Reviving Google Cardboard, Without Google Or Cardboard

Remember Google Cardboard? The late, unlamented practice of strapping a phone to your face so you could get motion sickness in a virtual environment? [brenpoly] wants you to reconsider, because in the years since Google pulled the plug on mobile VR, phones have gotten really, really good and he’s got a project called CardboardXR on GitHub that the project video enbedded below bills as “A 5$ Apple Vision Pro”

Well, it’s 5$ if you already happen to have a flagship phone like the Pixel 9 Pro or iPhone 15 Pro he’s using for testing– otherwise you’d be out a rather larger chunk of change in order to pick up such a pocket supercomputer. In any case, he’s able to get 6 Degree of Freedom (DOF) tracking from these units, along with using the cameras for passthrough and object detection, hand tracking, and gesture control– everything the big boys net you, in other words. That’s pretty impressive compared to the 3DOF, and zero tracking or pass-through mobile VR used to get you.

He’s also built adjustable optics into his 3D-printed replacement for Google’s old face-hugging cardboard, which you can get on Makerworld.  On the other hand, presumably you could just cut a hole for the camera bumps in one of those if you’re the kind of person who throws nothing out. Either way you’d be using the same lenses; it turns out they’re still available online, so that’s what [brenpoly] spec’d.

All these fancy features aren’t entirely [brenpoly]’s own work: his software is based on Unity which has some slick VR/AR tools and the ability to build in all the relevant machine learning models for things like hand tracking. He’s also taking some major inspiration from the Google Cardboard SDK, which Google open-sourced back around the time they gave up on it. It’s still a very impressive project regardless of the toolchain involved, though there’s a certain irony that [brenpoly] is now strapping a phone to his face after his last project we featured  was all about getting him to put it down.

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Stunning Volumetric 3D Display Goes For A Spin

[AncientJames] gives us a detailed look at Vortex, one of his impressive volumetric displays made with two back-to-back LED panels that spin at high speed with a Raspberry Pi 4 driving it all. Vortex generates a true 3D image hanging in space that one can move around, and look at from different angles independent of anything else. The software for Vortex is up on GitHub which includes a simulator as well as CAD models for the 3D-printed parts.

The images move, but can also be viewed from any angle.

Accomplishing what Vortex does requires precisely matching the images rendered on the panels to the physical rotation. If there’s a mismatch, the displayed 3D image will drift, or appear distorted. There’s also the physical matter of ensuring the spinning elements are balanced and stable while spinning at high speeds, a nontrivial undertaking that involved more than a little trial and error.

The amazing build quality and attention to detail really shines through, not just with the design but with smart use of off-the-shelf items like a large plastic globe for the display cover. [AncientJames] uses what looks like a plastic globe shade meant for a lighting fixture, and designs a clever fixture that attaches to a small rotary tool with a cutting wheel. With that, he can carefully and precisely cut away the unneeded section. Here’s a link to him doing so (at the 15:17 mark) in the video; sometimes it’s worth making a one-off gadget if it helps get a job done right.

[AncientJames] has made many volumetric displays in the past, and they’re each a little different. Check out one that spins a perforated drum around LED panels to create a lightfield display, instead of spinning the panels themselves.

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A Tiny OS For A Tiny Board

As microntrollers have become ever more powerful, we have started to see an increasing number of operating systems written to take advantage of this extra power. Usually they’re aimed at handheld or other similar devices with support for screens and input devices, but just what can be done if a developer eschews those niceties? KoaOS is a small OS for the ESP32-S3 on the Heltec WiFi LoRa 32 V4, and it’s headless. You can only talk to it via a serial terminal on its USB port.

What it provides is a UNIX-like shell, with editor, GPS, weather and APRS apps ready to run. It’s not just limited to those, there’s an SDK of sorts to create new apps and compile them from C. These .esp files can be installed and uninstalled at will over the network.

There are a few limitations, for example it’s only for the Heltec V4 due to a large requirement for PSRAM. We are guessing that another similar spec board could probably be made to perform, however it’s clear that hasn’t yet been done. Despite that we think this OS is interesting for concentrating on the OS rather than the interface, and we hope to see it develop further.

Several takes on an ESP32 OS have appeared in recent times, including this JavaScript one.

