Mysterious Files PH

Meshtastic has gained a lot of popularity over the last few years thanks to its low barrier of entry. No licenses are needed and the hardware is dirt cheap, at least when compared to a lot of ham radio gear. But while that physical barrier is low, there is a bit of a learning curve. Part of that comes from the fact that there are a lot of channels and modes that people could be communicating on, and unless the user knows that information up front it can be hard to find where the conversations are happening. [cemaxecuter] noticed this problem and built a Meshtastic sniffer into his radio-forward Linux distribution, DragonOS.

The sniffing software is built in C and comes as a complete standalone binary and does not rely on GNU Radio. With DragonOS up and running and the software loaded, it can look at the entire bandwidth that Meshtastic operates on and detect any traffic and decode it (as long as the key is known). [cemaxecuter] is using a HackRF as a software-defined radio for this project, which he notes doesn’t quite have enough bandwidth to cover every Meshtastic operating frequency, but it can get most of them. After firing up his own node, the software quickly detects it and shows its details in the terminal.

Software like this opens up a lot of opportunities for things that would be tedious, difficult, or impossible to do with with a standard Meshtastic node. Besides finding places where conversations are happening more easily, [cemaxecuter] also suggests that it could be used for wardriving and for locating or finding other networks much more easily. For those who still haven’t tried it out, take a look at this 2023 treatise on the protocol and hardware and then dive right in.

If you need a micro-manipulator, you probably already have a good idea of what it does. For example, you might be moving a probe over an IC die or wafer. You might be looking at something through a microscope. The key is moving something in very small, precise increments along three axes. An open-source design for a micro-manipulator has seen significant improvements lately. You can see several videos about the device below.

The device uses stepper motors, parallel kinematics, and miniature ball joints to achieve precise motion. The recent version 4.0 update fixes a few problems. According to the GitHub page:

• Self-collision during homing fixed.
• Connection of the ball joint block with screws only was not well constrained and could be rotated a bit.
• No reliable way to ensure consistent linkage rod length
• Unnecessary ball joint friction
• Accurate ball position heavily dependent on print quality and corner rounding
• Rubber bands could not be changed or removed once glued in.

We’ve covered earlier versions of this device, and we were watching the improvements to the ball joints. Since then, the project has updated much of its mechanical design and documentation, and it has also changed the API that drives it. It can even use tools in g-code now to support things like fine control over laser engraving.

If you prefer something old-school manual, consider a 3D-printed one.

Don’t want AI features on your Mac? Tough luck, unless one wants to imperfectly do it by hunting down settings in about a dozen different places. Even then, the multi-gigabyte models stay on disk. Unsatisfied by this state of affairs, [omlahore] created RemoveMacAI, a one-stop-shop debloater that shows Apple Intelligence the door, reclaiming its disk space on the way out.

With RemoveMacAI one has a single location from which to turn individual AI features off, delete the models behind them, and block MacOS from downloading them again by redirecting attempts to a closed local port.

What’s refreshingly nice about the tool is how transparent it is about what each setting or preset will change, and communicates clearly what exactly one loses access to by disabling it. Want it all gone? Easy. Use one or two features, but don’t want the rest? No problem. All changes are shown up-front before the tool changes anything, and all alterations are reversible.

Released only a couple weeks ago, to say the tool is popular would be an understatement. Windows 11 also got a “remove AI features” tool, and it requires constant updating to stay functional. Will a future MacOS update interfere similarly with RemoveMacAI? Probably, but one thing that is clear is that a tool like this resonates deeply with a nontrivial number of users.

While Hackaday doesn’t maintain a crime blotter, we couldn’t help but start this week’s post off with a bit of civil disobedience — a retired professor from the University of Pennsylvania was arrested earlier this week for standing in front of a delivery robot.

Granted, she was standing there for long enough that the police were eventually called, but still. Previous reporting indicates that Carolyn Marvin has a history of blocking delivery robots as a form of protest, but this is the first time law enforcement got involved. We’re not lawyers here at Hackaday, so we can’t say for sure whether or not blocking the progress of a robot engaged in commercial operation actually violates any laws. But we do know that refusing a lawful request from a police officer will get you in trouble, and that seems to be what Marvin was actually charged with when she refused to move.

From a robot stopped in its tracks to one that keeps on trucking, NASA is reporting that the odometer on the Perseverance Mars rover recently ticked over to 28.10 miles (45.22 kilometers). That might not seem like a lot, but it officially makes it the most traveled rover in the solar system, breaking the record set by Opportunity at 28.06 miles (45.16 km). One might expect that the Curiosity rover would hold the distance record as it had been rolling around on the surface for more than a decade before Perseverance dropped into the neighborhood, but the different scientific missions of the two nearly identical rovers have taken them on very different courses.

