Taser Ring Is Scary Jewelry You Shouldn’t Build

January 16, 2025 by Lewin Day 38 Comments

Officially, the term “taser” refers to a particular brand of projectile-firing electric stun gun. However, the word is also colloquially used to refer to just about any device intended for delivering electric shocks to an adversary. The taser ring from [Penguin DIY] definitely fits that description, though we’d strictly advise you not to consider building this at home.

The build is a hacky one. An arc generator circuit was pulled out from a jet cigarette lighter, and reconfigured to fit in a small ring-based form factor. It was hooked up with a power switch and a small bank of 30 mAh lithium polymer cell for power, and a compact USB-C charger board was installed to keep the batteries juiced. The electronics were then delicately assembled into a ring-shaped mold, which was injected with resin to produce the final ring. Once cast, a pair of small metal electrodes were installed on the outside. Activating the taser function is as simple as squeezing the ring—easy to do just by making a fist.

We’ve seen projects like these before; our advice is usually to avoid them unless you really know what you’re doing. Whether you end up shocking someone else or accidentally shocking yourself, the results tend to be bad. The latter seems particularly easy to do if you’re wearing this thing on your finger. Given it’s a ring, don’t expect to be able to pull it off in a hurry, either. It’s hard to see how that ends well.

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Fluid Simulation Pendant Teaches Lessons In Miniaturization

January 13, 2025 by Dan Maloney 6 Comments

Some projects seem to take on a life of their own. You get an idea, design and prototype it, finally build the thing and — it’s good, but it’s not quite right. Back to the drawing board, version 2, still not perfect, lather, rinse, repeat. Pretty soon you look around to discover that you’ve built ten of them. Oops.

That seems to be the arc followed by [mitxela] with this very cool fluid simulation pendant. The idea is simple enough; create a piece of jewelry with a matrix of tiny LEDs that act like the pendant is full of liquid, sloshing about with the slightest movement. In practice, though, this project was filled with challenges. Surprisingly, [mitxela] doesn’t seem to number getting a fluid dynamics simulation running on a microcontroller among those problems, at least not to a great degree. Rather, the LED matrix seemed to cause the most problems, both in terms of laying it out on the 25-mm diameter PCB and how to address the LEDs with relatively limited GPIO on the STM32 microcontroller. The solution to both was diagonal charlieplexing, which reduces the number of vias needed for the 216-LED matrix and allows the 0402 to be densely packed, along with providing some tolerance for solder bridging.

And then there’s the metalworking heroics, which no [mitxela] project would be complete without. This seems to be where a lot of the revisions come from, as the gold-plated brass case kept not quite living up to expectations. The final version is a brass cup containing the LiR2450 rechargeable battery, a magnetic charging connector, and the main PCB, all sealed by a watch crystal. The fluid simulation is quite realistic and very responsive to the pendant’s position. The video below shows it in action along with a summary of the build.

If you want to catch up on [mitxela]’s back catalog of miniaturized builds, start with his amazing industrial ear adornments or these tiny matrix earrings. We’re also fond of his incredible shrinking MIDI builds. Continue reading “Fluid Simulation Pendant Teaches Lessons In Miniaturization” →

LED Matrix Earrings Show Off SMD Skills

February 21, 2024 by Dan Maloney 12 Comments

We’ll be honest with you: we’re not sure if the use of “LED stud” in [mitxela]’s new project refers to the incomprehensibly tiny LED matrix earrings he made, or to himself for attempting the build. We’re leaning toward the latter, but both seem equally likely.

This build is sort of a mash-up of two recent [mitxela] projects — his LED industrial piercing, which contributes the concept of light-up jewelry in general as well as the power supply and enclosure, and his tiny volumetric persistence-of-vision display, which inspired the (greatly downsized) LED matrix. The matrix is the star of the show, coming in at only 9 mm in diameter and adorned with 0201 LEDs, 52 in total on a 1 mm pitch. Rather than incur the budget-busting expense of a high-density PCB with many layers and lots of blind vias, [mitexla] came up with a clever workaround: two separate boards, one for the LEDs and one for everything else. The boards were soldered together first and then populated with the LEDs (via a pick-and-place machine, mercifully) and the CH32V003 microcontroller before being wired to the power source and set in the stud.

Even though most of us will probably never attempt a build on this scale, there are still quite a few clever hacks on display here. Our favorite is the micro-soldering iron [mitxela] whipped up to repair one LED that went missing from the array. He simply wrapped a length of 21-gauge solid copper wire around his iron’s tip and shaped a tiny chisel point into it with a file. We’ll be keeping that one in mind for the future.

