Sewn silk stole + side-glow fiber optics + warm-white LEDs. I made a total of seven stoles as part of a festival group costuming event. Completed late summer 2019.
Use of the 5mm round LED package was to facilitate connection to the thick optical fiber. Sourcing a high-brightness warm-white 5mm LED was actually pretty challenging!
I decided to learn KiCAD PCB design for this project, and made a tiny LED driver + LiPo battery management board. OSHpark was used for PCB fabrication and I hand-assembled each board. Most of the components are 0603 and SOT-23-5/6.
I ran into a problem with the battery charge IC overheating under load -- the SOT23-6 didn't have enough thermal contact with the ground plane, and I wouldn't have been able to order a new batch of boards before deadline. Fortunately, I was able to retrofit a fix by using some thermal epoxy to attach a miniature aluminum heatsink to the chip.