A man is looking at a volumetric display while using one finger to interact with it. Two roughly-spherical blue shapes are visible in the display, and he is moving his index finger toward one of them.

Elastic Bands Enable Touchable Volumetric Display

April 14, 2025 by 12 Comments

Amazing as volumetric displays are, they have one major drawback: interacting with them is complicated. A 3D mouse is nice, but unless you’ve done a lot of CAD work, it’s a bit unintuitive. Researchers from the Public University of Navarra, however, have developed a touchable volumetric display, bringing touchscreen-like interactions to the third dimension (preprint paper).

At the core, this is a swept-volume volumetric display: a light-diffusing screen oscillates along one axis, while from below a projector displays cross-sections of the scene in synchrony with the position of the screen. These researchers replaced the normal screen with six strips of elastic material. The finger of someone touching the display deforms one or more of the strips, allowing the touch to be detected, while also not damaging the display.

The actual hardware is surprisingly hacker-friendly: for the screen material, the researchers settled on elastic bands intended for clothing, and two modified subwoofers drove the screen’s oscillation. Indeed, some aspects of the design actually cite this Hackaday article. While the citation misattributes the design, we’re glad to see a hacker inspiring professional research.) The most exotic component is a very high-speed projector (on the order of 3,000 fps), but the previously-cited project deals with this by hacking a DLP projector, as does another project (also cited in this paper as source 24) which we’ve covered.

While interacting with the display does introduce some optical distortions, we think the video below speaks for itself. If you’re interested in other volumetric displays, check out this project, which displays images with a levitating styrofoam bead.

Continue reading “Elastic Bands Enable Touchable Volumetric Display” →

A Low F Number Lens, From Scratch

April 6, 2025 by 52 Comments

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length. Lenses with low F-numbers are prized by photographers for their properties, but are usually expensive because making a good one can be something of a challenge. Nevertheless [Rulof] is giving it a go, making an 80mm F0.5 lens with a Sony E-mount. The video below the break has all the details, and also serves as a fascinating primer on lens design if you are interested.

Rather than taking individual lenses, he’s starting with the second-hand lens from an old projector. It’s got the required huge aperture, but it’s by no means a photographic lens. An interesting component is his choice of diaphragm for the variable aperture, it’s a drafting aid for drawing circles which closely resembles a photographic part. This is coupled with the triplet from an old SLR lens in a 3D-printed enclosure, and the result is a lens that works even if it may not be the best. We know from experiences playing with lens systems that adjusting the various components of a compound lens like this one can be very difficult; we can see it has the much sought-after bokeh or blurred background, but it lacks sharpness.

Perhaps because a camera is an expensive purchase, we don’t see as much of this kind of hacking as we’d like. That’s not to say that lenses don’t sometimes make their way here.

Continue reading “A Low F Number Lens, From Scratch” →

A TV With Contrast You Haven’t Seen For Years

March 5, 2025 by 42 Comments

It’s something of a surprise, should you own a CRT TV to go with your retrocomputers, when you use it to view a film or a TV show. The resolution may be old-fashioned, but the colors jump out at you, in a way you’d forgotten CRTs could do. You’re seeing black levels that LCD screens can’t match, and which you’ll only find comparable on a modern OLED TVs. Can an LCD screen achieve decent black levels? [DIY Perks] is here with a modified screen that does just that.

LCD screens work by placing a set of electronic polarizing filters in front of a bright light. Bright pixels let through the light, while black pixels, well, they do their best, but a bit of light gets through. As a result, they have washed-out blacks, and their images aren’t as crisp and high contrast as they should be. More modern LCDs use an array of LEDs as the backlight which they illuminate as a low resolution version of the image, an approach which improves matters but leaves a “halo” round bright spots.

The TV in the video below the break is an older LCD set, from which he removes the backlight and places the electronics in a stand. He can show an image on it by placing a lamp behind it, but he does something much cleverer. An old DLP projector with its color wheel removed projects a high-res luminance map onto the back of the screen, resulting in the coveted high contrast image. The final result uses a somewhat unwieldy mirror arrangement to shorten the distance for the projector, but we love this hack. It’s not the first backlight hack we’ve seen, but perhaps it give the best result.

Continue reading “A TV With Contrast You Haven’t Seen For Years” →

Hackaday Podcast Episode 298: Forbidden USB-C, A Laser Glow-o-Scope, And The Epoch Super Cassette Vision

November 29, 2024 by 5 Comments

This week’s Hackaday podcast has a European feel, as Elliot Williams is joined by Jenny List for a look at the week’s happenings in the world of cool hardware hacks. Starting with the week’s news, those Redbox vending machines continue to capture the attention of hackers everywhere, and in the race to snag one before they’re carted off for recycling someone has provided the missing hardware manual in the form of a wiki. Europeans can only look on wistfully. Then there’s the curious case of life on the asteroid sample, despite the best efforts of modern science those pesky earth bacteria managed to breach all their anti-contamination measures. Anyone who’s had a batch of homebrew go bad feels their pain.

