Mysterious Files PH

There are many chess robots, most of which require the human player to move the opposing pieces themselves, or have a built-in mechanism that can slide the opposing pieces around to their new location. Ideally, such a chess robot would move the pieces just like how a human would, of course. That’s pretty much the promise behind the Manya Cynus chess robot, which [Matt] over at the Techmoan YouTube channel bought from the Kickstarter campaign.

Advertising itself as a ‘Portable AI Chess Robot’, the Manya Cynus chess robot comes in the form of a case that unfolds into a chess board and also contains the robotic arm that contains the guts of the operation. Powered by the open source Stockfish chess engine, it can play games against a human opponent at a few difficulty levels without requiring any online connectivity or a companion app. It moves its own pieces by picking up the metal-cored chess pieces with its arm, while its front display tries to display basic emotions with animated eyes. A 3-MP downward-facing camera is located on the head section, along with a microphone.

As for how well it works, [Matt] isn’t the best chess player, but he had a fair bit of fun with the machine. His major complaints circle around how unfinished the firmware still feels, with e.g., invalid moves basically ignored with only a barely visible warning popping up on the screen. In general, he’d rather classify it as an interesting development kit for a chess robot, which is where the BLE 5.1-based interface and a purported Python-based development environment provided by Manya seem to come into focus.

From the site, it’s not clear where this documentation and software can be found, and the chess robot appears to be fully sold out on the Kickstarter page. In addition to this, a promised companion app seems to have gone AWOL, too.

With no clear support or even availability, it would seem that this is less of a crowdfunding scam and more of a confusing product which may or may not become available again, yet which could perhaps provide inspiration to some DIY projects, as the basic principle seems sound enough. Or, keep it simple and use a gantry.

Many different types of printers have entered the market over the years. Most of us are intimately familiar with the common inkjet and laser, both of which can be found in homes and offices all over the world. Then there are those old dot matrix printers that were so noisy in use, thermal printers, and even solid ink printers that occupied a weird niche for a time.

However, very little attention is ever paid to the LED printer. They’re not actually that uncommon, and they work in a very familiar way. It’s just that because these printers are so similar to an existing technology, they largely escaped any real notability in the marketplace. Let’s explore the inner workings of the printer tech that the world forgot.

Blinding Lights

To understand the LED printer, it helps to first understand the laser printer, and before that, the photocopier. Indeed, it was the latter technology that spawned the xerographic process that underpins all three machines.

Xerography is a compound word, from the Greek words xeros (dry) and graphia (writing). It’s where the Xerox company earned its name, and the process is at the heart of the photocopier. In the modern form we’re all familiar with, a photocopier relies on the use of a cylindrical drum, coated in a photoconductive material. This drum can be given an electrostatic charge, which remains on the surface when in darkness, but is conducted away when exposed to light. In a photocopier, the drum is exposed to light from a scanning lamp passing over a document. Where the document has light sections, the charges on the drum are conducted away, and where there are dark sections, the charge remains. The drum is then exposed to tiny particles of toner, which are attracted to the charged areas on the drum. A corona wire is then used to generate an opposite charge to that of the toner, pulling it off the drum and onto a piece of paper to replicate the original document. It’s then merely a matter of heating the paper to fuse the toner in place by melting it, and then the completed document is fed out of the photocopier. It’s this final step that gives fresh photocopies their characteristic warm feel and mild plasticky smell.

It wasn’t long before the xerography process was applied beyond mere photocopies. Xerox engineer Gary Starkweather realized in 1969 that a scanning laser beam could be used to draw directly on to the drum in place of the scanning lamp of a photocopier. A few years later, this led to the development of a prototype which proved the concept, and by 1976, the first commercial laser printer was on the market.

These printers were prized for their high speed and initially used in data center roles, before smaller desktop-sized units reached the market in the 1980s. Laser printers vary in construction, but most use a single laser diode with a rotating mirror that scans the beam over the drum. The beam is modulated as the mirror scans and the drum rotates to only remove charges from the drum in light areas that are not to have toner deposited. For color printing, some laser printers implement multiple drums, one for each color of toner—cyan, magenta, yellow, and key (black)—with four scanning lasers required in turn. The paper is passed over each, picking up one layer of toner at a time before it’s fused into the paper to create the final image. Some printers have also added a “transfer belt” to ease registration issues in color printers, wherein the drums deliver each color of toner to a belt, and the belt then delivers the toner to the paper in one fell swoop.

