TechyMagThings

Although modern cameras can, with skill and good conditions, produce photographs nearly indistinguishable from the original scene, this fidelity relies on the limitations of human vision. According to the trichromatic theory, humans perceive light as a mixture of three colors, which can be recorded and represented by cameras, displays, and color printing; a spectrometer, however, can detect a clear distance between the three colors present in a photograph and the wide range of spectra in the original scene. By contrast, one of the earliest color photography methods, Lippmann plates, captured not just true color, but true spectra.

A Lippmann plate, as [Jon Hilty] details, starts with a layer of photographic gel containing extremely fine silver halide crystals over the back of a glass plate. This layer is placed on top of a mirror, traditionally a mercury bath, and put in the camera. When light passes through the emulsion and reflects off the mirror, it interferes with incoming light to create a standing wave. The portions of the emulsion at the wave’s antinodes absorb the most energy, converting local silver halide crystals into reflective silver. The spacing of the silver particles depends on the incoming light’s wavelength, and is fixed in place during the development process.

This creates a matrix of vertically-stacked diffraction gratings, each diffracting back the original wavelength when illuminated with white light. Unlike normal diffraction gratings, the wavelength of diffracted light doesn’t depend strongly on the viewing angle; since the interference structure here is vertically-arranged, it refracts a narrow range of wavelengths across all possible viewing angles. The viewing angles, however, are limited; unlike with dye-based photographs, you can only view the colors nearly straight-on. This, along with the necessity for long exposures, the chance of producing washed-out colors, and the impossibility of creating reprints, kept Lippmann plates from ever really catching on. The basic concept lives on in holograms, which encode spatial information in a similar kind of photographically-formed diffraction pattern.

For a more conventional method of color photography, we’ve also seen a recreation of the autochrome method. Alternatively, check out this homemade silver halide photography emulsion.

Thanks to [Stephen Walters] for the tip!

Although the ReactOS project is in no rush to dethrone Windows as the desktop operating system of choice, this doesn’t mean that some real changes aren’t happening. Most recently two big changes got merged, the first pertaining to the separate boot- and live CD images that are now merged into a single image, and the second being a new PnP-aware ATA storage stack for ATA and AHCI devices, with NT6+ compatibility.

Although there is still a separate live CD for now, this first change means that testing and installing ReactOS becomes easier, and that the old-school text-based installer may soon be on its way out as well.

Having the new ATA storage stack in place will translate into much better compatibility with real hardware, including the ability to use more hardware to install on and boot from compared to the old UniATA driver.

Combined, these two changes should bring the ReactOS installation and usage experience a lot closer to that of Windows, as well as many Linux distros. If you had issues with the OS on real hardware, this might be just the right time to give it another shake and provide detailed feedback to the developers if any remaining issues are encountered.

Thanks to [jeditobe] for the tip.

Software that collects public data from the Internet and uses it to provide half-assed answers to your questions might seem like a modern craze, but today we bid farewell to a website that helped pioneer pretend conversations all the way back in 1997 — as of May 1st, Ask Jeeves is no more.

Well, technically they dropped the “Jeeves” part back in 2006. Since then it’s just been Ask.com, but as the name implies the idea was more or less the same. Rather than the relatively rigid parameters and keywords required by traditional search engines, you could ask Jeeves questions about the world using natural language. Early advertisements showed the virtual valet answering arbitrary questions like “How many calories in a banana?,” which of course today seems commonplace and utterly unimpressive, but was a pretty wild for the 1990s.

It might seem surprising that a site designed from day one to offer a human-like Q&A experience should fold right as such technology is becoming commonplace. But of course, that commonality is the problem. When Google can answer your questions just as well (or poorly…) as Jeeves or anyone else, what’s the benefit for the average Internet user to seek out another service? But it’s still somewhat ironic, which is probably why the farewell message on Ask.com ends with the line “Jeeves’ spirit endures.”

While on the subject of technology that’s potentially ahead of its time, MacRumors is reporting that Apple is giving up on their Vision Pro augmented reality googles. They haven’t been formally discontinued as of yet, but sources indicate that the internal development team for the entire product line has been disbanded and reassigned to other projects within the company. This comes after a October 2025 refresh of the hardware still failed to connect with consumers. Insiders have said that not only were sales sluggish on the ~$3,500 headsets, but that they were getting returned at a far higher rate than any of Apple’s other hardware products.

Now, we’re hardly Apple apologists here at Hackaday. It sort of goes without saying that the whole “Walled Garden” thing doesn’t really fit our ethos. But we can’t deny that the Vision Pro is an impressive piece of technology. After years of sticking our phones in crappy plastic headsets, or trying to force hardware designed for VR gaming to do literally anything else, the Vision Pro offered a practical way to put augmented reality to work. But even for a company known for producing expensive hardware, the price tag was just too much for most consumers.

We’ll go out on a limb here and predict that the Vision Pro will one day be looked back on like the Newton — a product that was too expensive and niche to be a commercial success when it came out, but still a technical milestone that gave us a glimpse into the shape of things to come.

Speaking of a technology that will inevitably become more common, the European Patent Office (EPO) released a report this week showing a seven-fold increase in the number of inventions intended for battery reuse and recycling over the last decade. Given our insatiable demand for rechargeable batteries, it should come as no surprise that there’s a huge push for new methods of squeezing more use out of cells. As noted several times by the EPO, it’s not purely about saving money either. Even if Europe produces the batteries domestically, they need to import the raw materials. Relying on foreign countries to provide critical infrastructure can be precarious in the best of times, and is likely to only become more politically onerous in the future.

