When I started this project, I ordered different APA102 strips to determine the pin-out. I decided to go with GND - CLOCK - DATA - GND. The strip fits perfect into a 11 pin FFC connector. Each solder pad on the strip connects to two pins on the FFC, creating a pretty reliable connection.
For this new board I ordered an additional strip, 5 meters, but unfortunately the pin-out is different:
This new strip switched the clock and data line, and are no longer compatible with the boards I designed. So I did some research on the different strips out there.
Adafruit has been selling a so called DotStar LED strips which looks exactly like the top strip in the picture above. DotStar is a brand name from Adafruit, and the datasheet reveals the actual type of LED. Here it gets confusing. While the technical details mention APA102, the actual datasheet is for SK9822. Even worse, they have a note with the following: Strips come with 4 solder points per segment, but the arrangement may vary depending on the supplier, so please check when soldering/powering!
So I found the following link comparing the two different LED's:
So after taking a closer look at the board and strips I have been using so far, I noticed that the LED's on the actual board are SK9822, and the strip is APA102. I have not noticed a difference in performance and they behave well together.
Last week I contacted different suppliers to confirm the pin-out of the solder pads and I am expecting a new strip at the end of this week. Fingers crossed it is compatible, and I can keep this project moving.