Contagious Ideas

March 29, 2025 by Elliot Williams 10 Comments

We ran a story about a wall-mounted plotter bot this week, Mural. It’s a simple, but very well implemented, take on a theme that we’ve seen over and over again in various forms. Two lines, or in this case timing belts, hang the bot on a wall, and two motors drive it around. Maybe a servo pulls the pen in and out, but that’s about it. The rest is motor driving and code.

We were thinking about the first such bot we’ve ever seen, and couldn’t come up with anything earlier than Hektor, a spray-painting version of this idea by [Juerg Lehni]. And since then, it’s reappeared in numerous variations.

Some implementations mount the motors on the wall, some on the bot. There are various geometries and refinements to try to make the system behave more like a simple Cartesian one, but in the end, you always have to deal with a little bit of geometry, or just relish the not-quite-straight lines. (We have yet to see an implementation that maps out the nonlinearities using a webcam, for instance, but that would be cool.) If you’re feeling particularly reductionist, you can even do away with the pen-lifter entirely and simply draw everything as a connected line, Etch-a-Sketch style. Maslow CNC swaps out the pen for a router, and cuts wood.

What I love about this family of wall-plotter bots is that none of them are identical, but they all clearly share the same fundamental idea. You certainly wouldn’t call any one of them a “copy” of another, but they’re all related, like riffing off of the same piece of music, or painting the same haystack in different lighting conditions: robot jazz, or a study in various mechanical implementations of the same core concept. The collection of all wall bots is more than the sum of its parts, and you can learn something from each one. Have you made yours yet?

(Fantastic plotter-bot art by [Sarah Petkus] from her write-up ten years ago!)

Generative Art Machine Does It One Euro At A Time

March 22, 2025 by Elliot Williams 14 Comments

[Niklas Roy] obviously had a great time building this generative art cabinet that puts you in the role of the curator – ever-changing images show on the screen, but it’s only when you put your money in that it prints yours out, stamps it for authenticity, and cuts it off the paper roll with a mechanical box cutter.

If you like fun machines, you should absolutely go check out the video, embedded below. The LCD screen has been stripped of its backlight, allowing you to verify that the plot exactly matches the screen by staring through it. The screen flashes red for a sec, and your art is then dispensed. It’s lovely mechatronic theater. We also dig the “progress bar” that is represented by how much of your one Euro’s worth of art it has plotted so far. And it seems to track perfectly; Bill Gates could learn something from watching this. Be sure to check out the build log to see how it all came together.

You’d be forgiven if you expected some AI to be behind the scenes these days, but the algorithm is custom designed by [Niklas] himself, ironically adding to the sense of humanity behind it all. It takes the Unix epoch timestamp as the seed to generate a whole bunch of points, then it connects them together. Each piece is unique, but of course it’s also reproducible, given the timestamp. We’re not sure where this all lies in the current debates about authenticity and ownership of art, but that’s for the comment section.

If you want to see more of [Niklas]’s work, well this isn’t the first time his contraptions have graced our pages. But just last weekend at Hackaday Europe was the first time that he’s ever given us a talk, and it’s entertaining and beautiful. Go check that out next. Continue reading “Generative Art Machine Does It One Euro At A Time” →

The Strange Afterlife Of The Xbox Kinect

March 6, 2025 by Dave Rowntree 32 Comments

The tale of the Microsoft Xbox Kinect is one of those sad situations where a great product was used in an application that turned out to be a bit of a flop and was discontinued because of it, despite its usefulness in other areas. This article from the Guardian is a quick read on how this handy depth camera has found other uses in somewhat niche areas, with not a computer game in sight.

It’s rather obvious that a camera that can generate a 3D depth map, in parallel with a 2D reference image, could have many applications beyond gaming, especially in the hands of us hackers. Potential uses include autonomous roving robots, 3D scanning, and complex user interfaces—there are endless possibilities. Artists producing interactive art exhibits would sit firmly in that last category, with the Kinect used in countless installations worldwide.

Apparently, the Kinect also has quite the following in ghost-hunting circles, which as many a dubious TV show would demonstrate, seem almost entirely filmed under IR light conditions. The Kinect’s IR-based structured light system is well-suited for these environments. Since its processing core runs a machine learning application specifically trained to track human figures, it’s no surprise that the device can pick up those invisible, pesky spirits hiding in the noise. Anyway, all of these applications depend on the used-market supply of Kinect devices, over a decade old, that can be found online and in car boot sales, which means one day, the Kinect really will die off, only to be replaced with specialist devices that cost orders of magnitude more to acquire.

In the unlikely event you’ve not encountered non-gaming applications for the Kinect, here’s an old project to scan an entire room to get you started. Just to be perverse, here’s a gaming application that Microsoft didn’t think of, and to round out, the bad news that Microsoft has really has abandoned the product.

Digital Paint Mixing Has Been Greatly Improved With 1930s Math

January 30, 2025 by Lewin Day 41 Comments

You might not have noticed if you’re not a digital artist, but most painting and image apps still get color mixing wrong. As we all learned in kindergarten, blue paint and yellow paint makes green paint. Try doing that in Photoshop, and you’ll get something altogether different—a vague, uninspiring brownish-grey. It’s the same story in just about every graphics package out there.

