Iridescent Rainbow Chocolate, Just Add Diffraction Grating!

Chocolate plus diffraction grating equals rainbow chocolate

Here’s a great picture from [Jelly & Marshmallows] that shows off the wild effects of melted chocolate poured onto a diffraction grating. A diffraction grating is a kind of optical component whose micro-features act to disperse and scatter light. Diffraction gratings are available as thin plastic film with one side that is chock full of microscopic ridges, and the way light interacts with these ridges results in an iridescent, rainbow effect not unlike that seen on a CD or laserdisc.

It turns out that these micro-ridges can act as a mold, and pouring chocolate over a diffraction grating yields holo-chocolate. These photos from [Jelly & Marshmallows] show this effect off very nicely, but as cool as it is, we do notice that some of the letters seem a wee bit hit-or-miss in how well they picked up the diffraction grating pattern.

Fortunately, we know just what to suggest to take things to the next level. If you want to know more about how exactly this effect can be reliably accomplished, you’ll want to check out our earlier coverage of such delicious optics, which goes into all the nitty-gritty detail one could ever want about getting the best results with either melted sugar, or dark chocolate.

Artwork Spans Fifty Years Of Display Technology

Swiss artist and designer [Jürg Lehni] was commissioned to create an artwork called Four Transitions which has been installed in the HeK (House of electronics Arts) in Basel. This piece visually depicts the changes in technologies used by public information displays, such as those in airports and train stations. As the title of the installation suggests, four different technologies are represented:

  • Flip-Dot, early 1960s, 15 each 7 x 7 modules arrayed into a 21 x 35 pixel panel
  • LCD, 1970s and 1980s, two each 36 x 52 modules arrayed into 52 x 76 pixel panel
  • LED, 2000s, six each 16 x 16 RGB modules arrayed into a 32 x 48 pixel panel
  • TFT, current, one 24 inch module, 1200 x 1920 pixel panel

The final work is quite striking, but equally interesting is the summary of the the design and construction process that [Jürg] provides on Twitter. We hope he expands this into a future, more detailed writeup — if only to learn about reverse engineering the 20 year old LCD controller whose designer was in retirement. His tweets also gives us a tantalizing glimpse into the software, controllers, and interconnections used to drive all these displays. There is quite a lot of interesting engineering going on in the background, and we look forward to future documentation from [Jürg].

You may recognize [Jürg] as the creator of Hektor, a graffiti output device from 2002 which we’ve referenced over the years in Hackaday. Check out the short video below of the displays in operation, and be sure to unmute the volume so you can listen to the satisfying sound of 735 flip-dots changing state. [Jürg] also gives in interview about the project in the second video below. Thanks to [Niklas Roy] for sending in the tip about this most interesting exhibition.

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Improved Graphics-to-Drawing Tablet Conversion

[Akaki Kuumeri] had an old Wacom Intuos digitizing graphics tablet collecting dust, and figured out how to non-destructively transform it into a drawing tablet. He was inspired by an old Hackaday post of a similar hack, but it required literally hacking a big hole into your Wacom tablet. Not wanting to permanently ruin the Wacom tablet,  [Akaki] instead designed a 3D printed frame which he holds in place with a pair of straps. The design files are available on Thingiverse. He names the project, incorrectly as he later points out, WacomOLED (it rhymes with guacamole, we think).

As for the screen, he buys an old third-generation iPad and removes its Retina display panel and the foil backing, which would otherwise block the stylus’s connection to the tablet. Toss in an HDMI driver board to connect the display to your computer, and presto — you have made your own a drawing tablet. Even if you don’t need a drawing tablet, [Akaki]’s hack is still interesting, if only to remind us that we can put custom HDMI displays into any project for $65 using this technique.

In the end, [Akaki] notes that unless you already have a non-graphical digitizing tablet laying around, it’s probably cheaper to just buy a iPad. This is not [Akaki]’s first go at user input devices — we wrote about his Smash Brothers game controller and flight controller yoke project last year.

Do any of you use a graphics tablet in your day to day workflow? Let us know in the comments below.

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Julius Sumner Miller Made Physics Fun For Everyone

Let’s face it — for the average person, math and formulas are not the most attractive side of physics. The fun is in the hands-on learning, the lab work, the live action demonstrations of Mother Nature’s power and prowess. And while it’s true that the student must be willing to learn, having a good teacher helps immensely.

