2026-03-06 05:00:37
It’s one thing to create your own relay-based computer; that’s already impressive enough, but what really makes [DiPDoT]’s design special– at least after this latest video— is swapping the SRAM he had been using for historically-plausible capacitor-based memory.
A relay-based computer is really a 1940s type of design. There are various memory types that would have been available in those days, but suitable CRTs for Williams Tues are hard to come by these days, mercury delay lines have the obvious toxicity issue, and core rope memory requires granny-level threading skills. That leaves mechanical or electromechanical memory like [Konrad Zeus] used in the 30s, or capacitors. he chose to make his memory with capacitors.
It’s pretty obvious when you think about it that you can use a capacitor as memory: charged/discharged lets each capacitor store one bit. Charge is 1, discharged is 0. Of course to read the capacitor it must be discharged (if charged) but most early memory has that same read-means-erase pattern. More annoying is that you can’t overwrite a 1 with a 0– a separate ‘clear’ circuit is needed to empty the capacitor. Since his relay computer was using SRAM, it wasn’t set up to do this clear operation.
He demonstrates an auto-clearing memory circuit on breadboard, using 3 relays and a capacitor, so the existing relay computer architecture doesn’t need to change. Addressing is a bit of a cheat, in terms of 1940s tech, as he’s using modern diodes– though of course, tube diodes or point-contact diodes could conceivably pressed into service if one was playing purist. He’s also using LEDs to avoid the voltage draw and power requirements of incandescent indicator lamps. Call it a hack.
He demonstrates his circuit on breadboard– first with a 4-bit word, and then scaled up to 16-bit, before going all way to a massive 8-bytes hooked into the backplane of his Altair-esque relay computer. If you watch nothing else, jump fifteen minutes in to have the rare pleasure of watching a program being input via front panel with a complete explanation. If you have a few extra seconds, stay for the satisfyingly clicky run of the loop. The bonus 8-byte program [DiPDoT] runs at the end of the video is pure AMSR, too.
Yeah, it’s not going to solve the rampocalypse, any more than the initial build of this computer helped with GPU prices. That’s not the point. The point is clack clack clack clack clack, and if that doesn’t appeal, we don’t know what to tell you.
2026-03-06 03:30:03
Most end tables that you might find in a home are relatively static objects. However, [Peter Waldraff] of Tiny World Studios likes to build furniture that’s a little more interesting. Thus came about this beautiful piece with a real working railway built right in.
The end table was built from scratch, with [Peter] going through all the woodworking steps required to assemble the piece. The three-legged wooden table is topped with a tiny N-scale model railway layout, and you get to see it put together including the rocks, the grass, and a beautiful epoxy river complete with a bridge. The railway runs a Kato Pocket Line trolley, but the really neat thing is how it’s powered.
[Peter] shows us how a small gearmotor generator was paired with a bridge rectifier and a buck converter to fill up a super capacitor that runs the train and lights up the tree on the table. Just 25 seconds of cranking will run the train anywhere from 4 to 10 minutes depending on if the tree is lit as well. To top it all off, there’s even a perfect coaster spot for [Peter]’s beverage of choice.
It’s a beautiful kinetic sculpture and a really fun way to build a small model railway that fits perfectly in the home. We’ve featured some other great model railway builds before, too.
2026-03-06 02:00:02
Curious about split keyboards, but overwhelmed by the myriad options for every little thing? You should start with [thehaikuza]’s excellent Beginner’s Guide to Split Keyboards.
He then gets into the types of keyboards — you got your standard row-staggered rectangles that we all grew up on, column-staggered, and straight-up ortholinear, which no longer enjoy the popularity they once did.
At this point, the guide becomes a bit of a Choose Your Own Adventure story. If you want a split but don’t want to learn to change much if at all about your typing style, keep reading, because there are definitely options.
But if you’re ready to commit to typing correctly for the sake of ergonomics, you can skip the Alice and other baby ergo choices and get your membership to the light side. First are features — you must decide what you need to get various jobs done. Then you learn a bit about key map customization, including using a non-QWERTY layout. Finally, there’s the question of buying versus DIYing. All the choices are yours, so go for it!
Via reddit
Need something ultra-portable for those impromptu sessions at the coffee shop (when you can actually find a table)? You can’t get much smaller than the 28-key Koumori by [fata1err0r81], which means “bat” in Japanese. Here’s the repo.
Protecting that glass overlay is a case with a handle and a magnetic lid. Both the PCB and the case were designed in Ergogen, which as you know, I really like to see people using.
As you might have guessed, those are Kailh V1 choc switches with matching key caps. If you want a bat for your pocket, the build guide is simple, and there aren’t even any microscopic parts involved.
So [arax20] built this as a gift for an ex. She likes the ergonomics of splits, but didn’t want cables between the halves and feels the space between is otherwise wasted. Really? There’s so much you can put there, from cats to mice to coffee mugs.
Do you rock a sweet set of peripherals on a screamin’ desk pad? Send me a picture along with your handle and all the gory details, and you could be featured here!
Frustratingly little is known about the Rico, a 1932 index machine out of Nuremburg, Germany. But the Antikey Chop has over a dozen books on typewriters, and only two have any mention of the Rico: Adler’s Antique Typewriters, From Creed to QWERTY, and Dingwerth’s Kleines Lexikon Historischer Schreibmaschinen.
Adler calls it a “pleasant toy typewriter with indicator selecting letters from a rectangular index”, saying nothing more descriptive. Dingwerth’s volume both dates the Rico and lists the maker as Richard Koch & Co. of Nuremburg.
The Rico was ambitiously declared the No. A1 model, though there is no evidence of any other model in existence. It was made mostly of stamped tin, though the type element was made of brass. The type element looked like a tube cut in half lengthwise, and worked in a similar fashion to the Chicago typewriter with its type sleeve.
There are some interesting things about the Rico nonetheless. The platen could not accommodate paper wider than 4″, for one thing. There is also no inking system to speak of. Weirder still, this oversight isn’t mentioned in the original instructions. Most people just taped a couple inches of typewriter ribbon between the element and the platen and called it good .
To use the thing, you would move the center lever to the character you wanted. The lever has a pin in the bottom, and each character has a dimple in it for the pin to sit. The lever on the left side was used to pivot the carriage toward the type element in order to print. In total, the Rico typed 74 characters plus Space.
Once upon a time, New Jersey high schooler Umang Sharma saw an ad for a Braille keyboard. The price? A cool seven grand. For a keyboard. No problem, he thought. I can build my own.
The astute among you will notice that there’s a Logitech keyboard in the picture, with what look like key cap hats. That is exactly what’s happening here. Sharma starts with a standard keyboard base, one that is usually either donated or was previously discarded.
He then focuses on the most important accessibility layer, which is tactile Braille key caps that are both readable and durable. In 2022, Sharma launched the non-profit Jdable to bring affordable, accessible design to people with disabilities.
He designed the key caps himself, and uses a combination of 3D printing and other materials to create them in bulk. They’re printed using a combination of PETG for toughness, TPU for grippiness, and resin for definition. The key caps are attached to the standard set with a strong adhesive.
Sharma has a team of student volunteers that help him build the keyboards and distribute them, and they have reached nearly 1,000 blind or visually-impaired students in the U.S. and abroad.
Got a hot tip that has like, anything to do with keyboards? Help me out by sending in a link or two. Don’t want all the Hackaday scribes to see it? Feel free to email me directly.
2026-03-06 00:30:44
Vibe coding is all the rage at the moment if you follow certain parts of the Internet. It’s very easy to dunk upon it, whether it’s to mock the sea of people who’ve drunk the Kool-Aid and want the magic machine to make them a million dollar app with no work, or the vibe coded web apps with security holes you could drive a bus through.
But AI-assisted coding is now a thing that will stick around whether you like it or not, and there are many who want to dip a toe in the water to see what the fuss is about. For those who don’t quite trust the magic machines in their inner sanctum, [jscottmiller] is here with Clix, a bootable live Linux environment which puts Claude Code safely in a sandbox away from your family silver.
Physically it’s a NixOS live USB image with the Sway tiling Wayland compositor, and as he puts it: “Claude Code ready to go”. It has a shared partition for swapping files with Windows or macOS machines, and it’s persistent. The AI side of it has permissive settings, which means the mechanical overlord can reach parts of the OS you wouldn’t normally let it anywhere near; the point of having it in a live environment in the first place.
We can see the attraction of using an environment such as this one for experimenting without commitment, but we’d be interested to hear your views in the comments. It’s about a year since we asked you all about vibe coding, has the art moved forward in that time?
2026-03-05 23:00:45
In the 1970s, the USSR had an undersea cable connecting a major naval base at Petropavlovsk to the Pacific Fleet headquarters at Vladivostok. The cable traversed the Sea of Okhotsk, which, at the time, the USSR claimed. It was off limits to foreign vessels, heavily patrolled, and laced with detection devices. How much more secure could it be? Against the US Navy, apparently not very secure at all. For about a decade starting in 1972, the Navy delivered tapes of all the traffic on the cable to the NSA.
You need a few things to make this a success. First, you need a stealthy submarine. The Navy had the USS Halibut, which has a strange history. You also need some sort of undetectable listening device that can operate on the ocean floor. You also need a crew that is sworn to secrecy.
That last part was hard to manage. It takes a lot of people to mount a secret operation to the other side of the globe, so they came up with a cover story: officially, the Halibut was in Okhotsk to recover parts of a Soviet weapon for analysis. Only a few people knew the real mission. The whole operation was known as Operation Ivy Bell.
The Halibut is possibly the strangest submarine ever. It started life destined to be a diesel sub. However, before it launched in 1959, it had been converted to nuclear power. In fact, the sub was the first designed to launch guided missiles and was the first sub to successfully launch a guided missile, although it had to surface to launch.
Oddly enough, the sub carried nuclear cruise missiles and its specific target, should the world go to a nuclear war, was the Soviet naval base at Petropavolvsk.
By 1965, the sub had been replaced for missile duty by newer submarines. It was tapped to be converted for “special operations.” Under the guise of being a deep-sea recovery vehicle, the Halibut received skids to settle on the seabed, side thrusters, specialized anchors, and a host of electronic equipment, including “the Fish” a 12-foot-long array of cameras, sonar, and strobe lights weighing nearly two tons. The “rescue vehicle” on its stern didn’t actually detach. It was a compartment for deploying saturation divers.
An early mission was Operation Sand Dollar. Halibut found the wreck of the Soviet K-129, which the US would go on to recover in another top secret mission, looking for secrets and Soviet technology.
When it came time to deploy the listening device on an underwater cable, Halibut was perfect. It could park a safe distance away, deploy saturation divers, and recover them. If you want to see more about the Halibut, check out the [Defence Central] video below.
This wasn’t a hidden microphone in a briefcase. It was a 20-foot, six-ton pressure vessel parked on the ocean floor. Details are murky, but there was another part, probably smaller, that clamped around the cable. Working inductively, it didn’t pierce the cable for fear the Soviets would notice that. In addition, if they raised the cable for maintenance, the device was made to break away and sink to the bottom.
Needless to say, tapping a cable on the ocean floor isn’t easy. First, they had to locate the cable. Luckily, there were signs at either end telling fishing vessels to avoid the area. That helped, but they still had to search for the 5-inch wide cables. They found them at least 400 feet below the surface, some 120 miles offshore.
Saturation diving was a relatively new idea at the time, and the Navy’s SeaLab experiments had given them several years of experience with the technology. While commercial saturation dives started in 1965, it was still exotic technology in 1971. The first mission simply recorded a bit of data on the submarine and returned it. Once it was proven, the sub returned with the giant tap device and installed it.
It took four divers to position the big tap. Even then, you couldn’t just leave it there. The device used tapes and required service once a month. So Halibut or another sub had to visit each month to swap tapes out. We couldn’t find out what the power source for the bug was, so they probably had to change the batteries, too.
The Soviets didn’t consider the cable to be at risk for eavesdropping, so much of the traffic on the cable was in the clear. It was a gold mine of intelligence information, and many credit the information gained as crucial to closing the SALT II treaty talks.
Most of the crews participating in Operation Ivy Bell didn’t have clearance to know what was going on. Instead, they thought they were on a different secret mission to retrieve debris from Soviet anti-ship missiles.
To keep the story believable, the crew actually did recover a large number of parts from the subject Soviet missiles. Turns out, analysis of the debris did reveal some useful information, so two spy missions for the price of one.
Presumably, the assumption would be that if the Soviets heard a sub was scavenging missile parts, it might qualify as a secret, but it would hardly be a surprise. They couldn’t have imagined the real purpose of the submarine.
Later undersea taps were created that used radioisotope batteries and could store a year’s data between visits that tapped other Soviet phone lines. Submarines Parche, Richard B. Russel, and Seawolf saw duty with some of these other taps as well as taking over for Halibut when it retired four years after the start of Operation Ivy Bell.
The original Okhotsk tap would have operated for many more years if it were not for [Ronald Pelton]. A former NSA employee, he found himself bankrupt over $65,000 of debt. In 1980, he showed up at the Soviet embassy in Washington and offered to sell what he knew.
He knew a number of things, including what was going on with Operation Ivy Bells. That data netted him $5,000 and, overall, he got about $35,000 or so. Oh, he also got life in prison when, in 1985, a Soviet defector revealed he had been the initial contact for [Pelton].
The Soviets didn’t immediately act on [Pelton’s] intel, but by 1981, the Americans knew something was up. A small fleet of ships was parked right over the device. The USS Parche was sent to retrieve it, but they couldn’t find it. Today, it (or, perhaps, a replica) is in the Great Patriotic War Museum in Moscow.
A surprising amount of the Cold War was waged under the sea. Not to mention in the air.
2026-03-05 20:00:38
![The LEGO-lookalike displaying [Paul]'s dashboard](https://hackaday.com/wp-content/uploads/2026/03/Screenshot-2026-03-04-at-14-08-38-Watt-IV-%E2%80%93-the-M2x2.png?w=800)
There’s just something delightful about scaled items. Big things shrunk down, like LEGO’s teeny tiny terminal brick? Delightful. Taking that terminal brick and scaling it back to a full-sized computer? Even better. That’s what designer [Paul Staal] has done with his M2x2 project.
In spite of the name, it actually has a Mac Mini M4 as its powerful beating heart. An M2 might have been more on-brand, but it’s probably a case of wanting the most horsepower possible in what [Paul] apparently uses as his main workstation these days. The build itself is simple, but has some great design details. As you probably expected, the case is 3D printed. You may not have expected that he can use the left stud as a volume control, thanks to an IKEA Symfonisk remote hidden beneath. The right stud comes off to allow access to a wireless charger.
The 7″ screen can display anything, but [Paul] mostly uses it either for a custom home assistant dashboard, or to display an equalizer, both loosely styled after ‘screen’ on the original brick. We have to admit, as cool as it looked with the minifigs back in the day, that sharp angle to the screen isn’t exactly ergonomic for humans.
Perhaps the best detail was putting LEGO-compatible studs on top of the 10:1 scaled up studs, so the brick that inspired the project can sit securely atop its scion. [Paul] has provided a detailed build guide and the STLs necessary to print off a brick, should anyone want to put one of these nostalgic machines on their own desk.
We’ve covered the LEGO computer brick before, but going the other way–putting a microcontroller and display in the brick it to run DOOM. We’ve also seen it scaled up before, but that project was a bit more modest in size and computing power.
