IKEA LACK Table Becomes Extremely Affordable DIY Copy Stand

June 16, 2023 by Donald Papp 14 Comments

A copy stand is a tool used to capture images of photos, artwork, books, and things of a similar nature. It holds a camera perpendicular to a large and flat surface, upon which the subject rests.

A threaded rod provides effective vertical adjustment.

They are handy, but there’s no need to spend a lot when [BlandPasta]’s DIY copy stand based on a cheap IKEA LACK table can be turned into an economical afternoon project with the help of simple hardware and a few 3D printed parts.

The main structure comes from a mixture of parts from two LACK tables: one small and one normal-sized. A tabletop is used as the bed, and the square legs make up the structural parts with the help of some printed pieces. A threaded rod combined with some captive hardware provides a way to adjust the camera up and down with a crank, while one can manually slide the horizontal camera mount as needed to frame the subject appropriately.

This is a clever remix of IKEA parts, and the somewhat matte white finish of the LACK complements photography well. Adding some DIY LED lighting is about all it takes to get a perfectly serviceable copy stand that won’t break the bank.

These Illusions Celebrate Exploiting Human Senses

June 16, 2023 by Donald Papp 7 Comments

Illusions are perceptual experiences that do not match physical reality, and the 2023 Illusion of the Year contest produced a variety of nifty ones that are worth checking out. A video for each is embedded below the break, but we’ll briefly explain each as well.

Some of the visual illusions play with perspective. One such example happens to be the contest winner: Platform 9 3/4 has a LEGO car appear to drive directly through a wall. It happens so quickly it’s difficult to say what happened at all!

Another good one is the Tower of Cubes, which appears as two stacks of normal-looking hollow cubes, but some of the cubes are in fact truly bizarre shapes when seen from the side. This is a bit reminiscent of the ambiguous cylinder illusion by Japanese mathematician and artist [Kokichi Sugihara].

Cornelia is representative of the hollow face illusion, in which a concave face is perceived as a normal convex one. (Interestingly this illusion is used to help diagnose schizophrenia, as sufferers overwhelmingly fail to perceive the illusion.)

The Accelerando Illusion is similar to (but differs from) an auditory effect known as the Risset Rhythm by composer Jean-Claude Risset. It exploits ambiguities in sound to create a dense musical arrangement that sounds as though it is constantly increasing in tempo.

The Buddha’s Ear Illusion creates the illusion of feeling as though one’s earlobe is being stretched out to an absurd length, and brings to mind the broader concept of body transfer illusion.

While it didn’t appear into the contest, we just can’t resist bringing up the Thermal Grill Illusion, in which one perceives a painful burning sensation from touching a set of alternating hot and cold elements. Even though the temperatures of the individual elements are actually quite mild, the temperature differential plays strange tricks on perception.

A video of each of the contest’s entries is embedded below, and they all explain exactly what’s going on for each one, so take a few minutes and give them a watch. Do you have a favorite illusion of your own? Share it in the comments!

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Ferrofluid Drum Synth Dances To The Beat

June 15, 2023 by Donald Papp 17 Comments

[Love Hultén]’s work often incorporates reactive sound elements, and his Ferrofluid drum synth is no exception. Sadly there are no real build details but have no fear: we’ve gathered plenty of DIY insights when it comes to ferrofluid-based projects.

Ferrofluid isn’t easy to work with, but there are plenty of DIY resources to make things easier.

First of all, ferrofluid is shockingly expensive stuff. But if you can get your hands on some old VHS tapes and acetone, you can make your own. Second, working with ferrofluid to make reactive elements is harder than it may look. Particularly, making the stuff dance to sound beats isn’t as simple as putting a container of the stuff in front of a speaker coil, but people have discovered a few ways that work more reliably than others.

[Love Hultén]’s drum synth was inspired by this custom Bluetooth speaker with dancing ferrofluid by [Dakd Jung], which drives an electromagnetic coil with frequencies selected from the audio with an MSGEQ7 equalizer. That way, only frequencies that work best for moving the fluid in interesting ways get used for the visualization. The MSGEQ7 spectrum analyzer chip is very useful for music-driven projects, as demonstrated by these sound-reactive LED shades which illustrate the audio element nicely.

The coils that create the electromagnetic field causing ferrofluid to move can take different forms, but two very interesting ones are this 12-layer PCB coil and for more intricate displays, there’s a 12×21 coil array that creates a dot-matrix-like display.

We have one last tip to share about enclosures. Some readers may have noticed that this drum synth project is housed in what looks like a piece of painted lumber. Wood is certainly a versatile material for making custom shapes, and for lettering and labels it turns out that toner transfer works just as well on wood as it does for making custom PCBs.

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It Turns Out Parrots Love Videoconferencing

June 4, 2023 by Donald Papp 18 Comments

A recent experiment showed that parrots seem considerably enriched by the ability to video call other parrots. It’s important that the activity be done in a healthy and ethical way, so researchers do not recommend bird caretakers immediately slap a spare tablet in front of every bird — but the results are as heartwarming as they are encouraging.

