TechyMagThings

As great as echolocation is, things can get rather messy once it’s not just you chirping away, but also hundreds of your buddies in roughly the same area. This is the scenario that the typical colonies of bats have to deal with. In a recent study by [Haruhito Matsumoto] et al. in Journal of Comparative Physiology they investigated how colonies of greater Japanese horseshoe bats deal with this issue.

Echolocation in animals can use a variety of methods, including frequency modulation (FM, varying the pitch) or constant frequency (CF), with both having their uses during hunting as well as obstacle avoidance. One big advantage of CF is that it can be used for Doppler shift, giving very precise information about location and velocity of objects in the environment, but if used in a busy colony the acoustic interference would effectively render them blind.

What researchers have found is that the CF component frequencies differ per bat colonies, with the mixing of wild-caught and resident horseshoe bats in this experiment showing them adjusting the dominant second harmonic (CF2) to match, with bats using a lower frequency CF2 adjusting it upwards. In this way frequency convergence is used as a strategy to avoid acoustic interference using a so-called ‘silent spectral window’.

As this spectral window for effective Doppler tracking is found above the CF2 frequency, it therefore makes sense that the bats at a lower CF2 harmonic would adjust their CF upwards to match that of their neighbors. Although more research is required to fully confirm these findings, it sheds some more light on the use of echolocation by these amazing flying mammals.

As easy as the Sun is to observe, it’s simultaneously very hard to study due to how extreme the conditions are, even on the surface of a rather unassuming star. One of these study topics is the interaction between the Sun’s plasma and magnetic field, as this drives much of the dynamism of the Sun’s surface layer (i.e., the photosphere). Recent observations by the 4-meter solar telescope in Hawaii have now led to interesting new findings, as detailed in a paper in Nature by [David Kuridze] et al.

Despite popular portrayal, this photosphere is not a boiling liquid, but rather pockets of plasma at various temperatures. The plasma moves within the magnetic field and convective movements that create the ‘boiling’ pattern, which gives the illusion of a boiling liquid surface.

Within this photosphere, [Kuridze] et al. were able to observe Kelvin-Helmholtz instabilities, which are fluid instabilities caused by velocity shearing in either a continuous fluid or due to a velocity difference between two fluids. This is also observed in clouds in Earth’s atmosphere, where they cause the billowing effect, somewhat similar to watching a boiling liquid.

In a MURaM simulation (see heading image), these findings were confirmed, showing how these instabilities drive the transport of plasma in the Sun’s photosphere.

Once upon a time, you had the option of waking up to a bell, a harsh buzzer, or whatever happened to be on the radio that morning. Now that it’s the 21st century, we’ve gotten used to being able to set our alarms to whatever sound or song we want, but what if you don’t just want to wake up to sound? Enter [Impossible_Agent1436] a.k.a. [brunokeymolen]’s Video Alarm Clock that will wake you up to whatever clip you want, as long as it fits on the 720 pixel square display.

That display is a pre-built Waveshare module powered by an ESP32-P4, which looks like a handy bit of kit aside from being out of stock at the moment. The dev board makes this almost entirely a software project– the only hardware [bruno] had to come up with was the 3D-printed stand to hold it on his bedside. That’s not a slight to [bruno]; it was a good choice in the spirit of “work smarter, not harder”. Sometimes you want to reinvent the wheel, and sometimes you just want an alarm clock.

The module’s RTC means it keeps good time, and the built-in SD card reader means you can load up a whole library of clips to wake up to. The only caveat is that those files have to be AVI containers holding 720×720 MJPEG video with PCM stereo audio at 44.1 kHz, and you’re limited to old FAT filename rules: eight characters, and none of them special.

This is an easier project and a better idea than the exploding capacitor alarm clock, but there’s no arguing which would get us out of bed faster. If you miss the old days of clock radios, you can always bring them back with the right microcontroller.

Story via reddit.

