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Hackaday Links: June 23, 2024

23 Junio 2024 at 23:00
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When a ransomware attack targets something like a hospital, it quickly becomes a high-profile event that understandably results in public outrage. Hospitals are supposed to be backstops for society, a place to go when it all goes wrong, and paralyzing their operations for monetary gain by taking over their information systems is just beyond the pale. Tactically, though, it makes sense; their unique position in society seems to make it more likely that they’ll pay up.

Which is why the ongoing cyberattack against car dealerships is a little perplexing — can you think of a less sympathetic victim apart from perhaps the Internal Revenue Service? Then again, we’re not in the ransomware business, so maybe this attack makes good financial sense. And really, judging by the business model of the primary target of these attacks, a company called CDK Global, it was probably a smart move. We had no idea that there was such a thing as a “Dealer Management System” that takes care of everything from financing to service, and that shutting down one company’s system could cripple an entire industry, but there it is.

Water may seem like the enemy for anyone who gets in trouble while swimming, but it’s really time that they’re fighting. Even a strong swimmer can quickly become exhausted fighting wind and waves; add in the hypothermia that’ll eventually set in even in water as warm as a bath, and the difference between life and death can come down to seconds. Getting help to a floundering swimmer isn’t easy, though, as lifeguards can only swim so fast.

But a new remotely operated rescue boat aims to change that, by getting to someone in trouble as fast as possible. Named EMILY, for “Emergency Integrated Lifesaving Lanyard,” the unit is a compact electrically powered rescue boat that can be rapidly deployed by lifeguards, who remotely pilot it to the victim. The boat’s deck is covered with what looks like survival gear, most of which would probably be of more use to the lifeguard upon their arrival than to the swimmer, who would likely just use the boat for flotation. As such, this makes way more sense than sending a drone out there, which at best could only drop a life ring. At $12,000 a piece, these boats aren’t cheap, but for the families who lost their kids in 2022 who donated them, they probably seem like quite a bargain. Here’s hoping they pay off.

We can’t be sure, but we’ve got a vague memory of playing a game called Lunar Landing way back in the day. It would likely have been on a TRS-80 in our local Radio Shack store, and if memory serves, we never got particularly good at the text-based simulator. Happily, though, we can now at least attempt to foist our lack of skills off on a 55-year-old bug in the software. Recently discovered by the excellently named Martin C. Martin while trying to optimize the fuel burn schedule to land softly with the most fuel remaining — the key to a high score, as we recall — the bug makes it so a tiny change in burn rate gives wildly different results. The post-mortem of his search and the analysis of the code, written by high school student Jim Storer only months after the real moon landing in 1969, is very interesting. We especially appreciated the insights into how Storer wrote it, revealed via personal communications. It’s a great look at a piece of computer history, and hats off to both Storer and Martin — although we haven’t seen a CVE posted for this yet.

We know that Minitel terminals are highly collectible, but this is ridiculous. Granted, the Minitel occupies a unique place in computer history, and the boxy design of the original CRT and keyboard terminal was not without its charms. But this particular terminal seems to have had a Very Bad Day in the recent past and is now on the chopping block for a mere €430. To be fair, the eBay user in France has listed the Dalí-esque Minitel as an objet d’art; at that price, we’d like to at least get some usable parts from it to fix other terminals, but that doesn’t seem likely. Somebody will probably buy it, though — no accounting for taste.

And finally, AnimaGraffs is back, this time with a deep dive into the Bell 407 helicopter. We’ve been big fans of his work for a while and have featured a few of his videos in this space, including his look inside the SR-71 Blackbird spy plane. The new video is richly detailed and includes not only the engineering that goes into rotorcraft but also the physics that makes them work and makes them so challenging to fly. Enjoy!

Peeking Underground With Giant Flying Antennas

Por: Lewin Day
21 Mayo 2024 at 14:00

Helicopters are perhaps at their coolest when they’re being used as flying cranes — from a long dangling cable, they can carry everything from cars, to crates, to giant hanging saws.

What you might find altogether more curious are the helicopters that fly around carrying gigantic flat antenna arrays. When you spot one in the field, it’s not exactly intuitive to figure out what they’re doing, but these helicopters are tasked with important geological work!

Looking Down From Above

The SkyTEM survey system is one of the most well known in the AEM space. Credit: Geoscience Australia

In the popular imagination, the Earth’s magnetic field is useful for finding north with a compass. In day to day life, that barely comes up, and we don’t give the magnetic field much thought beyond that. However, the reality of Earth’s magnetic field is that it is variable all over the surface of our planet. By measuring it, we can gain great insight into what lies beneath our feet.

Magnetic surveys are an important tool in geology and archaeology. In the latter regard, they were perhaps best popularized by the TV show Time Team. The series would often employ geomagnetic surveys to discover artifacts or structures beneath the ground. The typical technique used on the show involved someone walking around a site with a magnetometer while logging the magnetic field strength as they went. By running the magnetometer in a grid pattern across a site, it was possible to build up a local map of the magnetic field, which could reveal anomalies lurking underground.