Parrots are intelligent creatures known to require and benefit from intellectual and emotional stimulation, and their eyesight is such that they are able to use a display like a tablet screen much like a human would. They are also social creatures, and that led to researchers designing a pilot study to explore a parrot-to-parrot videoconferencing system.

The three-month study showed that when given the opportunity to initiate and receive video calls, every single parrot in the test group did so and all bird caretakers reported perceived benefits. Birds made friends, seemed highly motivated, and even learned behaviors by watching others.

Curious about the details? The published results (a PDF and two brief videos) covers all the bases. Parrot pals may also remember another time that technology enriched a feathered friend with a motorized buggy complete with beak-compatible joystick for steering.

Simple Cubes Show Off AI-Driven Runtime Changes In VR

May 30, 2023 by Donald Papp 6 Comments

AR and VR developer [Skarredghost] got pretty excited about a virtual blue cube, and for a very good reason. It marked a successful prototype of an augmented reality experience in which the logic underlying the cube as a virtual object was changed by AI in response to verbal direction by the user. Saying “make it blue” did indeed turn the cube blue! (After a little thinking time, of course.)

It didn’t stop there, of course, and the blue cube proof-of-concept led to a number of simple demos. The first shows off a row of cubes changing color from red to green in response to musical volume, then a bundle of cubes change size in response to microphone volume, and cubes even start moving around in space.

The program accepts spoken input from the user, converts it to text, sends it to a natural language AI model, which then creates the necessary modifications and loads it into the environment to make runtime changes in Unity. The workflow is a bit cumbersome and highlights many of the challenges involved, but it works and that’s pretty nifty.

The GitHub repository is here and a good demonstration video is embedded just under the page break. There’s also a video with a much more in-depth discussion of what’s going on and a frank exploration of the technical challenges.

If you’re interested in this direction, it seems [Skarredghost] has rounded up the relevant details. And should you have a prototype idea that isn’t necessarily AR or VR but would benefit from AI-assisted speech recognition that can run locally? This project has what you need.

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Mat Boards Are Spendy, So DIY CNC Tool To The Rescue

May 29, 2023 by Donald Papp 22 Comments

Mats are flat pieces of paper-based material that fill the space between a frame and the art within. They perform a number of aesthetic and practical functions, and they can also be expensive to purchase. Making them by hand is an option, but it’s an exacting process. [wooddragon48] felt that a CNC solution would serve this need nicely, and began designing a DIY CNC tool to do exactly that.

One of the tricky parts about cutting mat boards is that cuts are at an angle, and there is really no tolerance for overcuts or any kind of visual blemish. CNC control would seem to offer a great solution to both the need for precisely straight cuts, as well as fine control over where cuts begin and end in a way that opens the door to complex designs that would be impractical to do by hand.

[wooddragon48]’s design has an angled cutter designed to plunge perfectly on demand, surrounded by a ring — similar to that on a router — which ensures the cutting tool is always consistently positioned with the material. It’s still in the design phase, but this is a type of tool that doesn’t yet exist so far as we can tell. The ability to CNC cut mat board, especially in complex designs, would be a huge timesaver.

Art and DIY CNC have a long history of happy intersection, as we have seen with a CNC router repurposed for string art, a CNC painting robot, and even an interactive abstract sculpture generator.

Math Reveals How Many Shuffles Randomizes A Deck

May 28, 2023 by Donald Papp 52 Comments

Math — and some clever simulations — have revealed how many shuffles are required to randomize a deck of 52 cards, but there’s a bit more to it than that. There are different shuffling methods, and dealing methods can matter, too. [Jason Fulman] and [Persi Diaconis] are behind the research that will be detailed in an upcoming book, The Mathematics of Shuffling Cards, but the main points are easy to cover.

A riffle shuffle (pictured above) requires seven shuffles to randomize a 52-card deck. Laying cards face-down on a table and mixing them by pushing them around (a technique researchers dubbed “smooshing”) requires 30 to 60 seconds to randomize the cards. An overhand shuffle — taking sections from a deck and moving them to new positions — is a staggeringly poor method of randomizing, requiring some 10,000-11,000 iterations.

The method of dealing cards can matter as well. Back-and-forth dealing (alternating directions while dealing, such as pattern A, B, C, C, B, A) yields improved randomness compared to the more common cyclic dealing (dealing to positions in a circular repeating pattern A, B, C, A, B, C). It’s interesting to see different dealing methods shown to have an effect on randomness.

This brings up a good point: there is not really any such a thing as “more” random. A deck of cards is either randomized, or it isn’t. If even two cards have remained in the same relative positions (next to one another, for example) after shuffling, then a deck has not yet been randomized. Similarly, if seven proper riffle shuffles are sufficient to randomize a 52-card deck, there is not really any point in doing eight or nine (or more) because there isn’t any such thing as “more” random.

You can watch these different methods demonstrated in the video embedded just under the page break. Now we know there’s no need for a complicated Rube Goldberg-style shuffling solution just to randomize a deck of cards (well, no mathematical reason for one, anyway.)

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