This Solar-Powered Ear Ring Turns With The Sun

Jewelry making offers many opportunities for the electronics tinkerer, and on these pages we’ve seen some eye-catching creations using LEDs to great effect. They all have the same limitation though, it’s difficult to power something that tiny without a cumbersome battery. In seeking to solve that problem there have been a variety of inventive solutions tried, but they haven’t matched the approach of [Lloyd Konneker] who has turned the whole premise of most electronic jewelry on its head.

Instead of LEDs, the party trick of his earring is an electric motor that makes it spin, and instead of giving out light it takes it in as solar power.  The motor is a pager alert device, the solar cells are repurposed photodiodes, and the power is stored in a capacitor until there is enough to drive the motor, at which point a MOSFET is triggered to do the work. It’s all made possible by a Texas Instruments TPS3839 supply voltage supervisor chip, and it works well enough to turn from time to time in bright sunlight. The prototype uses a conventional PCB, but a better version is in the works with a flexible board.

His write-up should be of interest to anyone with a need to learn about micropower circuits, as it goes into significant detail on their tuning and operation. Last year’s Hackaday Prize had an entire section devoted to energy harvesting which is well worth searching the site for, a typical example was this solar powered microcontroller board.

Light Up Earrings

light up earrings

Unfortunately [ch00f’s] been too busy to write for Hack a Day lately, but he has finished off an awesome little project — Christmas LED earrings!

As with all his projects, there is a brilliant write up that covers everything — even for the stuff that didn’t work. But what we really have to admire about this project in particular is the scale at which he was working. The tiny battery squished in between the two boards? A mere 19mAh. Which is actually enough to power the earrings for a few hours, but is only the size and thickness of a few microSD cards!

The second thing that really popped out at us was the boards themselves, there’s just no room for a programming header! To work around this [ch00f] actually made the PCBs in 3 segments, programmed it, and then cut off the programming header section! If that’s not enough ingenuity, how about this – He also included hall effect sensors on-board to turn them off while charging! Not to mention an intricate wood box to charge them in…

Stick around after the break to see the great demo video, it even has some classy music from the 1930’s which really sets the mood.

Continue reading “Light Up Earrings”