This is a head scratcher for me. I got 50m of fairly lights to put up for Christmas. My first thought was cut a bunch of strips to put up on the posts on the front porch. Right now I just have two 43 led strips wired in parallel. When I ran through some effects I noticed the two strips are not in sync. One is slightly behind the other. They are 12v and hooked up to a single power and data output on a DigQuad. I defined the main segment to be groups of 3 LEDs so it is easier to see. A picture is worth a thousand words so I have attached a video. Any thoughts on why this might be happening?
Yes I have double and triple checked they are the same length.
Wired in parallel means that the power from both strips are connected together, the ground from both strips are connected together and the data from both strips are connected together. Essentially two strips wired as if they are one. I drew only a single data line for each strip but they have a primary and backup on each strip so just imaging there are two data lines coming from each strip and all four data wires going into the strips are connected together.
The only thing I can think of is that one of the 2 strips is managing the “backup” data line slightly different than the other.
For normal operation, strips with a BIn should be tied to ground at the start of each strip.
After the 1st LED, the BIn line is handled by the strips internal wiring so you don’t need to worry about it.
Try grounding both BIn’s and see if that makes any difference.
BTW, there’s no reason not to connect the 2nd strips’ DIn to another GPIO on the DigQuad.
You configure WLED to have another 43 LED strip on the 2nd GPIO.
WLED shows that as one long strip of 86 LEDs.
If you want both to show the same thing at the same time, you create a Segment that Groups 2 LEDs with a Spacing of 42.
That means when LED 0 (start of the 1st strip) lights, LED 43 (start of the 2nd strip) lights the same way. Anything you do to that Segment (colours/brightness/effects, etc) is matched in both strips.
The advantage over a simple wiring replication is the option to do something other than a simple mirror - like have a sweep effect run from Left->Right on one strip and Right->Left on the other (or a million other possibilities).
why dont you just use a levelshifter and make all inputs to the MCU pin and the outputs to the different stripes
i personly use this for the props that are Arrayed or multiplied as they got the same sequence