As it turns out, there’s a good reason the big art apps haven’t tackled this—because it’s really hard! However, a team of researchers at Czech Technical University has finally cracked this long-standing problem. The result of their hard work is Mixbox, a digital model for pigment-based color mixing. Once again, creative application of mathematics has netted aesthetically beautiful results!

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Cool Kinetic Sculpture Has Tooling Secrets To Share

January 29, 2025 by Dan Maloney 8 Comments

Occasionally, we get a tip for a project that is so compelling that we just have to write it up despite lacking details on how and why it was built. Alternatively, there are other projects where the finished product is cool, but the tooling or methods used to get there are the real treat. “Homeokinesis,” a kinetic art installation by [Ricardo Weissenberg], ticks off both those boxes in a big way.

First, the project itself. Judging by the brief video clip in the reddit post below, Homeokinesis is a wall-mounted array of electromagnetically actuated cards. The cards are hinged so that solenoids behind them flip the card out a bit, making interesting patterns of shadow and light, along with a subtle and pleasing clicking sound. The mechanism appears to be largely custom-made, with ample use of 3D printed parts to make the frame and the armatures for each unit of the panel.

Now for the fun part. Rather than relying on commercial solenoids, [Ricardo] decided to roll his own, and built a really cool CNC machine to do it. The machine has a spindle that can hold at least eleven coil forms, which appear to be 3D printed. Blank coil forms have a pair of DuPont-style terminal pins pressed into them before mounting on the spindle, a job facilitated by another custom tool that we’d love more details on. Once the spindle is loaded up with forms, magnet wire feeds through a small mandrel mounted on a motorized carriage and wraps around one terminal pin by a combination of carriage and spindle movements. The spindle then neatly wraps the wire on the form before making the connection to the other terminal and moving on to the next form.

The coil winder is brilliant to watch in action — however briefly — in the video below. We’ve reached out to [Ricardo] for more information, which we’ll be sure to pass along. For now, there are a lot of great ideas here, both on the fabrication side and with the art piece itself, and we tip our hats to [Ricardo] for sharing this.

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How The Lost Mystery Pigment ‘Maya Blue’ Got Recreated

December 14, 2024 by Donald Papp 16 Comments

A distinct blue pigment reminiscent of turquoise or a clear sky was used by the ancient Maya to paint pottery, sculptures, clothing, murals, jewelry, and even human sacrifices. What makes it so interesting is not only its rich palette — ranging from bright turquoise to a dark greenish blue — but also its remarkable durability. Only a small number of blue pigments were created by ancient civilizations, and even among those Maya blue is unique. The secret of its creation was thought to be lost, until ceramicist and artist [Luis May Ku] rediscovered it.

Maya blue is not just a dye, nor a ground-up mineral like lapis lazuli. It is an unusual and highly durable organic-inorganic hybrid; the result of a complex chemical process that involves two colorants. Here is how it is made: Indigotin is a dye extracted from ch’oj, the Mayan name for a specific indigenous indigo plant. That extract is combined with a very specific type of clay. Heating the mixture in an oven both stabilizes it produces a second colorant: dehydroindigo. Together, this creates Maya blue.

The road to rediscovery was not a simple one. While the chemical makeup and particulars of Maya blue had been known for decades, the nuts and bolts of actually making it, not to mention sourcing the correct materials, and determining the correct techniques, was a long road. [May] made progress by piecing together invaluable ancestral knowledge and finally cracked the code after a lot of time and effort and experimentation. He remembers the moment of watching a batch shift in color from a soft blue to a vibrant turquoise, and knew he had finally done it.

Before synthetic blue pigments arrived on the scene after the industrial revolution, blue was rare and highly valuable in Europe. The Spanish exploitation of the New World included controlling Maya blue until synthetic blue colorants arrived on the scene, after which Maya blue faded from common knowledge. [May]’s rediscovered formula marks the first time the world has seen genuine Maya blue made using its original formula and methods in almost two hundred years.

Maya blue is a technological wonder of the ancient world, and its rediscovery demonstrates the resilience and scientific value of ancestral knowledge as well as the ingenuity of those dedicated to reviving lost arts.

We’re reminded that paints and coatings have long been fertile ground for experimentation, and as an example we’ve seen the success people had in re-creating an ultra-white paint that actually has a passive cooling effect.

A brown sphere with a flat top, a nose and circular eyes sits on the ground surrounded by low vegetation. A wooden fence is behind it.

Making A Stool From Clay

November 30, 2024 by Navarre Bartz 8 Comments

We’ve seen furniture made out of all sorts of interesting materials here, but clay certainly isn’t the first one that comes to mind. [Mia Mueller] is expanding our horizons with this clay stool she made for her garden.

Starting with an out-of-budget inspiration piece, [Mueller] put her own spin on a ceramic stool that looks like a whimsical human head. An experienced potter, she shows us several neat techniques for working with larger pieces throughout the video. Her clay extruder certainly beats making coils by hand like we did in art class growing up! Leaving the coils wrapped in a tarp allows her to batch the process coils and leave them for several days without worrying about them drying out.

Dealing with the space constraints of her small kiln, her design is a departure from the small scale prototype, but seeing how she works through the problems is what really draws us to projects like this in the first place. If it was easy, it wouldn’t be making, would it? The final result is a beautiful addition to her garden and should last a long time since it won’t rot or rust.

If you’re thinking of clay as a medium, we have some other projects you might enjoy like this computer mouse, 3D printing with clay, or a clay battery.

Continue reading “Making A Stool From Clay” →