. This does require more solder jumpers, but it avoids the long loose wire ends. I am not sure whether long loose wire ends can cause trouble with reflections and noise pickup for the LED’s in this particular application.

[Stealthrt]

I re-measured the item the LEDs will be going on and came out with a PCB that looks the same either right-side up or flipped.

[retiredfeline]

Another thing to think about: How do you plan to get them panelised? V-cuts are not recommended when the parts are mounted close to the cuts so the cuts have to be done before assembly happens. So you’ll have to get them do the panelisation, and you pay for it. It’s not clear how that cost will compare with just ordering non-panelised boards. Have you contacted your chosen fab to ask about your design?

[Stealthrt]

No i have not but I plan on using JLCPCB to do the PCB and the assembly.

[retiredfeline]

Well talk to them then.

[paulvdh]

There may also be a minimum with between V-grooves and other restrictions. Once you start designing some object that has to be manufacturable in a highly automated factory, you have to put up with a whole bunch of restrictions. Seemingly small changes can make your product a lot more expensive.