Open-Source Knob Packed With Precision

June 28, 2025 by Matt Varian 61 Comments

The world of custom mechanical keyboards is vibrant, with new designs emerging weekly. However, keyboards are just one way we interact with computers. Ploopy, an open-source hardware company, focuses on innovative user interface devices. Recently, [Colin] from Ploopy introduced their latest creation: the Ploopy Knob, a compact and thoughtfully designed control device.

At first glance, the Ploopy Knob’s low-profile design may seem unassuming. Housed in a 3D-printed enclosure roughly the size of a large wristwatch, it contains a custom PCB powered by a USB-C connection. At its core, an RP2040 chip runs QMK firmware, enabling users to easily customize the knob’s functions.

The knob’s smooth rotation is achieved through a 6705ZZ bearing, which connects the top and bottom halves and spans nearly the device’s full width to eliminate wobble. Unlike traditional designs, the Ploopy Knob uses no mechanical encoder or potentiometer shaft. Instead, an AS5600 magnetic encoder detects movement with remarkable precision. This 12-bit rotary encoder can sense rotations as fine as 0.088 degrees, offering 4096 distinct positions for highly accurate control.

True to Ploopy’s philosophy, the Knob is fully open-source. On its GitHub Page, you’ll find everything from 3D-printed case files to RP2040 firmware, along with detailed guides for assembly and programming. This transparency empowers users to modify and build their own versions. Thanks to [Colin] for sharing this innovative device—we’re excited to see more open-source hardware from Ploopy. For those curious about other unique human-machine interfaces, check out our coverage of similar projects. Ploopy also has designs for trackballs (jump up a level on GitHub and you’ll see they have many interesting designs).

Reading The Chip In Your Passport

June 28, 2025 by Jenny List 37 Comments

For over a decade, most passports have contained an NFC chip that holds a set of electronically readable data about the document and its holder. This has resulted in a much quicker passage through some borders as automatic barriers can replace human officials, but at the same time, it adds an opaque layer to the process. Just what data is on your passport, and can you read it for yourself? [Terence Eden] wanted to find out.

The write-up explains what’s on the passport and how to access it. Surprisingly, it’s a straightforward process, unlike, for example, the NFC on a bank card. Security against drive-by scanning is provided by the key being printed on the passport, requiring the passport to be physically opened.

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Ancient SoundBlaster Cards Just Got A Driver Update

June 28, 2025 by Lewin Day 11 Comments

Old hardware tends to get less support as the years go by, from both manufacturers and the open-source community alike. And yet, every now and then, we hear about fresh attention for an ancient device. Consider the ancient SoundBlaster sound card that first hit the market 31 years ago. [Mark] noticed that a recent update squashed a new bug on an old piece of gear.

Jump over to the Linux kernel archive, and you’ll find a pull request for v6.16-rc3 from [Takashi Iwai]. The update featured fixes for a number of sound devices, but one stands out amongst the rest. It’s the SoundBlaster AWE32 ISA sound card, with [Iwai] noting “we still got a bug report after 25 years.” The bug in question appears to have been reported in 2023 by a user running Fedora 39 on a 120 MHz Pentium-based machine.

The fixes themselves are not particularly interesting. They merely concern minutiae about the DMA modes used with the old hardware. The new updates ensure that DMA modes cannot be changed while the AWE32 is playing a PCM audio stream, and that DMA setups are disabled when changing modes. This helps avoid system lockups and/or ugly noises emanating from the output of the soundcard.

It’s incredibly unlikely this update will affect you, unless you’re one of a handful of users still using an ISA soundcard in 2025. Still, if you are — and good on you — you’ll be pleased someone still cares about your user experience. Meanwhile, if you’re aware of any other obscure old-school driver updates going on out there, don’t hesitate to let us know on the tips line. Want to relive your ISA card’s glory days? Plug it into USB.

Image credit: Gona.eu, CC BY-SA 3.0

[Thanks to Meek Mark for the tip!]

Making Optical Glass From Ceran Stovetops

June 28, 2025 by Maya Posch 2 Comments

The Ceran discs, freshly cut from the old stovetop and awaiting polishing. (Credit: Huygens Optics)

Ceran is a name brand for a type of glass ceramic that has a very low coefficient of thermal expansion (CTE). This is useful for stovetops, but it is also a highly desirable property for optical glass. The natural question: Can an old ceramic stovetop be upcycled into something visually striking? This is the topic of the most recent video in [Huygens Optics]’s series on glass ceramics.

Interestingly, by baking sections of the Ceran glass ceramic for 10 minutes at 961 °C, the CTE can be lowered by another five times, from 0.5 ppm / °C to a mere 0.1 ppm / °C. Following baking, you need a lot of grinding and polishing to remove any warping, existing textures, and printing. After polishing with 220 grit by hand for a few minutes, most of these issues were fixed, but for subsequent polishing, you want to use a machine to get the required nanometer-level precision, as well as to survive the six to eight hours of polishing.

