Mysterious Files PH

If you’ve watched a Saturn V launch, you’ve probably seen how a large rocket will often jettison a stage on the way up. There are several reasons for this — there is no reason to haul an empty fuel container, for example. However, you can probably imagine how the separation works. You release something — probably explosive bolts — and gravity pulls the old stage away from you as you climb on the next stage’s engines. But what about on the way back? The command module drops the service module before reentry. [Apollo11Space] has a video explaining just how complicated that was to pull off. You can watch it below.

The main problem? The service module has almost everything you need: oxygen, a big engine, fuel, and electrical generation capability. If you’ve ever seen a real command module, they are tiny. Somehow, you need to get the command module prepared to be on its own for the amount of time it takes to land, and get the service module safely away.

In orbit, gravity isn’t a big help in pulling the two pieces apart. For that reason, the mission design called for a very specific orientation for the separation. There are a number of other details you might not have known about.

Landing Apollo 11 successfully depended on some spy tech. We imagine the separation of the LEM had some similar issues, although even the moon’s weak gravity would have helped.

If you’ve been interested in FreeCAD but haven’t known where to start, here’s a wonderful video tutorial for FreeCAD 1.1 by [Deltahedra] aimed squarely at how to model a 3D part from scratch while also following best engineering practices for part design. It focuses on a concise and meaningful workflow that respects your time and doesn’t make assumptions about skill level. It even starts by taking a few moments to explain how to navigate the interface, a courtesy many will appreciate.

FreeCAD can do quite a lot, so a tutorial that focuses on a specific yet broadly-applicable task with a clear context is a great way to narrow the scope into something manageable, and be comprehensive without getting bogged down in minutiae. [Deltahedra] does this by exclusively using the part design workbench, demonstrating what to do to make a part step-by-step, and showing common mistakes that can happen and how to fix them if they occur. Beyond that, it’s left up to the curious hacker to delve for themselves into what else FreeCAD has to offer.

Since 1.1 is (at this writing) the latest stable release, one can also be confident that the tutorial will match the user interface and features one sees on their own screen. After all, it can be frustrating to attempt to follow a tutorial only to find out things are a few versions behind and nothing is where one expects it to be.

Best practices aren’t just fussy rules about how to do things, and [Deltahedra] demonstrates this by showing how certain procedures just plain make more sense when designing shapes. Our own Arya Voronova has also shared best practices for FreeCAD, so check that out for some added perspective. You’ll be wielding FreeCAD in confidence and comfort in no time.

Thanks for the tip, [Vik Olliver]!

As time marches on, the retro gaming community gets more and more access to older systems. This is partially a product of modern computing having much more power to emulate more demanding systems, but also because many in the community have spent more time with their favorite systems. Such is the case for [tschicki] who has spent considerable time and effort reverse engineering the Playstation 2 to come up with this custom mainboard for a handheld version that still uses some of the original chips from the console.

This Playstation 2 handheld console is designed almost completely from the ground up, not just including the impressive main board but also its modernized features, including USB power delivery handled by an RP2040, digital video output, support for modern storage media like SD cards, a customized boot ROM, and upgraded audio. The DualShock 2 controller is also implemented within the handheld, and the case itself is designed to be 3D printed. It’s an impressive effort which preserves the original feel of the console without relying too much on ancient hardware for everything.

Before jumping in to building one yourself, though, [tschicki] cautions that this project is not for the faint of heart, as it requires some specilized tools and a high degree of skill, but for those still wishing to attempt this build all of the instructions are available on the project site. For such a popular console it’s no surprise we’ve seen plenty of other handheld PS2s before, from this one which uses an original PS2 mainboard to this one we featured way back in 2010.

Thanks to [raz] for the tip!

Along with Velcro, zippers have become an integral part of every day life, being a quick and easy way to usually temporarily join fabric together. Which isn’t to say that you cannot do more with the basic zipper concept, including using them to turn floppy 2D shapes into rigid 3D ones, such as with the Y-zipper concept proposed and demonstrated by [Jiaji Li] et al.

Although not a fully new idea, the Y-zipper is compared with a range of similar mechanisms that do not feature the same abilities, including the standard zipper ease of zipping up, the possibility of having curved geometry and automatic actuation.

Plus there is that the Y-zipper is designed from the start to be 3Dprinted, while still following the same basic pattern of interlocking teeth that the slider mechanism alternately pushes together or pulls apart.

By modifying the basic straight design of the flat strips, the resulting zipped-up form can take on a distinct bend, as well as turn into a coil or a screw. With a demonstrated joint design it is then possible to join multiple Y-zipper rods together, which could make for an interesting alternative to traditional pop-up tent supports, for example.