On the subject of navigation, MapQuest recently announced the availability of the “Surveillance Layer” in their smartphone application. When enabled, it shows the location of known license plate readers and cameras on the map, allowing the user to plan their route accordingly. A note in the application’s user interface mentions that they’re pulling at least some of this data from OpenStreetMap, though it’s not clear currently if other sources such as DeFlock are being used.

Finally, we have an update on the Christie’s auction for the carrier pigeon data packet sent back in 2001 by Norway’s Bergen Linux User Group. The auction house thought the framed datagram might fetch as much as $3,000 USD, but when the hammer finally went down earlier this week the winning bid was a staggering $20,480. Given all the weird gadgets we’ve picked up on a whim, we’re not in a position to lecture anyone else about how they spend their money…but damn.

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.

Refrigeration has been a challenge for humanity since the start. Ancient civilizations in dry climates like Persia and Egypt could use evaporative cooling on a large scale with specialized architecture, and with easy access to electricity modern civilization can cool down almost anything it wants. But whether in a refrigerator or heat pump, the electricity demands can get out of hand quickly, and heat-driven systems often require dangerous or hard-to-get chemicals. But [Greenhill Forge] has crafted a system that creates effective refrigeration with only fire and salt… and a bit of electricity.

Heat-driven systems are called absorption coolers. In this design, water is used as a refrigerant and forced to a very low pressure so that it can boil at a low temperature. When it boils it absorbs heat from the surrounding environment, and then that water vapor can be moved and condensed where it gives off that heat. The build has a few distinct loops to make all of this happen. The generator loop holds the heat source and a tank of water mixed with road salt. Boiled water travels up a tube to a condenser. A valve here is opened slightly to allow the water to drip into the absorber section, where it is under low pressure and boils rapidly. The vapor is carried away by the third system, which uses a shower of the salt solution to quickly suck up the vapor and move it away from the cooled area.

There is a small amount of electricity needed to run pumps and fans, but to keep this off-grid this requirement is easily met by a small solar panel or battery. The bulk of the energy is from the fire which boils the saltwater solution. [Greenhill Forge] added a number of temperature and pressure sensors to monitor and control the system as well, and in his firsts tests the refrigeration system was able to get to about 5° C with an ambient temperature around 16° C. That’s not quite the temperature needed for a refrigerator, but not bad for only salt and fire. [Greenhill Forge] has a number of other ingenious off-grid builds like this sawdust stove and a magnetic induction water heater.

Although for many decades the planet Mars has been prodded, poked, driven upon, flown over and especially orbited by various spacecraft, landers and rovers sent over by a certain humanoid species on Earth, the two moons that orbit Mars have featured significantly more in science-fiction and video games than in scientific literature. This is now about to change when the Martian Moons eXploration (MMX) mission launches on October 19th, which will include a sample return from Phobos.

So far these two moons of Mars – Phobos and Deimos – have only received a few cursory glances by passing spacecraft, leaving many fundamental questions surrounding their formation and composition very much open. With the MMX mission this should change dramatically, with this spacecraft intended to perform detailed measurements of both moons.

In addition a rover – called Idefix – will perform a landing on Phobos for observations of its surface. This will be quite a feat as despite this lander coming in at 25 kg, on Phobos’ surface it will weigh only 15 grams due to the low gravity, or even less than the diminutive dog companion of Obelix, with potential bouncing as we have seen with previous landing attempts on such small bodies.

After launch, the MMX mission will take a year to arrive at Mars, in August of 2027, with Idefix being released in early 2029 for its hopefully soft paws-down on the surface of Phobos where it can scurry about for a while until the main MMX spacecraft lands later for its sample retrieval and return part of the mission. If everything goes well, this would mean that a sample of Phobos should be landing in Australia in 2031.

As electronic components grow ever smaller, a microscope has become an increasingly indispensable tool for any fine work; when inspecting electronics, though, especially solder joints, [Corebb] found a top-down view too limiting, so he built his own microscope with a rotating side-angle view.

The microscope itself is made of a commercial C-mount microscope lens assembly and a USB camera; the lens has a variable magnification factor up to 200x, which is plenty for electronics work, and is mounted on an adjustable stand to move the focal point. This is paired with an LED ring for illumination and two polarizing filters, one mounted on the lens and one one the lighting ring; when adjusted to 90 degrees from each other, these eliminate glare from reflective surfaces.

To view subjects from the side, [Corebb] built a snap-on adapter. This uses a pair of mirrors to capture a view from the side of the object and direct this through the main microscope lens. An additional concave lens compensates for the increased length of the optical path, and ball bearings let the whole adapter rotate around the microscope and capture the subject from any angle. [Corebb] tried 3D-printing the adapter, but found that flexing caused too much jitter; in addition to being sturdier, a machined aluminium part reduced shadows by allowing for thinner supports. The adapter snaps onto the microscope with small magnets, which keep the optical path consistently aligned.

This isn’t the first time we’ve seen a soldering microscope with a view from the side, but this does look much more affordable. If you’d like to try the polarized light source with your microscope, we’ve covered that before.