Professor Julius Sumner Miller was energetic and enthusiastic about physics to the point of contagiousness. In pictures, his stern face commands respect. But in action, he becomes lovable. His demonstrations are dramatic, delightful, and about as far away from boring old math as possible. Imagine if Cosmo Kramer were a physics professor, or if that doesn’t give you an idea, just picture Doc Brown from Back to the Future (1985) with a thick New England accent and slightly darker eyebrows. Professor Miller’s was a shouting, leaping, arm-waving, whole-bodied approach to physics demonstrations. He was completely fascinated by physics, and deeply desired to understand it as best he could so that he could share the magic with people of all ages.

Professor Miller reached thousands of students in the course of his nearly 40-year teaching career, and inspired millions more throughout North America and Australia via television programs like The Mickey Mouse Club and Miller’s own show entitled Why Is It So? His love for science is indeed infectious, as you can see in this segment about the shock value of capacitors.

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Faux Stained Glass Effect, With 3D Printing And Epoxy

Like the looks of stained glass, but not the amount of work, skill, and materials involved? Well, [Northern Geometry] shows how to sidestep all that nonsense and use a 3D printed frame, epoxy, and some alcohol-based inks to create a pretty good fake stained-glass effect piece of art.

A smooth polypropylene board is the key to a glassy smooth back.

[Northern Geometry] has played with this idea before, but shares some refinements and tips on getting the best results. One suggestion is to begin by securely taping the 3D printed frame to a smooth polypropylene board as a backer. Giving the cured resin a smooth surface is important to get the right look, and since resin will not bond to the polypropylene, it can be used as a backer to get that done.

Once the frame is mounted, pour a small amount of epoxy into each cavity and ensure it gets into every corner, then let it cure. The thin bottom layer of resin will seal things as well as create a glassy-smooth backing that is the perfect foundation for finishing the piece with colored resin as needed.

Once that is done, and everything has had plenty of time to cure fully, just pop the piece off the board. Check it out in the video embedded below, where [Northern Geometry] shows the process from start to finish.

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A HALO Of LEDs For Every Ear

Few things get a Hackaday staffer excited like bunches of tiny LEDs. The smaller and denser the better, any form will do as long as we can get a macro shot or a video of a buttery smooth animation. This time we turn to [Sawaiz Syed] and [Open Kolibri] to deliver the brightly lit goods with the minuscule HALO 90 reactive LED earrings.

The HALO 90’s are designed to work as earrings, though we suspect they’d make equally great brooches, hair accessories, or desk objects. To fit this purpose each one is a minuscule 24 mm in diameter and weighs a featherweight 5.2 grams with the CR2032 battery (2.1 g for the PCBA alone). Functionally their current software includes three animation modes, each selectable via a button on device; audio reactive, halo (fully lit), and sparkle. Check out the documentation for details on expected battery life in each mode, but suffice to say that no matter what these earrings will make it through a few nights out.

In terms of hardware, the HALO 90’s are as straightforward as you’d expect. Each device is driven by an STM8 at its maximum 16MHz which is more than fast enough to keep the 90 charliplexed 0402 LEDs humming along at a 1kHz update rate, even with realtime audio processing. In fact the BOM here is refreshingly simple with just 8 components; the LEDs, microcontroller and microphone, battery holder and passives, and the button. [Sawaiz] even designed an exceptionally slick case to go with each pair of earrings, which holds two HALO 90’s with two CR2032’s and includes a magnetic closure for the most satisfying lid action possible.

As with some of his other work, [Sawaiz] has produced a wealth of exceptional documentation to go with the HALO 90’s. They’re available straight from him fully assembled, but with documentation this good the path to a home build should be well lit and accessible. He’s even chosen parts with an eye towards long availability, low cost, and ease of sourcing so no matter when you decide to get started it should be a snap.

It was difficult to choose just a few images from [Sawaiz]’s mesmerizing collection, so if you need more feast your eyes on the expanded set after the break.

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Portrait Of A Digital Weapon

Over the years, artists have been creating art depicting weapons of mass destruction, war and human conflict. But the weapons of war, and the theatres of operation are changing in the 21st century. The outcome of many future conflicts will surely depend on digital warriors, huddled over their computer screens, punching on their keyboards and maneuvering joysticks, or using devious methods to infect computers to disable or destroy infrastructure. How does an artist give physical form to an unseen, virtual digital weapon? That is the question which inspired [Mac Pierce] to create his latest Portrait of a Digital Weapon.

[Mac]’s art piece is a physical depiction of a virtual digital weapon, a nation-state cyber attack. When activated, this piece displays the full code of the Stuxnet virus, a worm that partially disabled Iran’s nuclear fuel production facility at Natanz around 2008. Continue reading “Portrait Of A Digital Weapon”