Also demonstrated is the use of TPU to create compliant bridges, as well as the direct integration of fabric, to show the versatility of the technology. With the used materials (PLA, TPU) the researchers estimate a maximum viable length of about 3 meters before the printed structures begin to disintegrate.

In the search for more exciting broken electronics to repair, [Hugh Jeffreys] bought a GoPro Hero 10 for US$100 with an apparently rather common issue of no camera input, along with a cracked display. This particular camera issue is rather obvious, with just darkness where the camera’s input should appear on the display. Since [Hugh] already needed a spare display, he figured that he might as well get an even more broken GoPro Hero 10 for parts.

Another US$40 later, [Hugh] found himself the proud owner of a second GoPro, this one being water damaged and no longer turning on. Getting to the internals requires removing the glued-in display, which is even trickier than with a smartphone. By inserting a thin blade, adding solvents and not prying, you can slowly work it loose.

With two disassembled GoPros it was now possible to swap modules. After a factory reset and firmware update had failed to fix the first GoPro, the camera module from the donor unit was inserted, but this made no difference. Amusingly, after cleaning the water-damaged unit’s PCBs, it was found to be in good working condition, so ultimately the second GoPro was repaired, leaving the ‘no camera input’ issue undiagnosed.

It’s possible that a board-level repair on the first unit can address the original issue, but without schematics this would likely entail a lot of blindly poking around, in the hope of finding a damaged MLCC or other obvious fault. There is also the possibility that this is a firmware issue, with some reporting luck mashing the report button, but others disagree.

Since [Hugh] did do the firmware reset and updating steps, and even inserted a whole new working camera module, it would seem to narrow the problem down to a board-level issue. Whatever the case may be, it’s a frustrating issue with a rather expensive device.

Aside from nostalgia, people claim to like CRTs because they’re apprehendable– the technology just makes more sense than the arcane wibbly-wobbly solid-state madness going on inside the driver chip of your new OLED. CRTs weren’t the first technology used to display moving images though, and their mechanical forebears were even easier to understand. For that reason we suppose it was only a matter of time before one of The Youths– in this case a British YouTuber by the name of [smill]–tried gaming on a mechanical television display.

The game in question was Minecraft— because of course it was, that’s the new generation’s DOOM–and the mechanical TV in question is not a priceless 1920s antique but a commercial kit that reproduces [John Logie Baird]s 1925 televisor. If you’re not familiar, it uses a flat disk– called a Nipkow disk after its inventor– with a series of holes in a spiral to demodulate a single lamp’s brightness variations into monochrome image made of scan-lines. As you might imagine, the resolution depends both on the size of the disk and its speed, so with a tabletop example you’re not going to get much– in this case, 32 holes for 32 lines. At least they’re not interlaced this time.

Getting a video signal from the computer to the LED in the televisor kit was the hard part of the hack. Aside from actually playing on the diminutive monochrome display, that is. There is a “video2NBTV” tool that can do the job, as the Narrow Band TV signal used by amateur radio enthusiasts still has the compatible timing values and modulation as what the televisor kit uses. We suspect that’s because the Televisor people used the modern NBTV standard as a starting point for their electronics, since [Baird]’s device reportedly ran 30 lines at only 5 frames per second, compared to the 32 lines at 15 FPS here.

Some of you may turn your nose up at this as a mere YouTube stunt, which is fair enough. At the same time, we cannot wait for the eventual arms race. Imagine when someone decides to go for 4K cred? Staring through a supersonic Nipkow disk makes pointing a particle accelerator at your face downright mundane. The kit [smill] used was monochrome, but if you want to repeat his antics in glorious colour, you can 3D print your own TV.

In the time Hackaday has been in existence we must have brought you plenty of projects housed in Altoids tins, as well as a sizeable number of cyberdecks. But until today with [Exercising Ingenuity]’s build, we’ve never brought you a project that combines the two. It’s a fully functional computer that runs Linux, and with its Altoids tin enclosure, looks for all the world like a miniature clamshell laptop.

Hardware wise it’s a Pi Zero with a UPS PHAT and an SPI display, but perhaps it’s arguably the home-made keyboard that really sets it apart. There’s a full-size USB port as well, and a selection of GPIOs are broken out to a header. It wasn’t all plain sailing though, the Altoids hinges needed modifying to make it close, and he driver for the SPI screen required an older version of Raspberry Pi OS. We will forgive it those foibles.

It’s fair to say we’ve not seen anything quite like this, in that there have been plenty of tiny laptops but never one as integrated as this. There’s a demo video with details of the build, that we’ve placed below.