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Hackaday Links: January 19, 2025

This week, we witnessed a couple of space oopsies as both Starship and New Glenn suffered in-flight mishaps on the same day. SpaceX’s Starship was the more spectacular, with the upper stage of the seventh test flight of the full stack experiencing a “rapid unscheduled disassembly” thanks to a fire developing in the aft section of the stage somewhere over the Turks and Caicos islands, about eight and a half minutes after takeoff from Boca Chica. The good news is that the RUD happened after first-stage separation, and that the Super Heavy booster was not only able to safely return to the pad but also made another successful “chopsticks” landing on the tower. Sorry, that’s just never going to get old.

On the Bezos side of the billionaire rocket club, the maiden flight of Blue Origin’s New Glenn ended with the opposite problem. The upper stage reached orbit, but the reusable booster didn’t make it back to the landing barge parked off the Bahamas. What exactly happened isn’t clear yet, but judging by the telemetry the booster was coming in mighty fast, which may indicate that the engines didn’t restart fully and the thing just broke up when it got into the denser part of the atmosphere.

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Taser Ring Is Scary Jewelry You Shouldn’t Build

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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Unusual Tool Gets An Unusual Repair

In today’s value-engineered world, getting a decade of service out of a cordless tool is pretty impressive. By that point you’ve probably gotten your original investment back, and if the tool gives up the ghost, well, that’s what the e-waste bin is for. Not everyone likes to give up so easily, though, which results in clever repairs like the one that brought this cordless driver back to life.

The Black & Decker “Gyrodriver,” an interesting tool that is controlled with a twist of the wrist rather than the push of a button, worked well for [Petteri Aimonen] right up until the main planetary gear train started slipping thanks to stripped teeth on the plastic ring gear. Careful measurements of one of the planetary gears to determine parameters like the pitch and pressure angle of the teeth, along with the tooth count on both the planet gear and the stripped ring.

Here, most of us would have just 3D printed a replacement ring gear, but [Petteri] went a different way. He mentally rolled the ring gear out, envisioning it as a rack gear. To fabricate it, he simply ran a 60° V-bit across a sheet of steel plate, creating 56 parallel grooves with the correct pitch. Wrapping the grooved sheet around a round form created the ring gear while simultaneously closing the angle between teeth enough to match the measured 55° tooth angle in the original. [Petteri] says he soldered the two ends together to form the ring; it looks more like a weld in the photos, but whatever it was, the driver worked well after the old plastic teeth were milled out and the new ring gear was glued in place.

We think this is a really clever way to make gears, which seems like it would work well for both internal and external teeth. There are other ways to do it, of course, but this is one tip we’ll file away for a rainy day.

The ring shown on someone's index finger

The ErgO Ring Makes Computer Interactions Comfortable

[Sophia Dai] brings us a project you will definitely like if you’re tired of traditional peripherals like a typical keyboard and mouse combo. This is ErgO, a smart ring you can build out of a few commonly available breakouts, and it keeps a large number of features within a finger’s reach. The project has got an IMU, a Pimoroni trackball, and a good few buttons to perform actions or switch modes, and it’s powered by a tiny Bluetooth-enabled devboard so it can seamlessly perform HID device duty.

While the hardware itself appears to be in a relatively early state, there’s no shortage of features, and the whole experience looks quite polished. Want to lay back in your chair yet keep scrolling the web, clicking through links as you go? This ring lets you do that, no need to hold your mouse anymore, and you can even use it while exercising. Want to do some quick text editing on the fly? That’s also available; the ErgO is designed to be used for day to day tasks, and the UX is thought out well. Want to use it with more than just your computer? There is a device switching feature. The build instructions are quite respectable, too – you can absolutely build one like this yourself, just get a few breakouts, a small battery, some 3D printed parts, and find an evening to solder them all together. All code is on GitHub, just like you would expect from a hack well done.

Looking for a different sort of ring? We’ve recently featured a hackable cheap smart ring usable for fitness tracking – this one is a product that’s still being reverse-engineered, but it’s alright if you’re okay with only having an accelerometer and a few optical sensors.

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A closeup of the ring, inner electronics including a lit green LED seen through the inner transparent epoxy, next to the official app used to light up the LED for a demo.

New Part Day: A Hackable Smart Ring

We’ve seen prolific firmware hacker [Aaron Christophel] tackle smart devices of all sorts, and he never fails to deliver. This time, he’s exploring a device that seems like it could have come from the pages of a Cyberpunk RPG manual — a shiny chrome Bluetooth Low Energy (BLE) smart ring that’s packed with sensors, is reasonably hacker friendly, and is currently selling for as little as $20.

The ring’s structure is simple — the outside is polished anodized metal, with the electronics and battery carefully laid out along the inside surface, complete with a magnetic charging port. It has a BLE-enabled MCU, a heartrate sensor, and an accelerometer. It’s not much, but you can do a lot with it, from the usual exercise and sleep tracking, to a tap-sensitive interface for anything you want to control from the palm of your hand. In the video’s comments, someone noted how a custom firmware for the ring could be used to detect seizures; a perfect example of how hacking such gadgets can bring someone a brighter future.

The ring manufacturer’s website provides firmware update images, and it turns out, you can upload your own firmware onto it over-the-air through BLE. There’s no signing, no encryption — this is a dream device for your purposes. Even better, the MCU is somewhat well-known. There’s an SDK, for a start, and a datasheet which describes all you would want to know, save for perhaps the tastiest features. It’s got 200 K of RAM, 512 K of flash, BLE library already in ROM, this ring gives you a lot to wield for how little space it all takes up. You can even get access to the chip’s Serial Wire Debug (SWD) pads, though you’ve got to scrape away some epoxy first.

As we’ve seen in the past, once [Aaron] starts hacking on these sort of devices, their popularity tends to skyrocket. We’d recommend ordering a couple now before sellers get wise and start raising prices. While we’ve seen hackers build their own smart rings before, it’s tricky business, and the end results usually have very limited capability. The potential for creating our own firmware for such an affordable and capable device is very exciting — watch this space!

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LED Ring Brings The Bling

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.

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Hackaday Links: March 12, 2023

With a long history of nearly universal hate for their products, you’d think printer manufacturers would by now have found ways to back off from the policies that only seem to keep aggravating customers. But rather than make it a financially wiser decision to throw out a printer and buy a new one than to buy new ink cartridges or toners, manufacturers keep coming up with new and devious ways to piss customers off. Case in point: Hewlett-Packard now seems to be bricking printers with third-party ink cartridges. Reports from users say that a new error message has popped up on screens of printers with non-HP cartridges installed warning that further use of the printer has been blocked. Previously, printers just warned about potential quality issues from non-HP consumables, but now they’re essentially bricked until you cough up the money for legit HP cartridges. Users who have contacted HP support say that they were told the change occurred because of a recent firmware update sent to the printer, so that’s comforting.

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