TechyMagThings

We notice there are a lot of hacks on YouTube lately, but we don’t share enough hacks about YouTube. That’s why [PortalRunner]’s latest oeuvre is interesting: it’s a video that gives you a different picture depending on the selected bitrate.

Watch it at 1080p, you get one thing; at 360p, the image is completely different. The hack relies on understanding precisely how YouTube cuts down videos — because if you haven’t uploaded a video there before, you might not know the creator doesn’t have to encode all of those options; they’re invited to upload in the highest possible definition, and YouTube reencodes the rest.

1080p and 720p films are shown at 60FPS, while 360p and below are 30FPS– so that’s one way to hide the difference. Since YouTube drops every second frame when encoding the lower-quality video, images you want in the HD version can be kept only in even-numbered frames that YouTube will remove. That seems easy enough, but how does [PortalRunner] avoid the low-quality image flickering in at 30 FPS when watching in higher definition?

Well, that relies on understanding exactly how downsampling works: going from 1080p to 360p means tossing out every third pixel in both the horizontal and vertical directions. If you’re careful, it turns out you can craft an image that vanishes when the 3×3 grid of pixels it’s made of at 1080p is averaged to a single background-colored pixel at 360p. [Portal Runner] is using vertical stripes here, but that’s not the only way to do it. Just to be sure the message came through loud and clear at 1080p, though, the original image, not the stripy one, is used on the odd-numbered, discarded frames.

Hiding the 1080p video is only half the battle: he needs to get those frames not to average specifically to the background color, but to make his new images. That’s a bit tricky, which is why the demonstration uses “1080p” and “lower” as its easter eggs: they fit well inside one another, with the characters lining up one-to-one. That’s without even getting into the hack he’s using with extra i-frames to create thumbnails on the timeline to tell you to ‘subscribe’. Look, it is YouTube, what else can you expect?  We’re just glad to see a totally benign hack of the platform that’s holding so many hacks these days.

Of course, real hackers live on the command line, and you can play YouTube there, too.

For as many speakers as someone can cram into a surround sound system, humans still (generally) only have two ears to listen to those sounds with. This means that, for recording purposes, it’s possible to create incredibly vivid three-dimensional sounds with just two microphones, provided that there’s an actual physical replica of a human ear attached to each microphone. This helps ensure that all the qualities of the sounds are preserved in a way a real human would experience them, and as [David Green] demonstrates, these systems don’t need to be very expensive.

This build doesn’t just use models of human ears for recording sounds through. The silicone ears are mounted on a styrofoam mannequin head as well, which provides some sound isolation between the two microphones, much like a real human head. The ears are mounted in appropriate locations with the microphones installed inside, and the entire microphone apparatus is positioned on a PVC rig with a camera so that binaural audio will be recorded for anything [David] points it at.

Although he had some issues interfacing two microphones using 19th-century technology instead of soldering everything together, the build still eventually came together, and only for around $70 USD. However, this build is a bit dated now, so prices may have changed by now. It’s still a great way to produce realistic stereo sound without breaking the bank, but it’s not the only way of getting this job done.

While Artemis II was primarily a demonstration flight of the architecture NASA plans to use for future lunar missions, it was also an excellent excuse for the crew to snap some photos of the Moon and Earth with the benefit of modern camera technology. If you’ve been looking forward to seeing more of the crew’s images, you’re in luck, as thousands of new images have recently been released.

Now we don’t mean to beat up on the folks at NASA, but browsing through these images, we couldn’t help but be reminded of an article we saw on PetaPixel that discussed the space agency’s haphazard approach to sharing images online.

It’s really more like an unsorted file dump than anything, made worse by the fact that you have to access it through a government website that looks and performs like it was designed in the early 2000s. There’s even a prominent button that attempts to load a gallery feature that relies on the long-deprecated Adobe Flash. It would be nice to see the situation improved by the time astronauts actually touch down on the lunar surface, but we wouldn’t count on it.

Speaking of old tech, we’ve been following the resurgence of keyboard-equipped smartphones with great interest, as we imagine many of you have been. A recent CNBC article addresses the trend, although it didn’t quite take the nerd contingent into account. We want physical keys so we can work in the terminal and write code without fighting an on-screen keyboard, but of course, that’s not exactly what your average consumer is looking for.

It’s quite the opposite, in fact. A 20-something user referenced in the article explained how the younger generations see the physical keyboard as a way to be less connected to their phones, describing it as “an extra barrier of inconvenience that adds more steps into the thinking process.” If you need us, we’ll be collecting dust in the corner.

As regular readers may know, we’ve also taken an interest in plug-in solar panels recently. So-called “solar balconies” have become quite popular in Europe, but regulatory friction in the United States has prevented them from achieving similar success here. An article in the MIT Technology Review talks about the process of bringing solar balconies to the US, and we’re not overly thrilled with some of the developments it highlights.

As the key hurdle appears to be safety, UL Solutions recommends that balcony solar panels be plugged into a specialized outlet. If putting a regular AC plug on the end of a solar panel can lead to potentially dangerous situations, they believe the solution is to require a different plug that no one could mistake for anything else, with built-in safety features to reduce the risk of electric shock.

That might not seem unreasonable at first, but it actually represents a pretty serious hurdle for many users. Consider that the whole advantage of these panels is the convenience: you can simply open the box, plug them in, and start collecting energy. But if you need to install a special outlet, potentially requiring an electrician, the whole concept falls apart. Expect to hear more from us on this particular subject as it develops.

Finally, Spirit Airline customers weren’t the only ones running into issues this week — a Southwest flight in California was delayed due to complications with a robotic passenger. The bot actually had a ticket, but the flight crew said it still violated the airline’s rules for large carry-on luggage and had to be moved to a different seat. Then somebody realized the robot’s relatively large lithium-ion battery was also in violation of carry-on limits, and it had to be removed and confiscated by authorities. Important details to keep in mind if you happen to be a robot planning your summer vacation.

