We’re absolutely excited to be able to announce that the Hackaday Supercon is on for 2023, and will be taking place Nov 3 – Nov 5 in sunny Pasadena CA. And with that, we’d like to open the floodgates: we’d like to hear your proposals for talks and workshops! The Call for Speakers and Call for Workshops forms are online now, and you’ve got until July 18th to get yourself signed up.
Clever Optics Make Clock’s Digits Float In Space
If you’ve never heard of Aerial Imaging by Retro-Reflection, or AIRR for short, you’re probably not the only one. It’s a technique developed by researchers at Utsunomiya University that uses beam splitters and retroreflective foil to create the illusion of an image floating freely in the air. Hackaday alum [Moritz v. Sivers] has been experimenting with the technique to make — what else — a clock, appropriately called the Floating Display Clock.
The most commonly available retroreflective films are typically used for things like street signs and high-visibility clothing, but also work perfectly fine for homebrew AIRR setups. [Moritz] tried several types and found that one called Oralite Superlens 3000 resulted in the best image quality. He combined it with a sheet of teleprompter glass and mounted both in their appropriate orientation in a black 3D printed enclosure.
The projected image is generated by a set of 8×8 RGB LED displays, which are driven by a PCA9685 sixteen-channel servo driver board. A Wemos D1 Mini fetches the time from an NTP server and operates the display system, which includes not only the LED panels but also a set of servos that tilt each digit when it changes, giving the clock an added 3D effect that matches nicely with the odd illusion of digits floating in space.
We can imagine it’s pretty hard to capture the end result on video, and the demonstration embedded below probably doesn’t do it justice. But thanks to [Moritz]’s clear step-by-step instructions on his Instructables page, it shouldn’t be too hard to replicate his project and see for yourself what it looks like in real life.
Although this isn’t a hologram, it does look similar to the many display types that are commonly called “holographic”. If you want to make actual holograms, that’s entirely possible, too.
Continue reading “Clever Optics Make Clock’s Digits Float In Space”
A Look Inside A Vintage Aircraft Altimeter
There’s a strange synchronicity in the projects we see here at Hackaday, where different people come up with strikingly similar stuff at nearly the same time. We’re not sure why this is, but it’s easily observable, with this vintage altimeter teardown and repair by our good friend [CuriousMarc] as the latest example.
The altimeter that [Marc] dissects in the video below was made by Kollsman, which is what prompted us to recall this recent project that turned a jet engine tachometer into a CPU utilization gauge. That instrument was also manufactured by Kollsman, but was electrically driven. [Marc]’s project required an all-mechanical altimeter, so he ordered a couple from eBay.
Unfortunately, thanks to rough handling in transit they arrived in less than working condition, necessitating the look inside. For which we’re thankful, of course, because the guts of these aneroid altimeters are quite impressive. The mechanism is all mechanical, with parts that look like something [Click Spring] would make for a fine timepiece. [Marc]’s inspection revealed the problem: a broken pivot screw keeping the expansion and contraction of the aneroid diaphragms from transmitting force to the gear train that moves the needles. The repair was a little improvisational, with 0.5-mm steel balls used to stand in for the borked piece. It may not be flight ready, but it worked well enough to get the instrument back in action.
We suspect that [Marc] won’t be able to leave well enough alone on this one, so we’ll be on the lookout for a proper repair. In the meantime, he’ll be able to use this altimeter in the test setup he’s building to test a Bendix air data computer from a 1950s-era jet fighter. Continue reading “A Look Inside A Vintage Aircraft Altimeter”
WordStar Reborn
Wordstar was the word processor that helped sell the personal computer. At one time, it was ubiquitous, and many authors had a hard time giving it up. Some, like George R. R. Martin, apparently are still refusing to give it up. But most of us have moved on. Thanks to an open-source clone, WordTsar, you may not have to. This is a modern interpretation of our old friend.