The week provided plenty of hacks, with the team being wowed by [Bitluni]’s CRT-like laser projector, then the many ingenious ways to 3D-print a hinge, and perhaps one of the most unforgiving environments in the home for a piece of robotics. Meanwhile our appetite for cool stuff was sated by an entire family of Japanese games consoles we’d never heard of, and the little voltage reference whose data sheet also had an audio amplifier circuit. Finishing up, our colleague Arya has many unorthodox uses for a USB-C cable, and we have a frank exchange of views about Linux audio.

Give it a listen below and check out all the links, and by all means, give us a roasting in the comments!

Continue reading “Hackaday Podcast Episode 298: Forbidden USB-C, A Laser Glow-o-Scope, And The Epoch Super Cassette Vision” →

Custom built RGB laser firing beam

Lasers, Galvos, Action: A Quest For Laser Mastery

November 22, 2024 by 1 Comment

If you’re into hacking hardware and bending light to your will, [Shoaib Mustafa]’s latest project is bound to spike your curiosity. Combining lasers to project multi-colored beams onto a screen is ambitious enough, but doing it with a galvanomirror, STM32 microcontroller, and mostly scratch-built components? That’s next-level tinkering. This project isn’t just a feast for the eyes—it’s a adventure of control algorithms, hardware hacks, and the occasional ‘oops, that didn’t work.’ You can follow [Shoaib]’s build log and join the journey here.

The nitty-gritty is where it gets fascinating. Shoaib digs into STM32 Timers, explaining how modes like Timer, Counter, and PWM are leveraged for precise control. From adjusting laser intensity to syncing galvos for projection, every component is tuned for maximum flexibility. Need lasers aligned? Enter spectrometry and optical diffusers for precision wavelength management. Want real-time tweaks? A Python-controlled GUI handles the instruments while keeping the setup minimalist. This isn’t just a DIY build—it’s a work of art in problem-solving, with successes like a working simulation and implemented algorithms along the way.

If laser projection or STM32 wizardry excites you, this build will inspire. We featured a similar project by [Ben] back in September, and if you dig deep into our archives, you can eat your heart out on decades of laser projector projects. Explore Shoaib’s complete log on Hackaday.io. It is—literally—hacking at its most brilliant.

Geochron world time clock

Geochron: Another Time, Another Timeless Tale

October 26, 2024 by 10 Comments

The Geochron World Time Indicator is a clock that doubles as a live map of where the sun is shining on the Earth. Back in its day, it was a cult piece that some have dubbed the “Rolex on the wall.” Wired’s recent coverage of the clock reminded us of just how cool it is on the inside. And to dig in, we like [Attoparsec]’s restoration project on his own mid-1980s Geochron, lovingly fixing up a clock he picked up online.

[Attoparsec]’s recent restoration shares insights into the clock’s fascinating mechanics. Using a synchronous motor, transparent slides, and a lighted platen, the Geochron works like a glorified slide projector, displaying the analemma—a figure-eight pattern that tracks the sun’s position over the year.

But if you’re looking for a digital version, way back in 2011 we showcased [Justin]’s LED hack of FlorinC’s “Wise Clock”, which ingeniously emulated the Geochron’s day-night pattern using RGB LEDs, swapping out the faceplate for a world map printed on vellum. That’s probably a much more reasonable way to go these days. Why haven’t we seen more remakes of these?

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Key Cap Map

July 23, 2024 by 5 Comments

So, [zyumbik]’s trademark seems to be sexing things up, and the Artsey layout did not escape their gaze. This is the Sexy Artsey. Let’s back up a bit.

A pink and purple 10-key keyboard with a rotary encoder, spikes, and a custom area with LEGO attached.
Image by [zyumbik] via reddit
Artsey is a keyboard layout for chording, and this keyboard is built for it. It’s a one-handed keyboard meant for pressing multiple keys at a time to produce each character. With some use, [zyumbik] discovered that the Taipo layout might be a better fit, so there are currently some elements of both.

If you’d like to make this adorable keyboard, everything is waiting for you to download, including files for various thingamabobs you can stick on the side there where the rainbow is now. There’s also a groovy flower version of the knob.

Controller-wise, you can use a Seeed Studio Xiao in either BLE or RP2040 format, or the Waveshare RP2040 Zero. The firmware is written in ZMK.

Remember the death metal macropad? (Who could forget that tentacled nightmare?) This is the same creator. Kind of hard to believe, innit? Well, except for the spikes. Apparently they’re for thumb discipline.

Via reddit

Continue reading “Keebin’ With Kristina: The One With The Key Cap Map” →