Laser printers are capable, high-speed printing machines, but they are expensive and do have a lot of moving parts. Engineers at Oki eventually realized it was possible to replace the combined laser diode and spinning mirror assembly with something simpler and more solid-state. Thus was born the LED printer, first developed in 1981 and commercialized in 1986. Rather than scanning a laser beam across a cylindrical drum, the LED printer has a line array of tiny individual LEDs that remove charges from the drum instead. The printer otherwise works in pretty much exactly the same way—only the method of discharging the drum was changed.

LED printers are generally a bit cheaper to manufacture, and can sometimes print faster than comparable laser printers. In part, this is because the line array can flash a segment of the drum all at once versus a laser beam which must be scanned across it. Where laser printers routinely offer 1200 x 2400 DPI resolution, it took LED printers some time to reach the same heights, as fitting 1200 LEDs into a single inch is no mean feat. However,  Oki was able to achieve this milestone by 1997, while some cheaper models sit at the 600 DPI level instead. Meanwhile, in 2024, Canon did produce a LED-type printer using OLED technology, which enabled resolutions up to 4800 x  2400 DPI. The higher light emitter density possible with OLED technology allowed this leap forward.

Notably, most color LED printers tend to use a transfer belt setup, in which each LED/drum unit delivers toner to the belt which is then deposited on the paper in one pass. This is why LED printers tend to have similar print speeds for color and black-an-white use. This was an advantage over older color laser printers that didn’t use transfer belts, but instead had a color page make four separate passes over a drum, slowing printing down significantly.

Canon leveraged OLED technology to produce an LED-type printer with far superior resolution to traditional designs.

Funnily enough, some LED printers fly under the radar and are sold as “laser printers” despite not containing a laser. This is because, to the end user, the technology is not particularly different—the printers still use a charged drum for printing and still use toner to make an image. LED printers never differentiated themselves enough to make a big splash with disinterested consumers and commercial buyers who just want well-printed documents at the end of the day. LED printers mostly just look like laser printers and work similarly enough that few ever noticed the difference. Often, an LED printer will show up on e-commerce sites with “laser” scattered around the marketing copy because many understand them to be essentially the same thing from a user perspective.

LED printers are unlikely to become a household name any time soon, even if you have one in your household—if only because their close association with laser printing technology means most people never noticed they existed in the first place. In any case, next time you’re sitting at a table at your friend’s wedding with a bunch of people you’ve never met before, you now have an incredibly tedious technical lecture you can deliver to impress everybody at dinner. Spread the word about LED printers, because they’ve failed to do it themselves!

Liquid nitrogen isn’t exactly an everyday material, but it’s acquired conveniently enough to be used in extreme overclocking experiments, classroom demonstrations, chemistry and physics experiments, and a number of other niche applications. Liquid oxygen, by contrast, is dangerous enough that it’s only really used in rocket engines. Nevertheless, [Electron Impressions] made some of his own, and beyond the obvious pyrotechnic experimentation, demonstrated its unusual magnetic properties. Check out the video, below.

The oxygen in this case was produced by electrolysis through a proton-exchange membrane, which vented the hydrogen into the atmosphere and routed the oxygen into a Dewar flask mounted at the cold end of a Stirling cryo-cooler. The cooler had enough power to produce about 30 to 40 milliliters of liquid oxygen per hour, enough to build up an appreciable amount in short order. As expected, the pale blue liquid caused burning paper to disappear in a violent flame, and a piece of paper soaked in it almost exploded when ignited.

More interestingly, a piece of oxygen-soaked paper could also be picked up with a strong enough magnet. This is due to molecular oxygen’s paramagnetism, which is too weak to be significant in a gas made of quickly-moving molecules, but becomes noticeable in a liquid. When some liquid oxygen was poured onto a strong magnet, it stuck to the edges of the magnet, whereas liquid nitrogen just splashed away. Even as the liquid oxygen evaporated, it was possible to faintly see some of the cold vapours sticking close to the magnet. [Electron Impressions] tried to create a kind of coil gun by wrapping a coil around a test tube containing liquid oxygen, but it didn’t really work. Any effect was imperceptible among the disturbances caused by boiling oxygen and the physical jolt of the power supply connecting.