That’s all well and good if you wish to survey a small garden or perhaps a single field. If you want to survey a larger area, though, doing a survey on foot isn’t really practical. But you can apply the same techniques in the air at speed, and you can even extend them further, too!

You can do magnetic surveys much faster using a helicopter instead. The basic theory is the same, carrying a magnetic sensor over terrain allows the measurement of the local magnetic field. The difference is that a helicopter can move much faster and thus cover a greater area more quickly, albeit at somewhat reduced resolution. Magnetic field data is great, but there’s so much more that can be gained by exploring the electromagnetic spectrum, too.

A typical setup for helicopter-based geomagnetic surveys. To work at low frequencies, large antennas are needed. This rig transmits at a base frequency of just 25 Hz. Credit: Geoscience Australia Operations & Processing report

By transmitting radio waves from a giant antenna, it’s possible to excite eddy currents in the ground itself which can then be picked up by a sensitive receiver similarly dangling from the aircraft. A single aerial survey aircraft can carry both magnetic sensors and EM equipment on the same mission to gather both kinds of data at once.

Aerial electromagnetic surveys (AEM), as they are known, aren’t so much used for finding Roman coins or small structures under the ground. Instead, they’re used to better understand the makeup of the ground itself. An aerial survey can reveal electrically conductive materials in the ground, of which there are many.

Graphite, clays, sulfides, or salty groundwater all show up differently on an electromagnetic survey compared to non-conductive minerals or fresh water. These elements can be revealed by an antenna dangling from a helicopter, in combination with other geological data and careful analysis.

The Yarrabubba impact structure is the oldest known planetary impact structure on Earth. While much of the original crater has been eroded, the impact has left an anomaly that is readily visible on aeromagnetic surveys to this day. Credit: Erickson, Kirkland, Timms, Cavosie & Davison, CC-BY 4.0

Typical AEM missions involve flying at moderate speeds of 70 to 120 km/h along the ground, generally on a path of parallel lines to cover a given area. Altitudes are low, on the order of 100 meters or even less, to keep the antennas close to the ground. Excitation and receiver antennas usually measure tens of meters in diameter. AEM surveys can be remarkably sensitive. It’s possible to pick up variations in the conductivity of the soil up to several hundred meters deep with the right equipment. As you might expect, the local ground composition plays a role in what’s possible, too.

Often, an aerial study is designed to zero in on a particular geological feature or material of interest. Then, the survey area and equipment can be tuned to ideally reveal the expected contrast in conductivity or magnetic field.

Governments and private enterprises using the technique more commonly than you might think. For example, the California Department of Water Resources uses AEM surveys to hunt for underground aquifers. might be using an AEM survey to find an underground aquifer, or a conductive graphite seam deep in the ground.  The US Geological Survey uses the technique for all kinds of purposes, and has been doing so since the 1970s. It has looked for subsurface water and underground minerals, amongst other things. There’s an interactive tool for finding survey data, much of which is available to the public.

There is a great deal of mistrust in the wider public these days, with conspiracies around chemtrails, 5G cellular networks, and so many other similar topics. It won’t shock you to know that there are people that freak out when they see a helicopter hauling a gigantic antenna array at low altitude.

A conductivity survey reveals groundwater beneath the surface at Mt Saint Helens. Credit: USGS

For this reason, many government agencies specifically release documents to explain the purpose of AEM surveys, and to highlight that they pose no risk to the public, wildlife, or the natural environment itself. It may seem silly, but AEM survey craft do look a fair bit more sci-fi than most other flying vehicles, so the cautious approach is understandable.

You probably won’t spot an AEM survey craft in the suburbs, but if you’re out in some wide open natural area, you just might. If you’re really keen on seeing one in the flesh, though, you’re best advised to get yourself a geology degree and a job in the field. Then, you might even pick up the skills necessary to specify, execute, and interpret the results of an electromagnetic aerial survey. When you do, be sure to let the world know what you found out!

3D Print a Drill-Powered Helicopter Toy Because It’s Simply Fun

Por: Lewin Day
14 Mayo 2024 at 20:00

These days, you can get a fully remote-control helicopter that you can fly around your house for about $30. Maybe less. Back in the day, kids had to make do with far simpler toys, like spinning discs that just flew up in the air. [JBV Creative] has built a toy just like that with his 3D printer. It may be simple, but it also looks pretty darn fun.

The design is straightforward. It uses a power drill to spin up a geartrain, which in turn drives a small disc propeller. Spin the propeller fast enough and it’ll launch high into the air. The geartrain mounts to the drill via the chuck, and it interfaces with the propeller with a simple toothed coupler. Alternatively, there’s also a hand-cranked version if you don’t have a power drill to hand.

Launching is easy. First, the drill spins the propeller up to speed. Then, when the drill’s trigger is released, it slows down, and the propeller spins free of the toothed coupler, with the lift it generates carrying it into the sky.

Files are available online for those interested. We could imagine this toy could make the basis for a great design competition. Students could compete to optimise the design with more effective gear ratios or better airfoils. We’ve seen similar designs before, too. Video after the break.

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