VR Prototypes Reveal Facebook’s Surprisingly Critical Research Directions

June 26, 2022 by Donald Papp 32 Comments

A short while ago, Tested posted a video all about hands-on time with virtual reality (VR) headset prototypes from Meta (which is to say, Facebook) and there are some genuinely interesting bits in there. The video itself is over an hour long, but if you’re primarily interested in the technical angles and why they matter for VR, read on because we’ll highlight each of the main points of research.

As absurd as it may seem to many of us to have a social network spearheading meaningful VR development, one can’t say they aren’t taking it seriously. It’s also refreshing to see each of the prototypes get showcased by a researcher who is clearly thrilled to talk about their work. The big dream is to figure out what it takes to pass the “visual Turing test”, which means delivering visuals that are on par with that of a physical reality. Some of these critical elements may come as a bit of a surprise, because they go in directions beyond resolution and field-of-view.

Solid-state varifocal lens demo, capable of 32 discrete focal steps.

At 9:35 in on the video, [Douglas Lanman] shows [Norman Chan] how important variable focus is to delivering a good visual experience, followed by a walk-through of all the different prototypes they have used to get that done. Currently, VR headsets display visuals at only one focal plane, but that means that — among other things — bringing a virtual object close to one’s eyes gets blurry. (Incidentally, older people don’t find that part very strange because it is a common side effect of aging.)

The solution is to change focus based on where the user is looking, and [Douglas] shows off all the different ways this has been explored: from motors and actuators that mechanically change the focal length of the display, to a solid-state solution composed of stacked elements that can selectively converge or diverge light based on its polarization. [Doug]’s pride and excitement is palpable, and he really goes into detail on everything.

At the 30:21 mark, [Yang Zhao] explains the importance of higher resolution displays, and talks about lenses and optics as well. Interestingly, the ultra-clear text rendering made possible by a high-resolution display isn’t what ended up capturing [Norman]’s attention the most. When high resolution was combined with variable focus, it was the textures on cushions, the vividness of wall art, and the patterns on walls that [Norman] found he just couldn’t stop exploring.

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Want A Break From Hardware Hacking? Try Bitburner

June 26, 2022 by Al Williams 19 Comments

If you ever mention to a normal person that you’re a hacker, and they might ask you if you can do something nefarious. The media has unfortunately changed the meaning of the word so that most people think hackers are lawless computer geniuses instead of us simple folk who are probably only breaking the laws meant to prevent you from repairing your own electronics. However, if you want a break, you can fully embrace the Hollywood hacker stereotype with Bitburner. Since it is all online, you don’t even have to dig out your hoodie.

The game takes place in 2077 where, apparently, people are still using green monochrome terminals and writing JavaScript code. Who knew? The operating system is suspiciously Linux-like with commands like alias, cat, cp, kill, and the like. We were nonplussed that in 2077 they’re still using vim, but you can use nano. We always thought real hackers would be emacs users. Our machine only starts out with 8 MB of RAM, too. Good thing you can virtually buy more.

We won’t quibble that cls is a synonym for clear or that you use help instead of man. It is, after all, a game. This means you don’t have to feel bad using the buy command to purchase a program on the virtual dark web, either. Hey, if you can shoot bad guys in an FPS game, why can’t you do business with fake cyber-criminals. Why should Grand Theft Auto players have all the fun?

You know how in a video game you are a much better shot and can sustain a lot more damage than you probably can in real life? The same principle applies here. Using the scan-analyze command helpfully tells you how many open ports connected computers have and how much hacking skill it will require to break in. That’d be handy in real life, we bet.

We did think it was bad form that the tutorial admonished us for not entering the commands it wanted us to. What kind of hacker wouldn’t try something else? Anyway, it’s probably a better diversion than whatever Facebook or phone game your friends are wasting time with. It probably doesn’t impart any real hacking skills, but not everything has to be useful.

