Mesh “Lens” Lets Your Camera Make Weird Pixel Art

December 24, 2025 by No comments

We seldom talk about 3D printing lenses because most techniques can’t possibly produce transparent parts of optical quality. However, you can 3D print something like a lens, as [Luke Edwin] demonstrates, and get all kinds of crazy pictures out of it. 

[Luke’s] lens isn’t really a lens, per se. There’s no transparent optical medium being used to bend light, here. Instead, he’s printed a very fine grid in a cylindrical form factor, stuck it on a lens mount, and put that on the front of a camera.

The result is effectively a set of parallel tubes that guide light on to the camera’s image sensor. With the lack of any sort of focus mechanism, you can’t use this “lens” to photograph anything more than a few centimeters away. Get something up close, though, and you can take very simple, very grainy images that are reminiscent of classic pixel art. [Luke] demonstrates this in some fun ways, using it to take photographs of money, a plant, and his own eye. The images look almost like art assets straight out of a 16-bit game. He’s got the STL file up for sale if you want to print your own at home.

We’d love to see this concept explored further, maybe with some supporting optics for more versatile use. In the meantime, you might explore other ways of using 3D printers for photographic gain.

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Abusing X86 SIMD Instructions To Optimize PlayStation 3 Emulation

December 24, 2025 by No comments

Key to efficient hardware emulation is an efficient mapping to the underlying CPU’s opcodes. Here one is free to target opcodes that may or may not have been imagined for that particular use. For emulators like the RPCS3 PlayStation 3 emulator this has led to some interesting mappings, as detailed in a video by [Whatcookie].

It’s important to remember here that the Cell processor in the PlayStation 3 is a bit of an odd duck, using a single regular PowerPC core (PPE) along with multiple much more simple co-processors called synergistic processing elements (SPEs) all connected with a high-speed bus. A lot of the focus with Cell was on floating point vector – i.e. SIMD – processing, which is part of why for a while the PlayStation 3 was not going to have a dedicated GPU.

As a result, it makes perfect sense to do creative mapping between the Cell’s SIMD instructions and those of e.g. SSE and AVX, even if Intel removing AVX-512 for a while caused major headaches. Fortunately some of those reappeared in AVX2.

The video goes through a whole range of Cell-specific instructions, how they work, and what x86 SIMD instructions they were mapped to and why. The SUBD instruction for example is mapped to VPDPBUSD as well as VDBPSADBW in AVX-512, the latter of which mostly targets things like video encoding. In the end it’s the result that matters, even if it also shows why the Cell processor was so interesting for high-performance compute clusters back in the day.

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Disposable Camera Viewfinder Becomes 3D Printed Lens

December 24, 2025 by 3 Comments

Disposable cameras are a fun way to get into classical photography. However, they can also be a valuable source of interesting parts that can be put to other uses. For example, as [Billt] demonstrates, their viewfinders can be repurposed into a rather interesting lens for more serious cameras.

[Billt] was lucky enough to score a grabbag of used disposable cameras from a local film lab, and tore them down for parts. He was particularly interested in the viewfinders, since Kodak equipped its disposable cameras with actual plastic lenses for this very purpose.

[Billt] wanted to see what these lenses would do when thrown on the front of a proper digital camera, and set about designing a mount for that purpose. The 3D printed part was designed to mount one of the viewfinder lens assemblies on the front of any Sony E-mount camera. In a rather nifty trick, [Billt] realized the lens assembly could be installed in the adapter by pausing mid-way through the 3D print to drop it in. The only unfortunate thing? The lenses didn’t really work, and all the camera could see was a haze of unfocused light.

With the aid of some cardboard experiments, [Billt] decided to make some changes. The front element of the viewfinder was dumped, with the rear element being used solo instead. This was fitted to the adapter on a simple slide mechanism so that focus could be reliably adjusted. With these changes, the lens came good, and provided some really interesting shots. It’s quite a cropped lens and it can achieve a very close focus distance, as little as 1 inch in testing. It’s quite sharp in the center of the image, while softly blurring out towards the edges—something that sounds very familiar if you’ve used one of these disposable cameras in the wild.

Sometimes it’s fun to grab a random piece of junk to see if you can turn it into something good. Video after the break.

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DIY E-Reader Folds Open Like A Book

December 24, 2025 by 10 Comments

There are plenty of lovely e-readers out on the market that come with an nice big e-paper display. There aren’t nearly as many that come with two. [Martin den Hoed] developed the Diptyx e-reader with such a design in order to better replicate the paper books of old. 