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Spice Up Your Earrings With Microelectronics

December 22, 2023 by Julian Scheffers 9 Comments

We’ve covered [mitxela] in the past and if you know him, you’ll likely know him for putting the micro in microelectronics. This year, he’s at it again with his LED Industrial Piercing.

A T-shaped flexible PCB that is smaller than an index finger — This tiny PCB is really pushing the limits of fabrication

Inspired by the absolutely tiny 0402 LEDs and industrial piercings, [mitxela] started thinking of a way to construct the 5cm long device. He found some normal LED earrings to steal the battery compartment from. Then, with a tick needle and some more steel, he created a new industrial earring with some holes.

Of course, no [mitxela] project is complete without comically tiny microsoldering and this project makes the VQFN ATTiny he used look large. He puts his PCB suppliers to the test with a merely 1mm wide flex PCB for the LEDs to be mounted on. Finally, he combines the flex PCB, the earring and some epoxy to create yet another piece of LED jewelry.

Video after the break.
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Hack A Soda Can Into Jewelry

November 9, 2023 by Al Williams 11 Comments

If you’ve ever needed some aluminum for a project, you might have noticed you have easy access to aluminum cans. If you need a cylinder, fine. But what if you don’t? [ThescientistformerlyknownasNaegeli] shows how to create an attractive necklace from two soda cans, and we think the techniques might be usable for other cases where you might need aluminum. If you care more about the necklace, it looks good. You only have to add a 3D-printed clasp or, if you prefer, you can buy a clasp and use that. For the Hackaday crowd, you can also use the resulting structure as an aluminum cable shield, which might better suit you.

The post gives more details and points to other posts for even deeper dives into many of the steps. But the basic idea is you strip the ink from the outside of the can and then cut the can into a strip. The mechanism for that looks a lot like a machine to cut plastic bottles into strips, but that method isn’t feasible without special blades.

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OpenJewelry, No Pliers Required

July 25, 2022 by Kristina Panos 2 Comments

They say that if you want something done right, you gotta do it yourself. Oftentimes, that goes double for getting something done at all. Whereas some people might simply lament the lack of a (stable) Thingiverse-type site for, say, jewelry designs, those people aren’t Hackaday’s own [Adam Zeloof]. With nowhere to share designs among engineering-oriented friends, [Adam] took the initiative and created OpenJewelry, a site for posting open-source jewelry and wearable art designs as well as knowledge about techniques, materials, and processes.

[Adam] has seeded the site with a handful of his own beautiful designs, which run the gamut from traditional silversmithing techniques to 3D printing to fancy PCBs with working blinkenlights. You really should check it out, and definitely consider contributing.

Even if you don’t have any jewelry designs to share, the code is open as well, or you could even edit the wiki. Just be sure to read through the contribution guidelines first. If you don’t have the time for any of that, donations are welcome as well to help maintain the site.

We love wearable art around here, especially when it serves another purpose like this UV-sensing talisman, or this air quality necklace.

Tiny Talisman Warns Wearer About UV Exposure

November 14, 2021 by Dan Maloney 14 Comments

Given how important our Sun is, our ancestors can be forgiven for seeing it as a god. And even now that we know what it actually is and how it works, it’s not much of a reach to think that the Sun pours forth evil spirits that can visit disease and death on those who bask too long in its rays. So an amulet of protection against the evil UV rays is a totally reasonable project, right?

As is often the case with [mitxela]’s projects, especially the more bedazzled ones, this one is approximately equal parts electronics and fine metalworking. The bulk of the video below focuses on the metalwork, which is pretty fascinating stuff. The case for the amulet was made from brass and sized to fit a CR2032 coin cell. The back of the amulet is threaded to act as a battery cover, and some fancy lathe work was needed there. The case was also electroplated in gold to prevent tarnishing, and lends a nice look when paired up with the black solder mask of the PCB.

On the electronics side, [mitxela] took pains to keep battery drain as low as possible and to make the best use of the available space, choosing an ATtiny84 to support a TTP223 capacitive sensing chip and a VEML6075 UV sensor. The touch sensor allows the wearer to wake the amulet and cycles through UV modes, which [mitxela] learned were not exactly what the sensor datasheet said they were. This required a few software hacks, but in the end, the amulet does a decent job of reporting the UV index and looks fantastic while doing it.

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