If you want a game that might teach you something, try the Bash crawl adventure. Or, go write and play some BASIC games in your browser.

3D Scanning Trouble? This Guide Has You Covered

June 26, 2022 by Donald Papp 9 Comments

When it comes to 3D scanning, a perfect surface looks a lot like the image above: thousands of distinct and random features, high contrast, no blurry areas, and no shiny spots. While most objects don’t look quite that good, it’s possible to get usable results anyway, and that’s what [Thomas] aims to help people do with his tips on how to create a perfect, accurate 3D scan with photogrammetry.

3D scanning in general is pretty far from being as simple as “point box, press button”, but there are tools available to make things easier. Good lighting is critical, polarizers can help, and products like chalk spray can temporarily add matte features to otherwise troublesome, shiny, or featureless objects. [Thomas] provides visuals of each of these, so one can get an idea of exactly what each of those elements brings to the table. There’s even a handy flowchart table to help troubleshoot and improve tricky scan situations.

[Thomas] knows his stuff when it comes to 3D scanning, seeing as he’s behind the OpenScan project. The last time we featured OpenScan was back in 2020, and things have clearly moved forward since then with a new design, the OpenScan Mini. Interesting in an open-sourced scanning solution? Be sure to give it a look.

Go-Kart Reverse Without The Pain

June 26, 2022 by Jenny List 20 Comments

Go-karts are a huge amount of fun, but often lack the most basic of mechanical conveniences such as a reverse gear. You can’t start a small four-stroke engine in reverse, so their simple chain drive transmissions lack the extra cogs to make it happen. Enter [HowToLou], who has given his go-kart a reversing option by the addition of an electric motor.

It’s an extremely simple arrangement, the motor is a geared 12 V item which drives a V-belt to the axle. The motor is mounted on a pivot with a lever, such that normally the belt isn’t engaged, thus reverse can be selected by pulling the lever. A simple button switch applies power to the motor, meaning that the machine can travel sedately backwards on electric power.

We’re not entirely convinced by the integrity of some of his fixings and it would be interesting to see how much the V-belt wears under the influence of the pulley when not engaged, but as an alternative to a full gearbox we can see the point. But then again as regular readers may know, we’re more used to full electric traction.

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Quantum Circuit Uses Just A Few Atoms

June 25, 2022 by Al Williams 5 Comments

Researchers at the University of New South Wales and a startup company, Silicon Quantum Computing, published results of their quantum dot experiments. The circuits use up to 10 carbon-based quantum dots on a silicon substrate. Metal gates control the flow of electrons. The paper appears in Nature and you can download the full paper from there.

What’s new about this is that the dots are precisely arranged to simulate an organic compound, polyacetylene. This allowed researchers to model the actual molecule. Simulating molecules is important in the study of exotic matter phases, such as superconductivity. The interaction of particles inside, for example, a crystalline structure is difficult to simulate using conventional methods. By building a model using quantum techniques on the same scale and with the same topology as the molecule in question, simulation is simplified.

The SSH (Su-Schreffer-Heeger) model describes a single electron moving along a one-dimensional lattice with staggered tunnel couplings. At least, that’s what the paper says and we have to believe it. Creating such a model for simple systems has been feasible, but for a “many body” problem, conventional computing just isn’t up to the task. Currently, the 10 dot model is right at the limit of what a conventional computer can simulate reasonably. The team plans to build a 20 dot circuit that would allow for unique simulations not feasible with classic computing tech.

The dots are made with a scanning tunneling microscope and there is a Goldilocks effect regarding the size of the dots. If they are too small, the energy levels are overwhelmed by phosphorous donors. Too large, and capacitive coupling between dots makes the system unstable.

We’ll admit, the science in the paper is pretty dense. But the Methods section outlines what it takes to create something like this. You’ll need silicon, high-temperature ovens, and the ability to handle exotic gasses and perform lithography. Pretty much an IC fab in your basement. However, we did wonder if anyone homebrewing chips had ever tried STM lithography like this as an alternative to optical lithography. Seems like it might be possible.