Programmers that write were especially fond of WordStar since it had a non-document mode and was often the best text editor you had available for writing code. Being able to do your documentation without switching brain gears is useful, too. Touch typists love the efficiency of easy control of things without resorting to cursor keys or a mouse — the same thing vi and emacs fans enjoy but in a different way.
The software runs on multiple platforms and has some new features. Installation on Linux is easy because it is packaged in an AppImage file. Of course, you can also fire up your best CP/M machine, replica, or emulation and run the real WordStar, but — honestly — WordTsar seems more practical if you wanted to go back to using this kind of wordprocessor or editor for everyday use.
Of course, some word processors were actual hardware. If you want some cheap CP/M hardware, that’s easy enough, too.
Scorched Moon: Secret Project A119
In today’s world, it is hard to realize how frightened Americans were at the news of Sputnik orbiting the Earth. Part of it was a fear of what a rival nation could do if they could fly over your country with impunity. Part of it was simply fear generated by propaganda. While America won the race to the moon, that wasn’t clear in the 1950s. The Soviet Union was ahead in the ability to deliver bombs using planes and missiles. They launched Sputnik on a modified ICBM, while American attempts to do the same failed spectacularly. The Air Force wanted ideas about how to respond to Sputnik, and one of the most disturbing ones was project A119, a project we were reminded of recently by a BBC post.
In all fairness, the Soviets had an almost identical plan, code-named E4. Fortunately, both sides eventually realized these plans weren’t a good idea. Oh, did we forget to mention that A119 and E4 were plans to detonate a nuclear device on the moon?
Tiny Orrery Keeps The Planets In Their Places
[Frans] claims to have made the world’s smallest wooden orrery. We won’t take a position on that — such things are best left up to the good folks at Guinness. But given that the whole thing is seriously in danger of being dwarfed by a USB-C connector, we’d say he’s got a pretty good shot at that record.
The key to keeping this planetarium so petite while making it largely out of wood is to eschew the complex gear trains that usually bring the Music of the Spheres to life in such devices. The layered base of the orrery, with pieces cut from a sheet of basswood using a laser cutter, contains a single tiny stepper motor and just two gears. A zodiac disc sits atop the base and is the only driven element in the orrery; every other celestial body moves thanks to a pin set into the zodiac disc. An ESP32 C3 contacts a NASA feed once a day to get the relative positions of the planets and uses the zodiac disk to arrange everything nicely for the day. The video below shows the “Planet Spinner” in action.
We love the look of this project; the burnt edges and lightly smoked surface of the laser-cut wooden parts look fantastic, and the contrast with the brass wires is striking. We’ve seen an orrery or two around here, executed in everything from solid brass to Lego, but this one really tickled our fancy. Continue reading “Tiny Orrery Keeps The Planets In Their Places”
Making Music By Probing Magnetite Crystals
Well, noises anyway. [Dmitry Morozov] and [Alexandra Gavrilova] present an interesting electronics-based art installation, which probes a large chunk of crystalline magnetite, using a pair of servo-mounted probes, ‘measuring’ the surface conductivity and generating some sound and visuals.
It appears to have only one degree of freedom per probe, so we’re not so sure all that much of the surface gets
probed per run, but however it works it produces some interesting, almost random results. The premise is that the point-to-point surface resistivity is unpredictable due to the chaotically formed crystals all jumbled up, but somehow uses these measured data to generate some waveshapes vaguely reminiscent of the resistivity profile of the sample, the output of which is then fed into a sound synthesis application and pumped out of a speaker. It certainly looks fun.
From a constructional perspective, hardware is based around a LattePanda fed samples by an ADS1115 ADC, which presumably is also responsible for driving the LCD monitor and the sound system. An Arduino is also wedged in there perhaps for servo-driving duty, maybe also as part of the signal chain from the probes, but that is just a guess on our part. The software uses the VVVV (Visual Live-programming suite) and the Pure Data environment.
We haven’t seen magnetite used for this type of application before, we tend to see it as a source of Iron for DIY knifemaking, as a medium to help separate DNA or just to make nanoparticles, for erm, reasons.






