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Gli ultimi otto messaggi ricevuti dalla Federazione
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X-Cube Prism Becomes Dichoric Disco Ball
You’ve likely seen an X-cube, a dichoric prism used to split light into its constituent colours–you know, those fun little cubes you get when tearing apart a broken projector. Have you considered that the X-cube need not be a cube for its entire existence? [Matt] at “Matt’s Corner of Gem Cutting” on YouTube absolutely did, which is why he ground one into a 216-facet disco ball.
That’s the hack, really. He took something many of us have played with at our desks thinking “I should do something cool with this” and… did something cool with it that most of us lack the tools and especially skills to even consider. It’s not especially practical, but it is especially pretty. Art, in other words.
The shape he’s using is known specifically to gemologists as “Santa’s Little Helper II” though we’d probably describe it as a kind of isosphere. Faceting the cube is just a matter of grinding down the facets to create the isosphere, then polishing them to brilliance with increasingly finer grit. This is done one hemisphere at a time, so the other hemisphere can be safely held in place with the now-classic cyanoacrylate and baking soda composite. Yes, jewelers use that trick, too.
We were slightly worried when [Matt] dumped his finished disco ball in acetone to clean off the cyanoacrylate– we haven’t the foggiest idea what optical-quality glue is used to hold the four prisms of an X-cube together and were a little worried acetone might soften the joints. That turned out not to be an issue, and [Matt] now has the most eye-catching sun-catcher we think we’ve ever seen.
We actually have seen suncatchers before, though admittedly it’s not a very popular tag around here. The closest build to this one was a so-called “hypercrystal” that combined an infinitiy mirror with a crystaline shape and dicloric tape for an effect as trippy as it sounds.
We also featured a deep-dive a while back if you want to know how these colourful, hard-to-pronounce coatings work.
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Former Minnesota Gov. Jesse Ventura suggests his state join Canada. https://www.nydailynews.com/2026/01/28/fomer-governor-jesse-ventura-wants-minnesota-to-secede-join-canada/
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@ed TheMovieDatabase (TMDB)? https://www.themoviedb.org/
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Light Following Robot Does It The Analog Way
If you wanted to build a robot that chased light, you might start thinking about Raspberry Pis, cameras, and off-the-shelf computer vision systems. However, it needn’t be so complex. [Ed] of [Death and the Penguin] demonstrates this ably with a simple robot that finds the light the old-fashioned way.
The build is not dissimilar from many line-following and line chasing robots that graced the pages of electronics magazines 50 years ago or more. The basic circuit relies on a pair of light-dependent resistors (LDR), which are wrapped in cardboard tubes to effectively make their response highly directional. An op-amp is used to compare the resistance of each LDR. It then crudely steers the robot towards the brighter light between turning one motor hard on or the other, operating in a skid-steer style arrangement.
[Ed] then proceeded to improve the design further with the addition of a 555 timer IC. It’s set up to enable PWM-like control, allowing one motor to run at a lower speed than the other depending on the ratio between the light sensors. This provides much smoother steering than the hard-on, hard-off control of the simpler circuit. [Ed] notes that this is about the point where he would typically reach for a microcontroller if he hoped to add any additional sophistication.
In an era where microcontrollers seem to be the solution to everything, it’s nice to remember that sometimes you can complete a project without using a processor or any code at all. Video after the break.
youtube.com/embed/ikTkOXu1th4?…
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"OK, Google. Navigate to Osaka Grill."
There is a restaurant named "Osaka Grill" that is 11 minutes away from my home.
There is a restaurant named "Osaka" that is 29 minutes away from my home.
Before Gemini, Google Assistant was smart enough to figure out that I meant the place with the stated name that is closer to me, not the place with a similar name that is farther away.
The more AI they add, the dumber it gets.
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In a pagan folk band AND a pagan metal band? I have doubts about Biko.
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I think one of the things I like about this show is that I enjoy planning and preparing for trips (or any activity, really) possibly more than I enjoy the trip itself. Planning for a survival situation? 🤌
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@aeva Put the ubuntu iso image on a usb key and insert it into the computer is all it takes, should be similar on other distros.
netboot.xyz is nice. It's a bootable image which brings up a menu of linux distros to try or install, fetching them over the internet. Install it on a usb key, boot drive, or network boot file.