It’s not a process we’ve seen before, but the boiling point of liquid nitrogen is lower than the boiling point of oxygen, so if you have a convenient source of liquid nitrogen, it’s simple enough to make liquid oxygen.

[Nagy Krisztián] had an Intel 286 CPU, only… There was no motherboard to install it in. Perhaps not wanting the processor to be lonely, [Nagy] built a simulated system to bring the chip back to life.

The concept is simple enough. [Nagy] merely intended to wire the 286 up to a Raspberry Pi Pico that could emulate other parts of a computer that it would normally expect to talk to. This isn’t so hard with an ancient CPU like the 286, which has just 68 pins compared to the 1000+ pins on modern CPUs. All it took was a PLCC-68 socket, an adapter PCB, a breadboard, and some MCP23s17 logic expanders to give the diminutive microcontroller enough I/O. With a bit of work, [Nagy] was able to get the Pi Pico running the 286, allowing it to execute a simple program that retrieves numbers from “memory” and writes them back in turn.

Notably, this setup won’t run the 286 at its full clock speed of 12 MHz, and it’s a long way off from doing anything complex like talking to peripherals or booting an OS. Still, it’s neat to see the old metal live again, even if it’s just rattling through a few simple machine instructions that don’t mean a whole lot. [Nagy] equates this project to The Matrix; you might also think of it as a brain in a jar. The 286 is not in a real computer; it’s just hooked up to a microcontroller stimulating its various pins in a way that is indistinguishable from its own perspective.

We’ve seen similar retro projects before, such as this FPGA rig that helped a NEC V20 get back on its feet. If you’re doing your own tinkering on the platforms of yesteryear, we probably want to know about it on the tips line.

We’ll start this week off with a bit of controversy from Linux Land. Anyone who’s ever used the sudo command knows that you don’t see any kind of visual feedback while entering your password. This was intended as a security feature, as it was believed that an on-screen indicator of how many characters had been entered would allow somebody snooping over your shoulder to figure out the length of your password. But in Ubuntu 26.04, that’s no longer the case. The traditional sudo binary has been replaced with a one written in Rust, which Canonical has recently patched to follow the modern convention of showing asterisks on the password prompt.

As you might expect, this prompted an immediate reaction from Linux greybeards. A bug report was filed just a few days ago demanding that the change be reverted, arguing that breaking a decades-old expectation with no warning could be confusing for users. The official response from a Canonical dev was that they see it the other way around, and that the change was made to improve the user experience. It was also pointed out that those who want to revert to the old style of prompt can do so with a config change. The issue was immediately marked as “Won’t Fix”, but the discussion is ongoing.

Speaking of unexpected changes, multiple reports are coming in that the February security update for Samsung Galaxy devices, which is currently rolling out, removes several functions from the Android recovery menu. After the update is applied to phones such as the S25 and Fold 7, long-standing features, such as the ability to wipe the device’s cache partition or install updates via Android Debug Bridge (ADB), disappear.

Just like with the change to sudo, this is the sort of thing that will aggravate veteran users the most. There’s been no official explanation for these changes, and it’s not immediately obvious why Samsung would fiddle with the recovery menu that’s remain largely unchanged since Android’s introduction. As 9to5Google mentions, it could be an attempt to prevent users from installing leaked firmware builds — a practice that’s gotten the attention of the electronic giant’s legal department.

These days, software updates are just one of the things you need to keep track of. Add in emails, RSS feeds, and incoming chat messages, and keeping up with the notifications on your computer or smartphone can be a challenge. But that’s nothing compared to the 800,000 alerts fired off earlier this week by the Vera Rubin Observatory. The observatory uses a 3.2 gigapixel camera to take long exposure images of the night sky, which are then compared with earlier shots to detect visual changes. Astronomers create filters to narrow down what they’re after, and can be notified when the automated system detects a match. A preview image is available in just seconds, while the full-resolution imagery takes around 80 hours to process. It’s still early days, but once the VRO gets up to speed, it’s expected that as many as seven million alerts will be generated each night.

