We’ve seen our share of light-up jewelry over the years, but for some reason — probably power — it’s almost always earrings or necklaces. So when we saw [ROBO HUB]’s LED ring, we had to check it out. It involves a bit of behind-the-scenes action in the form of a battery holder that you palm, but the end effect is quite cool.
Essentially, this is a 3D printed ring with SMD LEDs painstakingly soldered together in parallel along a pair of thin copper wires. The ring itself is in two parts: a base, and a cover to diffuse and protect the LEDs. A pair of wires run out from the ring and connect to a printed coin cell holder.
One thing we like about this build is the way that [ROBO HUB] handled the soldering of those tiny LEDs — by binder-clipping the ends of the wires to a piece of protoboard at just the right distance apart. Be sure to check out the build video after the break.
So, is there a way to do this without having to palm a coin cell? Yes, and it involves a tiny capacitor and an inductive charging bracelet.
Source : https://hackaday.com/2023/11/28/led-ring-brings-the-bling/