The build is based around the ESP32-S3, a powerful microcontroller which comes with the benefit of having WiFi connectivity baked in. It’s hooked up to a pair of 648×480 e-paper displays, which are installed in a fold-open housing to create the impression that one is reading a traditional book. The displays themselves are driven with custom look-up tables to allow for low-latency updates when turning pages. The firmware of the device is inspired by the epub reader from [Atomic14], and can handle different fonts and line spacing without issue. Power is from a pair of 1,500 mAh lithium-polymer cells, which should keep the device running for a good long time, and they can be charged over USB-C like any  modern gadget.

You can follow along with the project on the official website, or check it out on Crowd Supply if you’re so inclined. The project is intended to be open source, with files to be released once the design is finalized for an initial production run.

We’ve seen some great DIY e-reader builds over the years, and we’re loving the development we’re seeing in the writer deck space, too. If you’re whipping up something fun in this vein, be sure to let us know on the tipsline!

Roll Your Own Hall Effect Sensor

December 24, 2025 by 6 Comments

If you read about Hall effect sensors — the usual way to detect and measure magnetic fields these days — it sounds deceptively simple. There’s a metal plate with current flowing across it in one direction, and sensors at right angles to the current flow. Can it really be that simple? According to a recent article in Elektor, [Burkhard Kainka] says yes.

The circuit uses a dual op amp with very high gain, which is necessary because the Hall voltage with 1 A through a 35 micron copper layer (the thickness on 1 oz copper boards) is on the order of 1.5 microvolts per Tesla. Of course, when dealing with tiny voltages like that, noise can be a problem, and you’ll need to zero the amplifier circuit before each use.

The metal surface? A piece of blank PCB. Copper isn’t the best material for a Hall sensor, but it is readily available, and it does work. Of course, moving the magnet can cause changes, and the whole thing is temperature sensitive. You wouldn’t want to use this setup for a precision measurement. But for an experimental look at the Hall effect, it is a great project.

Today, these sensors usually come in a package. If you want to know more about the Hall effect, including who Edwin Hall was, we can help with that, too.

Silicon-Based MEMS Resonators Offer Accuracy In Little Space

December 24, 2025 by 1 Comment

Currently quartz crystal-based oscillators are among the most common type of clock source in electronics, providing a reasonably accurate source in a cheap and small package. Unfortunately for high accuracy applications, atomic clocks aren’t quite compact enough to fit into the typical quartz-based temperature-compensated crystal oscillators (TCXOs) and even quartz-based solutions are rather large. The focus therefore has been on developing doped silicon MEMS solutions that can provide a similar low-drift solution as the best compensated quartz crystal oscillators, with the IEEE Spectrum magazine recently covering one such solution.

Part of the DARPA H6 program, [Everestus Ezike] et al. developed a solution that was stable to ±25 parts per billion (ppb) over the course of eight hours. This can be contrasted with a commercially available TCXO like the Microchip MX-503, which boasts a frequency stability of ±30 ppb.

Higher accuracy is achievable by swapping the TCXO for an oven-controlled crystal oscillator (OCXO), with the internal temperature of the oscillator not compensated for, but rather controlled with an active heater. There are many existing OCXOs that offer down to sub-1 ppb stability, albeit in quite a big package, such as the OX-171 with a sizable 28×38 mm footprint.

With a MEMS silicon-based oscillator in OXCO configuration [Yutao Xu] et al. were able to achieve a frequency stability of ±14 ppb, which puts it pretty close to the better quartz-based oscillators, yet within a fraction of the space. As these devices mature, we may see them eventually compete with even the traditional OCXO offerings, though the hyperbolic premise of the IEEE Spectrum article of them competing with atomic clocks should be taken with at least a few kilograms of salt.

Thanks to [anfractuosity] for the tip.

Nixie Tube Dashboard Is Period-Appropriate Hack To Vintage Volvo

December 24, 2025 by 9 Comments

There’s no accounting for taste, but it’s hard to argue with The Autopian when they declare that this Nixie tube dash by [David Forbes] is “the coolest speedometer of all time” — well, except to quibble that it’s also the coolest tachometer, temperature gauge, oil pressure indicator, and voltmeter. Yeah, the whole instrument cluster is on [David]’s Volvo PV544 is nixified, and we’re here for it.

He’s using a mixture of tubes here– the big ones in the middle are the speedo and tachometer, while the ovals on either side handle the rest. There’s a microcontroller on the front of the firewall that acts a bit like a modern engine control unit (ECU) — at least for the gauges; it sounds like the Volvo’s engine is stock, and that means carbureted for a car of that vintage.

The idea that this hack could have been done back in the 50s when the car was new just tickles us pink. Though you’d have probably needed enough valves to fill up the boot, as our British friends would say. Translate that to “enough vacuum tubes to fill the trunk” if you’re in one of the rebellious colonies.

We’ve featured [David]’s projects previously, in the form of his wearable video coat. But his best known work is arguably the Nixie Watch, famously the timepiece of choice for Steve Wozniak.

Thanks to [JohnU] for the tip!

All images by Griffin Riley via The Autopian