Finally, we’ll leave you with a fun way to waste some time on a Sunday evening: Visible Zorker. Created by Andrew Plotkin, this website allows you to not only play through all three installments of Zork, but presents a debugger-style view of the source code as the game is running. Even if you’re not terribly interested in seeing how your responses are parsed, the map that shows your progress through the world is certainly handy. The project was actually started back in 2025, but Andrew just completed the trilogy by adding support for Zork III a couple days ago so now is the perfect time to check it out.

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.

Triple monitor workstations are pretty common these days, particularly for those wishing to maximise screen space for greater productivity. [Will It Work?] has put together a sillier take on this concept, however, hooking the diminutive iPod Nano up to three monitors instead.

The 6th-generation iPod nano brought forth a new form factor – it’s the postage stamp-sized one that you could clip to your workout gear. It’s not typically what you’d call a productivity device, but there is a way to get more out of it. The trick is to grab a 30-pin Keyboard Dock, which allows access to the composite video signal from the iPod. It was originally designed for the iPad, but it works with the iPad nano too with a 30-pin spacer adapter – just don’t expect the keys to do anything. This setup also allows access to the 3.5mm four-pole jack, which handles audio input and output. With a bunch of additional cables and adapters, the iPod was able to be hooked up to three screens, a set of Apple Pro speakers, and three Sharp LCD monitors.

What can you do with this setup? Fundamentally, not a whole lot. You can’t use the keyboard with the iPod Nano, so you’re limited to interacting with the tiny touchscreen. There also aren’t exactly a lot of apps to run on the platform, either. You can basically listen to music, watch a slide show, or record voice memos, while looking at the iPod’s display spread identically across three TVs. Still, it’s a fun joke build, because at a glance it genuinely looks like you’ve set up a triple-monitor workstation running off a tiny iPod from over a decade ago.

If you want to blow the mind of your next podcast guest, consider recording your next episode on this rig. Alternatively, explore some of the other hacks we’ve seen for the platform. Video after the break.

C-3PO is one of the more famous movie robots out there. However, we don’t see a lot of replicas built, perhaps because in speech and mannerisms, he’s quite hard to replicate. Of course, that feat has become much more achievable with modern AI tech, as [Samuel Potozkin] demonstrates.

We’re not looking at a full C-3PO build here, it’s just the head—but for the project’s purposes, that’s all that was really required. The build relies on a Raspberry Pi 5 as the brains of the droid. It’s running a mic hooked up to a real time speech to text engine, and that text is then sent to a large language model for interpretation. Responses are then generated, passed through a processing layer to capture C-3PO’s general tone and vibe, and then handed off to a text-to-speech synth to imitate the iconic voice, played via speaker. The end result is a C-3PO you can actually talk to, which is something that might have knocked a few socks off when the movie first launched in 1977. In-depth materials for the build can be had via Google Drive and on Github.

This ersatz C-3PO isn’t an exact dupe of the movie ‘bot.  The protocol droid is a little slow to respond, and the patter isn’t quite on point, even if the voice synth makes a good effort at mimicking the original. Overall, it’s a little… robotic… something you wouldn’t say of the character in the movies. Still, it’s a great effort, and something we haven’t really seen much of before. If you like more classic droid replicas, though, we’ve featured those too. Video after the break.

Transistors in some circuit configurations work together and, frequently, need to be matched. This is so common that you can sometimes find ICs that are just a pair of transistors made with the same piece of silicon, so they should be matched very closely by default. But with discrete transistors, two devices of the same type are not always identical. [Learn Electronics Repair] covers the topic and explains how to match devices in the video below.

Depending on the circuit, the matching parameters may be different, but generally, the idea is that you want similar gains or matching saturation characteristics. The reason is that when you have multiple transistors working together, you don’t want one to do more work than the other device. This is inefficient and could drive the “better” component to fail.

The same idea applies in bridge circuits, where you might match resistors or capacitors to make sure that, for example, two 10% resistors are very close to the same value. A 10K resistor could be between 9K and 11K, and you might not care as long as they are both, say, 9.2K or both 10.8K.

This is different, by the way, from impedance matching, where you achieve maximum power transfer by matching a source to a load.

Once upon a time, someone set up a livestream wherein the messages from Twitch chat could control a game of Pokemon. Since then, we’ve seen Twitch control all sorts of things. If you’d like to have them play with some LEDs in your house, you might like this project from [pfeiffer3000].

The concept is simple enough. The heart of the build is an ESP32 microcontroller, which is easy to integrate with web services thanks to its onboard WiFi capability. It’s hooked upt o a string of WS2812B addressable RGB LEDs. The LEDs themselves are installed within table tennis balls to act as nice, spherical diffusers, and installed in a square frame made of PVC pipes. As for code, the rig uses the WLED library to drive the LED strings, and code from TwitchIO to interface with Twitch chat itself. It’s as simple as rigging up a bit of Python. With everything assembled, [pfeiffer3000] had an attractive LED grid that could be controlled directly by anyone watching their Twitch stream.

We’ve explored how to control things via Twitch before, too. It’s a fun way to add some interactivity to your livestream that really gets viewers involved. If you’ve been building your own audience-controlled projects, we’d love to hear about them on the tipsline!