Back in the late 90s when absolutely everybody knew that Java was going to become the one programming language to rule them all, the Java Ring was handed out to folks at Java developer conferences as an example of how it was going to revolutionize smart wearable devices. Recently [Daisuke Yamazaki] got his mittens on one of these collector’s items to see about reviving it.

We talked about these rings and associated iButton devices before, with their intended use being primarily to act as authentication keys. For the Java Ring, this use was mostly just used as a kind of gag, whereby visitors to these conferences could specify their coffee preferences at a terminal, having this programmed into the ring so that they could get their desired cup of literal java at various bean juice dispensers around the conference site.

Talking to one of these iButton devices requires a so-called Blue Dot adapter, which [Yamazaki-san] purchased along with the ring. Although the device happily responded on the 1-wire bus, figuring out how to interact with the original Java-based firmware and answering the question of how much of the original information of someone’s coffee preferences in ’98 were retained would require more sleuthing.

After recovering an installer for the Dallas Semiconductor’s IB-DE IDE from the Wayback Machine, this posed the next problem. As it was a 32-bit Java binary, which didn’t play nice with the modern Java 25 runtime and belying the ‘write once, run anywhere’ marketing phrase of back then. Downgrading to 32-bit Java 1.8 with since removed communication APIs helped here.

With the IDE in place, the traffic between the Java Ring and the PC-based software could be analyzed to figure out what was going on. This revealed CRC errors that pointed to the built-in lithium backup battery having expired. Unfortunately the stainless steel case is meant to be sealed and thus turn into e-waste the moment said battery calls it quits. Here fortunately a Japanese TV program picked up on these efforts and featured his efforts on national TV.

This led to the happy ending, with some help with others in replacing this battery. This also answered the question of which parts of the firmware and data were in the battery-backed RAM and which in ROM. Although full details of the findings here are a bit scarce, it seems that the original data was lost along with the dead back-up battery, but the ROM retained the JVM and allowed for a new program to be eventually written to the device and retained across reader sessions.

Although these days the various NFC standards have made bulky devices like iButtons rather obsolete, they’re still a fun look at an era when it was thought that lugging a tiny computer as a (key) ring around for authentication was the future. Of course these days we mostly lug an entire 6″ smartphone for that purpose, so maybe the joke is on us after all.

Thanks to [Wood] for the tip.

In 1675, while transporting a barometer by night, the astronomer Jean Picard noticed a glow inside its glass tube, just above the mercury. As the mercury sloshed and splashed across the surface of the glass, a static electric charge had built up, which was discharging by ionizing the residual gas molecules inside the evacuated tube. [Styropyro] recreated this effect, and found that the dim glow could be made much stronger by adding some noble gas to the tube.

It starts with a simple recreation: he took a volumetric flask, attached a narrow glass stem to the mouth, added some mercury to the flask, evacuated it with a vacuum pump, and sealed off the glass stem. This produced a faint glow when shaken, but it was only really visible under very low light. When [Styropyro] brought it near a Tesla coil, however, it did glow much more brightly.

Backfilling an identical flask with neon to about 40 millitorr produced a much more spectacular result (a low pressure in the tube is necessary, but moderate pressure variations don’t significantly alter the effect). When shaken even slightly, this neon-containing flask produced a bright orange-red glow just above the surface of the mercury. Points of obstruction, such as those in a zig-zag tube, produced a brighter glow. A krypton-containing tube glowed blue, but less brightly than the neon tube.

Since this is, essentially, a triboelectric effect, other materials besides mercury should work; [Styropyro] tested several materials, and found that pieces of Teflon produced a faint glow, and copper beads a somewhat brighter glow. Unfortunately, Galinstan, the obvious replacement for mercury, wets and coats glass, preventing a charge buildup.

Without an added noble gas, the standard glow of barometric light comes from the excitation of mercury vapors, a glow which can also be seen in mercury rectifiers, and which excites the phosphors of fluorescent light bulbs.

Thanks to [Vik Olliver] for the tip!

Although we’d rather bring you news of clever modifications and repairs down on the farm, more often than not, the name “John Deere” has appeared on the pages of Hackaday because of their opposition to farmers actually being able to work on the machines their livelihoods depend on. But thanks to a settlement reached between the company and the Federal Trade Commission this week, farmers seem to have been handed a much-needed win in the Right to Repair battle.

When a lawsuit against a company ends in a settlement, it usually means spending money they would rather pay than go to court. Indeed, earlier cases against John Deere have resulted in plenty of checks being written. But this time around, the FTC agreement requires Deere to make its diagnostic and repair software available to owners and independent shops. It also has a clause that prevents them from retaliating against owners who want to handle their own repairs rather than going through the company’s official service channels — hard to believe that’s something that actually needs to be specified, but it does give you a hint as to just how bad the situation has been. We’ll definitely be keeping an eye on this story.

Sounds like the Feds were busy this week, as the Federal Communications Commission also gave the green light to Reflect Orbital to launch a prototype satellite for their controversial “sunlight as a service” concept. The company plans to put the spacecraft into a roughly 600 km orbit around the planet, where it will deploy its 324-square-meter reflector and angle itself to illuminate a spot on the ground. It might sound like something a Bond villain would come up with, but Reflect Orbital says the capability will be used to beam sunlight directly onto solar panels at night and to provide light for search-and-rescue operations.