While on the subject of large-scale engineering projects, this week, Google announced that its new data center in Minnesota will be hooked up to the world’s largest battery. The 300 megawatt array built by Form Energy will use iron-air technology, which essentially uses a reversible rusting process to store energy produced by renewable sources such as wind and solar. When those sources aren’t available, the data center can run off of battery power for up to 100 hours.

While heavier and less efficient than lithium-ion, iron-air batteries have the advantage of being substantially cheaper to produce. So while it’s unlikely you’ll see the technology in smartphones anytime soon, it’s perfect for static installations like this.

Finally, some sad news from the world of retro computing/games: a very rare copy of Tsukihime Trial Edition was apparently destroyed while in transit from one collector to another. It might not look like much — the game was distributed by the indie developers on unbranded floppies at a Japanese convention in 1999 — but it represents one of only 50 copies known to exist. While the occasional damaged package is all but unavoidable, this one is particularly egregious as it appears that someone at US Customs intentionally ripped the disk to pieces. The purchaser has filed a complaint with Customs, and we’re interested in hearing what their version of the story sounds like.

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.

Water-cooled PCs generally have in common that there’s a radiator somewhere in the loop, yet nobody said that you can’t build the PCB into the radiator. Something like a genuine Victorian-era cast-iron radiator, for example. For the folk over at [Billet Labs], this is just your typical project, of course, even if it took a solid three months to make it all work.

Their previous project was also a water-cooled PC, but in the form of a steampunk-esque wall-mounted installation. What differentiates this new build is that it’s trying to be more of a sleeper PC, as long as you ignore some copper tubing and the like running around the outside of this vintage radiator.

Of course, by using a vintage cast-iron radiator like this, you’re also dealing with all the disadvantages of cast-iron, such as the countless impurities in the metal and the immense weight. With water in the loop, the entire build comes in at about 99 kilograms, and cleaning the radiator of particulates released inside it — including rust — was a challenge.

With the amount of water inside the loop, it was little surprise that even a computer stress test only raised the water temperature by two degrees, but the main takeaway from the project was that cast-iron in a water loop is a pain, even with a galvanic corrosion inhibitor. For this reason, the video’s comment section mentioned [gsuberland], for example, mentioning chemical passivation, referencing steel sanitary pipes, and the formation of a nitride layer.

Maybe using a more modern, pure steel radiator would be easier here for that reason, but we can only admire [Billet Labs] for persevering with this project. As a bonus, this is also pretty much a guaranteed theft-proof PC, as even his massive new TV and sound setup weigh less combined, and are probably infinitely more portable. Or, you could choose to go ultra-modern for a futuristic look instead.

Fish are popular animals to keep as pets, and for good reason. They’re relatively low maintenance, relaxing to watch, and have a high aesthetic appeal. But for all their upsides, they aren’t quite as companionable as a dog or a cat. Although some fish can do limited walking or flying, these aren’t generally kept as pets and would still need considerable help navigating the terrestrial world. To that end, [Everything is Hacked] built a fish tank that allows his fish to move around on their own. We presume he’s heard the old joke about two fish in a tank. One says, “Do you know how to drive this thing?”

The first prototype of this “fish tank” is actually built on a tracked vehicle with differential steering, on which the fish tank would sit. But after building a basic, driveable machine, the realities of fish ownership set in. The fish with the smallest tank needs is a betta fish, but even that sort of fish needs much more space than would easily fit on a robotics platform. So [Everything is Hacked] set up a complete ecosystem for his new pet, making the passenger vehicle a secondary tank.

The new fish’s name is [Carrot], named after the carrots that [Everything is Hacked] used to test the computer vision system that would track the fish’s movements and use them to control the mobile fish tank. There was some configuration needed to ensure that when this feisty fish swam in circles, the tank didn’t spin around uncontrollably, but eventually he was able to get it working in an “arena” where [Carrot] could drive towards some favorite items he might like to interact with. Mostly, though, he drove his tank to investigate the other fish in the area.

The ultimate goal was for [Everything is Hacked] to take his fish on a walk, though, so he set about training [Carrot] to respond to visual cues and swim towards them. In theory, this would have allowed him to be followed by his fish tank, but a test at a local grocery did not go as smoothly as hoped. Still, it’s an interesting project that pushes the boundaries of pet ownership much like other fish-driving projects we’ve seen.