After a year and a half, I have finally gotten around to posting about my solar necklaces project. The first version was a lightsaber-inspired necklace. Using solar power to charge a supercapacitor, it also uses the solar panel to sense when it is dark, and turn on and glow.
The second version attempted to overcome the issues with the lightsaber necklace (namely that it is too large for daily use, and that it is too difficult to assemble with reasonable quality) in a more elegant (albeit less nerdy cool) moissanite necklace. The goal here was to use a small microcontroller, switching between different LEDs behind the stone to give it the same “sparkle” (scintillation) in the dark that it might have in the sun.
Both necklace versions only glow for ~30 minutes to ~3 hours (to a dim light there at the end) but can charge and discharge ‘indefinitely’ without intervention, unlike a battery powered version.
I have more details on hackaday and GitHub, if you want more project build details:
https://hackaday.io/project/205529-solar-powered-necklaces/details
https://github.com/winedarksea/solar-necklace-attiny
See them both in action in these GIFs:
