TechyMagThings

In theory HDMI’s CEC feature is great, as it gives HDMI devices the ability to do useful things such as turning on multiple HDMI devices with a single remote control. Of course, such a feature will inevitably feature bugs. A case in point is the Nvidia Shield which has often been reported to turn on other HDMI devices that should stay off. After getting ticked off by such issues one time too many, [Matt] decided to implement a network firewall project to prevent his receiver from getting messed with by the Shield.

The project is a Python-based network service that listens for the responsible rogue HDMI-CEC Zone 2 requests and talks with a Denon/Marantz receiver to prevent it from turning on unnecessarily. Of course, when you want these Zone 2 requests to do their thing you need to disable the script.

That said, HDMI-CEC is such a PITA that people keep running into issues like these over and over again, to the point where people are simply disabling the feature altogether. That said, Nvidia did recently release a Shield update that’s claimed to fix CEC issues, so maybe this is one CEC bug down already.

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.

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.

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.

Your education begins with the why, so you can skip that if you must, but the visuals are a nice refresher on that front.

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

Is That a Bat In Your Pocket?

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.

This unibody beauty runs on an RP2040 Zero using QMK firmware. That 40 mm Cirque track pad has a glass overlay, which is a really nice touch. It’s actually a screen protector for a smart watch, and the purple bit is some craft vinyl cut to size.

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.

The Centerfold: [arax20]’s Been Workin’ On the Railroader

Okay, before you do anything, go check out the image gallery to see this baby glowing and being worn like a katana or something. Yeah.

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!

Historical Clackers: the Mysterious Rico

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.

Finally, Someone’s Made a Braille Keyboard, and It’s Inexpensive

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.

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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.

If you were to read the README of the Vib-OS project on GitHub, you’d see it advertised as a Unix-like OS that was written from scratch, runs on ARM64 and x86_64, and comes with a full GUI, networking and even full Doom game support. Unfortunately, what you are seeing there isn’t the beginnings of a new promising OS that might go toe to toe with the likes of Linux or Haiku, but rather a vibe-coded confabulation. Trying to actually use the OS as [tirimid] recently did sends you down a vibe-coded rabbit hole of broken code, more bugs than you can shake a bug zapper at, and most of the promised features being completely absent.

[tirimid] is one of those people who have a bit of a problem, in that they like to try out new OSes, just to see what they’re like. The fun starts with simply making the thing run at all in any virtual machine environment, as apparently the author uses MacOS and there it probably ‘runs fine’.

After this the graphical desktop does in fact load, some applications also open, but it’s not possible to create new folders in the ‘file explorer’, the function keys simply switch between wallpapers, there’s no networking or Doom support despite the promises made, there’s no Python or Nano support at all, and so on.

Clearly it’s still got the hallmarks of a functioning OS, and it’s sort of nice that you don’t need to know what you’re doing to create a sort-of-OS, but it will not appease those who feel that vibe-coding is killing Open Source software.

[Diffraction Limited] has been working on a largely 3D-printed micropositioner for some time now, and previously reached a resolution of about 50 nanometers. There was still room for improvement, though, and his latest iteration improves the linkage arms by embossing tiny ball joints into them.

The micro-manipulator, which we’ve covered before, uses three sets of parallel rod linkages to move a platform. Each end of each rod rotates on a ball joint. In the previous iteration, the parallel rods were made out of hollow brass tubing with internal chamfers on the ends. The small area of contact between the ball and socket created unnecessary friction, and being hollow made the rods less stiff. [Diffraction Limited] wanted to create spherical ball joints, which could retain more lubricant and distribute force more evenly.

The first step was to cut six lengths of solid two-millimeter brass rod and sand them to equal lengths, then chamfer them with a 3D-printed jig and a utility knife blade. Next, they made two centering sleeves to hold small ball bearings at the ends of the rod being worked on, while an anti-buckling sleeve surrounded the rest of the rod. The whole assembly went between the jaws of a pair of digital calipers, which were zeroed. When one of the jaws was tapped with a hammer, the ball bearings pressed into the ends of the brass rod, creating divots. Since the calipers measured the amount of indentation created, they was able to emboss all six rods equally. The mechanism is designed not to transfer force into the calipers, but he still recommends using a dedicated pair.

In testing, the new ball joints had about a tenth the friction of the old joints. They also switched out the original 3D-printed ball mount for one made out of a circuit board, which was more rigid and precisely manufactured. In the final part of the video, he created an admittedly unnecessary, but useful and fun machine to automatically emboss ball joints with a linear rail, stepper motor, and position sensor.

On such a small scale, a physical ball joint is clearly simpler, but on larger scales it’s also possible to make flexures that mimic a ball joint’s behavior.

Disposable vapes aren’t quite the problem/resource stream they once were, with many jurisdictions moving to ban the absurdly wasteful little devices, but there are still a lot of slightly-smelly lithium batteries in the wild. You might be forgiven for thinking that most of them seem to be in [Chris Doel]’s UK workshop, given that he’s now cruising around what has to be the world’s only vape-powered car.

Technically, anyway; some motorheads might object to calling donor vehicle [Chris] starts with a car, but the venerable G-Wiz has four wheels, four seats, lights and a windscreen, so what more do you want? Horsepower in excess of 17 ponies (12.6 kW)? Top speeds in excess of 50 Mph (80 km/h)? Something other than the dead weight of 20-year-old lead-acid batteries? Well, [Chris] at least fixes that last part.

The conversion is amazingly simple: he just straps his 500 disposable vape battery pack into the back seat– the same one that was powering his shop–into the GWiz, and it’s off to the races. Not quickly, mind you, but with 500 lightly-used lithium cells in the back seat, how fast would you want to go? Hopefully the power bank goes back on the wall after the test drive, or he finds a better mounting solution. To [Chris]’s credit, he did renovate his pack with extra support and insulation, and put all the cells in an insulated aluminum box. Still, the low speed has to count as a safety feature at this point.

Charging isn’t fast either, as [Chris] has made the probably-controversial decision to use USB-C. We usually approve of USB-Cing all the things, but a car might be taking things too far, even one with such a comparatively tiny battery. Perhaps his earlier (equally nicotine-soaked) e-bike project would have been a better fit for USB charging.

Thanks to [Vaughna] for the tip!