Wearable electronics can be both fun and fashionable. However, there are certain challenges involved in neatly integrating electronic components in a way that is both functional and comfortable for the wearer. In this vein, [Jiri Praus] has managed to create some glowing earrings that are remarkably simple to boot.
The earrings start out with brass rod, bent with pliers and soldered at the ends. By following a paper template, it’s possible to get neat and accurate bends by hand, which is necessary to make a matching pair. Through careful design, the brass rods are soldered to the LEDs, and more rod is then used to create an integrated holder for a coin cell battery, which powers the lights.
Thanks to [Jiri]’s smart designs — which we’ve featured before in the form of a blooming wireframe tulip — no wires are needed. The brass rods which make up the body of the jewelry also act as the conductors to pass current to the LEDs. The internal resistance of the coin cell battery also eliminates the need for an in-line resistor. In combination, this serves to create a simple and attractive finished product that should shine for several hours.
We’ve seen other LED earring designs before, too. There are plenty of ways to experiment with glowing jewelry, and if you’ve done something novel, be sure to let us know.
I love the look of them. I have two thoughts:
CR batteries are not rechargeable. There are some in the same sizes, but I didn’t see it mentioned in the instructable. Not really environmentally friendly otherwise to use a coin cell for a few hours of light.
I find those SMD LEDs mechanically weak to be used in such arrangement. Some kind of glued reinforcement on the back would be useful in a worn piece. A thread of glass fiber with a drop of epoxy, maybe?
I’m sure the coin cell could be swapped for a rechargable version (LIR2032 etc.), perhaps with a matching jewellery holder-slash-charger to keep with the theme?
I’m surprised that those paralleled LEDs light up evenly.
No current limiting resistors used for the leds?
That’s waiting for them to fail one after the other.
The current won’t spread evenly through the leds because of small differences in resistance, so one led wil take most of the current, burns, and the current will flow through the new “low resistance” led….
LEDs are safe to be drived with CR batteries, because the batteries’ internal resistance is too high. There are many cheap LED accesories having just one or two CR and an LED. I’m not sure about evenness in current flow though..
A good Cr2032 (no cheap unbranded) can deliver peaks of 30mA. This is enough to reduce the livetime of the led significantly.
Not really a problem.
1.) It can deliver PEAKs up to 30mA, not continous current, at least not very long. There are even LED torches with 1 LED and 2 CR2032 in series. Although the LEDs are a little overdriven in that case.
2.)The current is divided between several LEDs. Even if the current distribution is not perfect, this will be OK.
3.)Mostly cheap cells are used
4. The overall operating hours of such jewellery are normally well below 100 anyway,