The earliest all-electronic computers used vacuum tubes, and most of us will know about machines such as ENIAC or Colossus. Vast machines that required the budget of a country at war to build, andfill very large rooms. It’s very pleasing then to see that a useful vacuum tube computer can be made which has neither of these requirements, as with this example from [Mike] that uses former eastern bloc double-triodes.

It’s an 8-bit design following a von Neumann architecture with 16 instructions, whose operational block diagram would be instantly recognisable to anyone used to working with a 1970s-era 8-bit microcomputer. It follows a NOR-based design in the same manner as the famous NASA machines from the Apollo programme, and as we understand from the description it uses more modern parts for its I/O circuitry. Physically it’s a surprisingly compact wall-mounted unit, and it has an accompanying ex-British Rail flip-digit display as well as a control panel for a simple airship simulator game. There’s a website with full details, if you are interested.

We like this machine, a lot. It may not be the largest computer we’ve seen and it certainly isn’t the first one with vacuum tubes, but it’s a very impressive achievement to have created it. If tubes in computing interest you meanwhile, we took a trip to see the daddy of them all.

Should [Mike] enter this into the Retrocomputing Challenge? We think so.

Air traffic visualizers seem to be having a bit of a moment right now, and now that moment has come to the venerable NES thanks to [k6lcm]’s NES Radar project, which is open-source under the GPL on GitHub. In spite of the name, there’s no Radio Direction or Range-Finding involved in this project– no radio at all, in fact, which makes this a bit interesting. It’s just an NES cartridge and a carefully constructed cable.

The cartridge is a standard ROM cart that holds the software — no hidden ESP32 or PicoW here, which is what we initially suspected the project would be. So how is it that when you start up the NES with the cartridge inside, you can input an International Civil Aviation Organization (ICAO) code, like, say, KATL, and get a visualization of the traffic? Well, okay, if you put in KATL, you won’t get all the traffic, since the software is limited to 8 sprites, and that’s the world’s busiest airport. Still, how does it know where those airplanes are?

The secret is in the carefully constructed cable mentioned above: this project is using the second controller port on the NES as a serial port, and getting the data that way. A handy Python script on a nearby computer is what actually fetches aircraft positions. It’s based on c64u-radar, also by [k6lcm], which does the same Python server trick but relies on the Commodore 64 Ultimate’s LAN port to get data rather than using serial. The NES has no such ports available, though, so the controller port it was. We saw a similar trick used for satellite tracking on the NES some years ago.

If you like the idea of tracking flights, perhaps you’d like to see it done on a real radar CRT, or projected directly onto the ceiling. Thanks to ADS-B and free APIs, it seems airplane trackers are everywhere; if an interesting one has come onto your radar, please send us a tip.

Speaking of tips, thanks to [Levi] for putting this one on our scopes!

Generally, we do not look at the gentle patter of raindrops on a surface with much concern, but according to a study by [Zhongyuan Ni] et al. in Nature, we should probably regard these droplets with a little scrutiny for their corrosion potential. What they found is that these drops can gather a significant electric potential as they gently slide down a surface, with over 1 kV measured. By first having droplets charge up on an insulating surface before hitting a target metal surface, they were able to induce significant corrosion.

Despite the target metal surface being coated with a protective layer, these charged droplets managed to gradually break down the coating, exposing the bare metal. In this example, a Teflon coating was used, with water droplets containing a small amount of dissolved sodium chloride to simulate natural raindrops.

It was postulated that this causes dielectric breakdown of the insulating protective coating, as the charged water drop acts as one electrode and the — often grounded — metal surface as another electrode. Subsequent investigations on the samples showed that this appears to be indeed the case.

A potential defense here would be to discharge any water before it can reach sensitive surfaces, but it’s not a straightforward problem to solve. As noted in the study’s conclusion, charged droplets can also be generated in clouds and waves, in addition to the insulating materials demonstrated in the study. It’s also a phenomenon that can cause issues anywhere charged droplets occur, such as in a wide range of industrial processes.

