DIY Night Vision, Where Four Is Better Than Two

Night vision projects are great, and the hardware available to hobbyists just gets better and better. [Just Call Me Koko] shows off just such a build using four low-light, IR-sensitive cameras, four displays, and four lenses in 3D printed enclosures mounted to a helmet. Why four? Well, mounting two cameras and displays per eye is the easiest way to yield a wider field of view, and for bonus points, it sure looks extra weird.

At its heart, each of the four segments is the same. A Foxeer Night Cat 3 camera is mounted at the front, its output is connected directly to a 2″ diagonal NTSC/PAL display, and at the rear is a DCX (double convex) lens 38 mm in diameter with a 50 mm focal length. Add a printed enclosure, and the result is a monocular night vision display. Do it three more times and arrange them around one’s eyeballs, and one can make a night vision system with a panoramic view that probably takes only a little getting used to.

How well does it work? [Just Call Me Koko] does some walking around and also tries some target practice while wearing them, and concludes that while they don’t have nearly the clarity of the real deal (the 320×240 resolution displays limit the details one can perceive), they do work fairly well for what they are. Also, the cost of parts is a small fraction of the cost of the real thing, making it a pretty enjoyable project in the end.

The kind of hardware available to hobbyists today is what makes this kind of night vision project accessible, but there’s always the good old high-voltage analog method.

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VR Prototypes Reveal Facebook’s Surprisingly Critical Research Directions

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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3D Scanning Trouble? This Guide Has You Covered

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.

Scrambling Pocket Calculators Made Easy With EMP Box V2

[Rostislav Persion] has for some time been interested in making small, portable EMP devices capable of interfering with nearby electronics. In these EMP devices, high voltage is used to create a portable spark gap generator, whose operation in turn creates electromagnetic pulses capable of resetting or scrambling nearby electronics such as pocket calculators.

Bridging adjacent holes narrows the spark gap, resulting in more frequent pulses.

His original EMP box designs relied on spark gaps constructed from metal screws threaded into a clear plastic insulator, but this newest design ditches fussy screw adjustments and relies on perfboard. By cutting out a single row of plated perfboard holes and soldering the high voltage terminals to each end, the empty holes in between form the essential parts of a spark gap.

It’s even adjustable: one simply bridges adjacent holes with solder to effectively decrease the gap. As for generating the high voltage itself, a DC voltage multiplier from Amazon takes care of that. Watch the device reset some calculators in the short video below.

Looking for high-voltage experiments that aren’t so sketchy? Get yourself a Van de Graff generator, some metal balls, and a little bit of oil, and make some art.

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Tips For Winding Durable Coils With Nice, Flat Sides

[Drew Pilcher] needed durable, custom-wound coils with no core, and perfectly flat sides. Coils can be wound by hand, of course, but reliably creating perfect coils with thin wire and lots of layers requires some additional help. Happily, [Drew] shares his method for doing exactly that. Perhaps coming as no surprise, the key to repeatable, high-quality coils is good preparation and tools.

The most important part is the ability to rotate a spool for winding without having to take one’s hands off the workpiece. To accomplish this, a cheap, no-name power drill and foot pedal (made from the harvested trigger unit of the drill) forms the basis of [Drew]’s DIY winder. To make coils with precision, one must also count the number of turns. Thankfully, there is a simple solution for this; [Drew] used a cheap digital turn counter from Amazon. This economical device uses a magnet and sensor, so [Drew] simply stuck the magnet on the side of the drill’s chuck.

Careful winding and a liberal application of CA glue helps ensure good results.

The spool is what the wire gets wound around to form the coil, and it will need to be removed from the coil afterwards. To accomplish this, [Drew] uses a brass shaft, metal washers, and some plastic spacers. A light coating of grease on the spool surfaces helps ensure things come apart properly in the end.

To actually make the coil, [Drew] recommends some means of magnification, and a supply of CA glue. Wind the wire as cleanly and closely as possible, and apply CA glue during the process to secure things. It takes some practice, but really clean windings are possible if done correctly.

For thick coils with a lot of layers, the CA glue will hold things together well enough, but for smaller coils [Drew] likes to give them a final coating of two-part epoxy. After things are completely set, the spool is disassembled and the inner core is pushed out as gently as possible.

The result? A tightly-wound, durable coil with perfectly flat sides. It’s exactly the thing [Drew] needs for his upcoming coil gun project. How’s that work, you wonder? You can see the basics covered right here.

Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

3D Printering: Today’s Resins Can Meet Your Needs

Filament-based 3D printers spent a long time at the developmental forefront for hobbyists, but resin-based printers have absolutely done a lot of catching up, and so have the resins they use. It used to be broadly true that resin prints looked great but were brittle, but that’s really not the case anymore.

A bigger variety of resins and properties are available to hobbyists than ever before, so if that’s what’s been keeping you away, it’s maybe time for another look. There are tough resins, there are stiff resins, there are heat-resistant resins, and more. Some make casting easy, and some are even flexible. If your part or application needs a particular property, there is probably a resin for it out there.

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Homebrew An OS From Scratch? Snowdrop Shows How It’s Done

Ever wondered what it would take to roll your own OS? [Sebastian]’s Snowdrop OS might just provide you with some insight into that process, and maybe even some inspiration.

[Sebastian] created Snowdrop completely from scratch, using only x86 assembly language. It’s more than just bare-bones, and boasts a number of useful utilities and programs including a BASIC interpreter and linker (for creating standalone BASIC executables.) That’s not even touching on the useful essentials, like multitasking and a GUI framework. There are even a number of resources specifically for making game development easier. Because as [Sebastian] puts it, what’s a operating system without games?

Interested in giving Snowdrop a try, or peek at the source code? The binaries and sources section has all you need, and the other headings at the top of the page will send you to the various related goodies. If you have a few minutes, we recommend you watch a walkthrough of the various elements and features of Snowdrop in this video tour (embedded after the page break.)

Snowdrop is an ambitious project, but we’re not surprised that [Sebastian] has made it work; we’ve seen his low-level software skills before, with his fantastic efforts around the classic stand-up arcade game, Knights of the Round.

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