We can’t help with some of the more exotic gear, but if you want to build an STM, it has been done. While you can make quantum dots in your kitchen, we don’t think they are going to work the same.

The Prints Don’t Stop With This Prusa I3 MK3 Mod

June 25, 2022 by Matthew Carlson 21 Comments

One of the issues with 3D printing is that when a print is done, you need to go back and pull the print off the bed to reset it for the next one. What if you needed to print 600 little parts for whatever reason? Most people might say get lots of printers and queue them up. Not [Pierre Trappe], as he decided that his Prusa i3 MK3S+ would print continuously.

The setup was dubbed Loop and consisted of a few parts. First, there’s an arm that sweeps the build plate to clear the printed pieces, a slide for the pieces to descend on, and a stand for the printer to sit on that puts it at an angle. The next step is to modify OctoPrint to allow a continuous print queue. The slicer needs to change as [Pierre] provides some G-code to reset the printer and clear the print.

We were especially impressed with the attention to detail in the documentation for this one. There’s extensive guidance on getting the bed adhesion just right, as you can’t have it come off mid-print, but you need it to detach cleanly and easily when the arm sweeps across the bed. Calibrating that first layer is essential, and he provides handy instructions to dial it in. Additionally, temperature and material play a crucial role, and [Pierre] documented the different materials and temperatures he used while developing Loop.

While continuous belt printers are arguably the “correct” answer to the question of printing 600 little parts, they come with their own baggage. Being able to pull off something similar on a printer as reliable and well supported as the Prusa i3 makes for a compelling alternative.

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picture of a brambling (a small bird), with "BirdNET-Pi" written above it

Neural Network Identifies Bird Calls, Even On Your Pi

June 25, 2022 by Arya Voronova 20 Comments

Recently, we’ve stumbled upon the extensive effort that is the BirdNET research platform. BirdNET uses a neural network to identify birds by the sounds they make, and is a joint project between the Cornell Lab of Ornithology and the Chemnitz University of Technology. What strikes us is – this project is impressively featureful and accessible for a variety of applications. No doubt, BirdNET is aiming to become a one-stop shop for identifying birds as they sing.

There’s plenty of ways BirdNET can help you. Starting with likely the most popular option among us, there are iOS and Android apps – giving the microphone-enabled “smart” devices in our pockets a feature even the most app-averse hackers can respect. However, the BirdNET team also talks about bringing sound recognition to our browsers, Raspberry Pi and other SBCs, and even microcontrollers. We can’t wait for someone to bring BirdNET to a RP2040! The code’s open-source, the models are freely available – there’s hardly a use case one couldn’t cover with these.

About that Raspberry Pi version! There’s a sister project called BirdNET-Pi – it’s an easy-to-install software package intended for the Raspberry Pi OS. Having equipped your Pi with a USB sound card, you can make it do 24/7 recording and analysis using a “lite” version of BirdNET. Then, you get a web interface you can log into and see bird sounds identified in real-time. Not just that – BirdNET-Pi also processes the sounds and creates spectrograms, keeps the sound in a database, and can even send you notifications.

The BirdNET-Pi project is open, too, of course. Not just that – the BirdNET-Pi team emphasizes everything being fully local, unless you choose otherwise, and perhaps decide to share it with others. Many do make their BirdNET-Pi instances public, and there’s a lovely interactive map that shows bird sounds all across the world!

BirdNET is, undoubtedly, a high-effort project – and a shining example of what a dedicated research team can do with a neural network and an admirable goal in mind. For many of us who feel joy when we hear birds outside, it’s endearing to know that we can plug a USB sound card into our Pi and learn more about them – even if we can’t spot them or recognize them by sight just yet. We’ve covered bird sound recognition on microcontrollers before – also using machine learning.