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.

The idea of using cardboard for a sloppy PC case isn’t new; it’s a time-honored tradition dating back to at least the 1990s. That said, with today’s CNC cutters and other advanced tooling available to hobbyists, you might be curious to see how far you can push the concept. As demonstrated in a recent video by [mryeester], the answer appears to be that good planning and a solid understanding of cardboard’s limitations are as essential as ever.

After having the PC case drawn up in CAD and cut on a professional CNC cutter by a buddy who makes commercial cardboard displays, the installation procedure for the PC components showed where a bit of foresight could have saved a lot of time and effort.

The first problem was that the GPU couldn’t be installed due to wrong measurements on where the IO bracket normally is screwed into the case. Some cardboard cutting later, the GPU slid into place, but of course, there’s no way to screw it down, putting the full weight on the PCIe slot of the mainboard. Fortunately, the mainboard was quite literally bolted into place, and the case consists of multiple layers of corrugated cardboard to add some rigidity.

Next was more carving as the PSU cut-out was designed for an SFX PSU, not an ATX one. After that ordeal, one could say that perhaps a nice thing about a cardboard case is that you get to pick where buttons are located, though this comes with its own logistical issues.

Finally, mounting side panels turned into another chore, with perhaps some engineering possible to make it work better. For example, we recently looked at making cardboard hinges that would look pretty good on a cardboard PC case. You can also waterproof cardboard and make it much stronger, turning a throwaway, temporary cardboard solution into something that will last for years, even with occasional exposure to moisture and a water-cooling leak.

The bicycle is an invention that has not changed in its fundamentals since the first recognisably modern machines appeared in the closing years of the 19th century. Its frame uses a structure of two triangles, its wheels are equal in size, and it’s propelled by a pedal crank and (in most cases) a chain. Bicycles have improved vastly in materials and performance, but if you were to wheel a 2026 tourer into an 1886 bike shop, the Victorian proprietor would recognise it. Only a very brave engineer would try to fundamentally change such a formula, but here’s [Not programming] with a crankless bicycle.

The idea is to replace the crank’s circular motion with a linear one, thus providing a more constant propulsion. The build was inspired by another that used a sinusoidal track in a rotating cylinder to achieve the necessary conversion. This design takes a different tack, using an arrangement of gears and freewheels he describes as a mechanical rectifier to convert the back-and-forth motion of pedaling into rotation. The pedals themselves are stirrups mounted at each end of a V-belt.

This build is an exercise in pushing the limits of 3D print strength, as prototype after prototype shears under load. He does finally get the thing to work, though, and we admire his persistence. Oddly, this isn’t the first 3D-printed bicycle geartrain we’ve seen.

CDMA2000 was one of the protocols defined for 3G networks and is now years out of date and being phased out worldwide. Nevertheless, there are still vast numbers of phones that will happily connect to it, creating an opportunity for hackers seeking to run their own cellular networks. [Chrismoos] recently made this endeavour significantly easier by releasing 1xBTS, a Rust implementation of the lower three layers of a CDMA2000 network.

The lowest layer of the stack is an SDR for the actual radio communications. It’s been tested with the USRP B200 and B210, the LimeSDR Mini 2, and the BladeRF Micro 2.0. The code might work with certain other SDRs using the SoapySDR abstraction layer. The SDR is controlled by the base station (BTS) software, which, in turn, is controlled by the base station controller (BSC) over an Abis link. The BSC manages channels and mobile device associations, and exchanges frames with the mobile switching center (MSC), which handles message switching.

The stack includes standard 3G verification; before a handset can authenticate to the network, its details must be added to the home location register (HLR). Once authenticated, the handset can access all standard services: inbound and outbound voice calls via a SIP gateway, inbound and outbound SMS, and data packet transfers. A web dashboard provides a convenient management platform that includes packet tracing.

It should be noted that using this carelessly is legally hazardous; radio transmissions are strictly regulated in most countries, particularly in the cellular bands. If you’d still like to run your own cell network, we’ve also seen a few other efforts, such as this 4G implementation, this 1G recreation, and a GSM network made for a hacker camp.

After Noctua recently released CAD files for a range of their computer fans, one of the first thoughts that popped up for most people was: Can you just to 3D print their fans? Even though Noctua begs you not to 3D print the files and even says they changed the design slightly so it wouldn’t be the same anyway, the question persists. Fortunately, [Steve] of Gamers Nexus is here to help us answer the question of whether it makes sense to 3D print a computer fan.

Unsurprisingly, the answer is mostly a resounding ‘no’. After reworking the original CAD models to be both printable on a Bambu Lab FDM printer and printing the parts in PLA, the arguably most important part, the motor, still had to be sourced from an original Noctua fan. Although you could source a cheaper motor, that could change the fan’s characteristics.

The other issue is materials. The special polymer that Noctua uses for its fans is designed not to change shape significantly when the fan blades are spinning, whereas PLA and basically every other thermoplastic will likely deform enough to hit the inside of the fan with the blades. For this reason, a 3 mm gap was used in the PLA print compared with the approximately 0.5 mm gap of the original Noctua fan.

Using the professional fan tester and semi-anechoic chamber over at Gamers Nexus, the original and replica fans were compared, showing that the 3D-printed fan had a similar noise profile but produced only about half the airflow. This is likely due to the blade shape and angle, the increased gap, and probably a dozen other details that presumably justify putting a cool $40 down for the original fan.

In short, you’re probably best off using these Noctua fan CAD models for fit testing in a larger CAD model, or 3D printing it for a similar purpose, rather than for a functional fan design. At least now we know. Thanks, [Steve].