If you’re interested in the electrical generating properties of falling water, check out Lord Kelvin’s Generator! Hackaday’s own [Steven Dufresne] explored this phenomenon a few years back.

Yesterday, Isar Aerospace secured its place in the history books when the upper stage of their Spectrum rocket put a payload of CubeSats into low Earth orbit (LEO). Not only does this make them the first European company to achieve such a feat, but it also marks the first time a booster departing from continental Europe has reached orbit. Not bad for a second attempt.

Standing 28 meters (92 feet) tall, the two-stage Spectrum rocket is just shy of half the size of the SpaceX Falcon 9 and designed to put a maximum of 1,000 kilograms (2,200 pounds) into LEO and 700 kg (1,500 lb) into the Sun-synchronous orbits used by Earth observation satellites. That puts its performance considerably ahead of other commercial launchers such as Rocket Lab’s Electron. Although the booster is not reusable, Isar Aerospace has stated they’re targeting a respectable launch cost of €10,000 ($11,700) per kilogram. The German company notes there are several more Spectrum vehicles currently in production, and when their new factory is operational, they’ll have the capacity to produce up to 40 of them each year.

In other European space news, BepiColombo has now entered what the European Space Agency (ESA) is calling the “arrival phase” of its nearly decade-long journey to Mercury. On Thursday, the spacecraft jettisoned its ion propulsion module as it had achieved the necessary trajectory and velocity to be captured by the planet’s gravitational field when it swoops by in November.

Launched in 2018, the BepiColombo mission is actually carrying two separate craft: the ESA’s Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter from Japan. After the two separate from each other in December, they will operate independently to study their respective aspects of the solar system’s innermost planet for the next year, although, as is often the case for missions like this, an extension is always possible if things are still going well at that point.

On the subject of hardware outliving its original design lifetime, an active community of hackers has done a fantastic job of keeping the Spotify Car Thing up and running after the company officially pulled the plug on it just two years after its 2022 release. They’ve got a full Linux distribution running on it featuring a slick UI that can launch apps, check the weather, tap into Home Assistant, and of course, play music. The community is currently running a contest with cash prizes to spur on development of new open source software for the liberated Car Thing, and we’re eager to see what comes of it.

Speaking of keeping things open, the Free Software Foundation (FSF) has joined Bluesky — but they aren’t exactly thrilled with it. Being federated and largely comprised of free and open-source software, the FSF admits that Bluesky is the lesser evil when compared to something like X or Facebook. But they still can’t recommend others join the service, as the actual signup process requires your browser to run non-free JavaScript code.

One may wonder why the FSF would join Bluesky if they can’t recommend the service to others, and the answer is simply because they want to get the word out to a wider audience. While the FSF already operates an account on Mastodon, there’s a good chance that anyone who’s willingly regularly using said platform doesn’t need any additional convincing when it comes to the evils of proprietary software.

This is as good a time as any to point out that Hackaday is on Bluesky and Mastodon as well, and unlike the FSF, we’re also on Facebook, although the automatic sharing of new posts hasn’t worked for quite some time and honestly we can’t be bothered to figure out why. For our readers with a particular aversion to grass, we’ve even got an official IRC channel on libera.chat where you and nearly 50 others can feel superior to the thousands of immoral heathens that have joined our Discord server.

Finally, it’s been 50 years since the introduction of the ColorChecker — that little card with 24 blocks of colors that’s placed in the frame of a picture or video to provide a visual reference point. In honor of the milestone, Calibrite has put together a timeline that walks you through its history, starting with its inception in the 1976 paper “A Color-Rendition Chart” by C.S. McCamy, H. Marcus, and J.G. Davidson and running up to how the handy tool evolved for the digital age.

There are plenty of facts and trivia about the ColorChecker that you can bring up the next time you want to impress a photographer, and we especially appreciated the breakdown of what each of the original 24 colors was meant to represent.

See something interesting that you think would be a good fit for our weekly Links column? Drop us a line; we’d love to hear about it.