As you might expect, providing such a service on a global scale would require many such reflectors, which is where the concern really comes in. Critics note that a sky full of literal mirrors can cause all sorts of issues, ranging from the scientific to the scenic. The American Astronomical Society points out that each satellite in the constellation could appear to be four times as bright as the full Moon, and that it’s possible an amateur sky watcher could get an eyeball full of redirected sunlight should one of them unexpectedly zip past the aperture of their backyard telescope.

Moving from 600 km above to 400 meters below the surface of the ocean, the Royal Canadian Geographical Society and Woods Hole Oceanographic Institution have provided our first look at the wreck of Ernest Shackleton’s final ship, Quest. The schooner-rigged steamship was launched in 1917 and had a storied career that included not only a number of scientific expeditions but service during the Second World War. The ship ultimately met its fate in 1962 when it was damaged by ice and sank off the north coast of Labrador. The exact location of the wreck was unknown until its discovery in June of 2024.

Now, before you start questioning your knowledge of history, we should probably clarify that Shackleton was not exploring the Labrador Sea in 1962. He did, however, die aboard Quest in 1922 at the age of 47 as he was preparing to depart on another expedition to the Antarctic.

This next one isn’t new, but it’s the first time we’ve come across this gallery of gorgeous Soviet-era control rooms. Hackaday isn’t the place to dive into the political and socioeconomic aspects of the USSR. All we know is that they were putting out some damn fine-looking control panels back then. Half of them look like they wouldn’t be out of place on a Moon base, and the white lab coats with the little hats really complete the retrofuturism vibe. Now we have to go watch Chernobyl again.

In software news, FreeCAD has received a new tool that we know many in the community will be excited about: Banana For Scale. Forget the confusion between Metric and Imperial measurements. Placing a 3D banana in the scene alongside your rendered part provides a globally recognized size reference. While the free and open-source CAD package has often been criticized for being behind its commercial counterparts in terms of user interface and overall feature set, we think this addition should go a long way toward evening the scales — no pun intended.

Finally, Phoronix reports that Linux 7.2-rc3 includes several vital updates to device drivers for the Sega Dreamcast. Users running Linux on the ill-fated PlayStation 2 competitor will benefit from improvements made to the keyboard, mouse, and joystick interfaces. These fixes join the improved code for the console’s GD-ROM optical drive that emerged back in April. The “Year of the Linux Desktop” continues to be elusive, but it certainly looks like 2026 may finally be the Year of Linux on the Dreamcast.

See something interesting that you think would be a good fit for our weekly Links column? Drop us a line; we’d love to hear about it.

Preservationists usually take great care to prevent fungi from appearing the world of art, but in the case of [Kexin Wang]’s Funguy project, the fungus itself is the art. It uses a laser diode to repeatedly trace an outline onto a dish of agar gel in which fungus is growing, and the photophobic fungus grows only up to the edge of the laser-traced figure, potentially creating complex designs.

This project evolved out of a research project in which they developed a computer model for fungal growth, then used its predictions and a laser to control a fungus’s growth pattern. The model has two parts: a temporal convolutional neural network which learns fungi growth patterns from a series of images, and a cellular automaton to simulate these growth patterns under different starting conditions. The cellular automaton’s rules aren’t fixed; each cell runs a small neural network which learns the rules under supervision from the convolutional network. By training these networks on images of the growth stages of three different fungi, it was able to realistically predict the different growth patterns of the different species.

To actually control the growth pattern, the researchers tried a series of different wavelengths and laser powers; shorter wavelengths tended to work better, with a 405 nm laser working best. The growth model complemented the laser setup by predicting in which areas the growth medium had run out of nutrients. Since fungus would no longer spread in these regions, the laser no longer needed to trace these sections. The Funguy kit’s laser system itself is similar to a laser engraver, with an XY-kinematic system seemingly built from a DVD drive frame. It uses fungi from the Mucor genus, though it can print with other photophobic microorganisms, such as slime molds.

This project seems aimed at artistic and educational uses, but considering the various electronic parts that have been made of fungi, more functional applications should be possible.

Oh, the farming lifestyle…living off the land, fending for yourself. But who’s got time for all that? For the modern hacker, the best option in the garden space may be this over-engineered automated AI tomato farm created by [Gerd Nicolay]. You can even interact with it right now through the magic of the Internet.

[Gerd] started off with your run-of-the-mill pot and plant, choosing the humble tomato to keep the system simple. Then things started to escalate, with the addition of automatic lighting, watering, and data logging environmental parameters like humidity. Now we’re getting somewhere, but there’s more that can be added. How about an entire AI council to monitor and decide the fate of each individual tomato while recording an entire storyline to go alongside the growing cycle?

That’s right, four different models collaborate to ensure only the utmost quality of care for these tomatoes based on camera feeds, humidity, and various other environmental factors being recorded constantly. Is this a little overkill? Maybe for those who have even a modest sense of gardening knowledge — but who can bash the mountain of documentation and data collection on these wonderful little plants?

Perhaps the best part: you can recommend actions for the AI counsel to take from the comfort of your own web browser. While the TomatoFarm might be slightly unnecessary for the average farmer, if you want to try a more reasonable monitoring system, we have you covered too!