Following this final polishing, the discs were ground into mirrors for a Newtonian telescope. This raised a small issue of the Ceran being only 4 mm thick, which requires doubling up two of the discs using a very thin layer of epoxy. After careful drilling, dodging cracked glass, and more polishing, this produced the world’s first ceramic stovetop upcycled into a telescope. We think it was the first, anyway. All that’s left is to coat the discs with a more reflective coating and install them into a telescope frame, but even in their raw state, they show the potential of this kind of material.

If you decide to try this, and you’ve already cut up your stove, you might as well attack some kitchen bowls, too.

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BeyBlades Made Ever More Dangerous With 3D Printing

June 28, 2025 by Lewin Day 11 Comments

If you’re unfamiliar with Beyblades, they’re a simple toy. They consist of spinning tops, which are designed to “fight” in arenas by knocking each other around. While the off-the-shelf models are deemed safe enough for children to play with, [Jon Bringus] decided to take the danger level up a few notches with some custom launchers of his own design.

[Jon]’s project started with some of the early metal Beyblades, which are traditionally launched with a small geared ripcord device. He soon realized he could up the action by doing one simple thing—spinning the tops far faster than the manufacturer ever intended. More rotational speed equals more kinetic energy equals more ~~legal liability~~ fun, or so the equation goes.

The design for [Jon’s] “WMD Launcher” is straightforward enough—he combined a lawnmower pull starter with a 12:1 geartrain to turn the Beyblades at truly ludicrous speeds. It’s basic engineering — a couple of 3D-printed gears do the job — but the results are hilarious. The tops begin to emit loud noises as they turn in combat, and some move so fast and erratically that they won’t even stay inside the arena. Protective eyewear is virtually mandatory. Files are on Printables for those eager to build one at home.

Yes, ruining a game of Beyblades is as simple as building an irresponsibly fast launcher. You needn’t even use some fancy brushless motor to hurt yourself — just a little gearing is enough to cause havoc. We’ve featured similar work on this topic before, too. Video after the break.

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Limitations, Creativity, And Challenges

June 28, 2025 by Elliot Williams 6 Comments

This week, we announced the winners for the previous Pet Hacks contest and rang in our new contest: The One Hertz Challenge. So that’s got me in a contesty mood, and I thought I’d share a little bit of soap-box philosophizing and inside baseball all at once.

The trick to creating a good contest theme, at least for the creative Hackaday crowd, is putting on the right limitation. Maybe you have to fit the circuit within a square-inch, power it only with a coin cell, or use the antiquated and nearly useless 555 timer IC. (Yes, that was a joke!)

There are two basic reactions when you try to constrain a hacker. Some instantly try to break out of the constraint, and their minds starts to fly in all of the directions that lead out of the box, and oftentimes, something cool comes out of it. The other type accepts the constraint and dives in deep to work within it, meditating deeply on all the possibilities that lie within the 555.

Of course, we try to accommodate both modes, and the jury is still out as to which ends up better in the end. For the Coin Cell challenge, for instance, we had a coin-cell-powered spot welder and car jumpstarter, but we also had some cool circuits that would run nearly forever on a single battery; working against and with the constraints.

Which type of hacker are you? (And while we’re still in the mood, what contest themes would you like to see for 2026?)

Behind The Bally Home Computer System

June 28, 2025 by Bryan Cockfield 9 Comments

Although we might all fundamentally recognize that gaming consoles are just specialized computers, we generally treat them, culturally and physically, differently than we do desktops or laptops. But there was a time in the not-too-distant past where the line between home computer and video game console was a lot more blurred than it is today. Even before Microsoft entered the scene, companies like Atari and Commodore were building both types of computer, often with overlapping hardware and capabilities. But they weren’t the only games in town. This video takes a look at the Bally Home Computer System, which was a predecessor of many of the more recognized computers and gaming systems of the 80s.

At the time, Bally as a company was much more widely known in the pinball industry, but they seemed to have a bit of foresight that the computers used in arcades would eventually transition to the home in some way. The premise of this console was to essentially start out as a video game system that could expand into a much more full-featured computer with add-ons. In addition to game cartridges it came with a BASIC interpreter cartridge which could be used for programming. It was also based on the Z80 microprocessor which was used in other popular PCs of the time, so in theory it could have been a commercial success but it was never able to find itself at the top of the PC pack.

Although it maintains a bit of a cult following, it’s a limited system even by the standards of the day, as the video’s creator [Vintage Geek] demonstrates. The controllers are fairly cumbersome, and programming in BASIC is extremely tedious without a full keyboard available. But it did make clever use of the technology at the time even if it was never a commercial success. Its graphics capabilities were ahead of other competing systems and would inspire subsequent designs in later systems. It’s also not the last time that a video game system that was a commercial failure would develop a following lasting far longer than anyone would have predicted.

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