Folding Wings Could Be The Future For Air Travel

Folding wings have a long history in aviation. Particularly in the military world, where the ability to fit more fighting planes on a boat made a very real difference to the outcomes of a combat situation. In civil aviation, though, particularly at commercial scales, the idea has been less popular.

As unattractive as complexity can be, the push for ever greater efficiency and performance may be changing things in this space. In coming years, you might find yourself boarding an airliner and watching the wings fold out prior to take off, in a way that once unthinkable for a conventional commercial aircraft.

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Pitting A Modern Chess Engine On A Pentium PC Against 1996’s Deep Blue

Although premature optimization can be a really bad thing, late optimization is sometimes unavoidable because we simply didn’t know about certain algorithms yet to massively improve the solving of a problem. When the 1990s was all about beating chess grandmasters at their game, IBM went so far as to build a the Deep Blue custom super computer for it. This is what [Nicholas Carlini] managed to effectively beat using a version of the Stockfish chess engine running on an era-appropriate Pentium PC.

A common way to measure one’s skill in chess involves the Elo rating system, named after chess master and physics professor [Arpad Elo]. As a relative system, it can be used to compare different players including chess engines against each other, with IBM’s Deep Blue scoring 2700, with the modern-day Stockfish engine hitting around 3700. This makes Stockfish statistically much more likely to win against a human chess grandmaster than Deep Blue, but also raises the question of how much of this advantage is due to Stockfish running on a much faster system.

To investigate the impact here, [Nicholas] used a Pentium Pro 200 MHz system with 64 MB of RAM (Fast Page or EDO SIMMs), which would have been a rather nice system for about 1995. Two chess engines were ported to this platform, being Crafty and Stockfish. Next both engines were tweaked with the help of an LLM coding bot to see what difference various compilation flags and algorithms would make.

Based on the results it would seem that the answer is ‘yes’: this 200 MHz Pentium Pro could have likely beaten even a chess grandmaster like [Kasparov] and Deep Blue in at least a few games, though without going back in time by about thirty years we’ll never know for certain.

Header: Wilfredor, CC0

I Think We Should See Other SBCs

Are you currently designing a project for a common single-board computer (SBC), and do you expect other people to build your project, too? We routinely feature projects that do exactly this. Well, turns out SBC availability is a problem now – and I’d like to teach you how to pick SBC alternatives, mostly to the Raspberry Pi boards.

We had SBC shortages before, but 2026 has beat them all, and it doesn’t look like it’ll stop within even a few months. RAM prices have incinerated the supply side of single-board computer availability, and I suspect that consumer SBC use in Russian drones had a noticeable impact, too.

Less-utilized SBCs always brought their own advantages to the table. If you didn’t like that the Pi Zero came with only 512MB of RAM, you could always buy an Orange Pi or a Radxa board with 2GB or 4GB for a meager increase in price. Now, there’s even more of a motivation to explore what’s on offer!

This year, SBC prices and availability have both jumped up tremendously, and even the Zero 2W stocks have evaporated. Me, I had to make a few of my projects way more flexible way quicker. Now, I have some experience to share!

Finding Your New SBC Friends

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Finger Joint Cutter Uses A Jigsaw Blade, But Not As We Know It

Around these parts, finger joints (or box joints) are usually the product of laser cutting. [bluesyann] shows us a method of using a stationary jigsaw, a custom blade, and 3D-printed jig to create a DIY box joint cutter whose results look impressive. What’s appealing is not just the end result, but the fact that the whole system is made from little more than an inexpensive tool, scrap wood, and common hardware.

A DIY wide blade cuts each notch in a single go.

In [bluesyann]’s system, the jigsaw is fixed in place to make a stationary cutter. The saw itself is nothing special; it’s the wide blade that makes the difference. It cuts a notch in a single go, and it’s made by epoxying together multiple blades to make a single extra-wide one. Jigsaw blades are not expensive, and they’re easy to snap into pieces. By using a total of three blades (snapping two of them into pieces) one can create the wide version shown here.

With a stationary jigsaw sporting an extra-wide blade that cuts the same notch every time, all that remains is a way to get the spacing right. The solution there is a 3D-printed jig that each freshly-cut notch fits onto as the next one is cut.

There are a few other details, but those are the important bits. One does have to do a bit of trial and error to get things dialed in, but once they are, it’s off to the races.

If one prefers a less hands-on method of cutting box joints, check out this robotic table saw which automates the process.