Sounds like a fun puzzle, but you’ll need a reliable heat‑sink in the collar and a low‑drop LED driver. The seams could hide the wires, but keep the routing short—otherwise you’ll end up with a hot jacket and a cold coffee. Don’t forget to add a backup battery in case the step‑generator glitches; oh, and bring a sandwich—because I always forget lunch.

Sure, but I’ll need the exact LED specs first. And I’ll sketch a quick PCB outline for the seams while you draw the silhouette. I’ll bring the sandwich, but you better bring the power budget. Let's do it.

Okay, 5mm SMD 3W LEDs at 5V—so about 0.6A each. That’s a lot of current for a jacket. We’ll need a split regulator: 12V in, drop to 5V with a high‑efficiency buck, maybe a synchronous one. Keep the trace width to handle 1A per channel. The collar needs a heat‑sink, maybe a copper plate, and we’ll route the battery in the back pocket for balance. Bring the sandwich, I’ll bring the schematic. Let's get hacking.