Broadcasting GPS On The Local Network To Help Geoclue Find You

Rather than having users go through the inconvenience of having to punch in their current location, an increasing number of applications and websites use location services that can pin-point the current location of a user to within a certain number of meters or kilometers.

Unfortunately, [Evert Pot] found that with the demise of the Mozilla Location Service (MLS) in 2024, accuracy of the Linux Geoclue service had dropped to a resolution of about 25 km. Since a LAN tends to not move around a lot, this seemed like the perfect time to help Geoclue out with a local GPS server.

All that Geoclue looks for on the LAN is an mDNS service identifying as _nmea-0183._tcp that responds with the GPS coordinates as network packets containing an ASCII payload encoded using the NMEA 0183 standard. With this knowledge [Evert] was then able to quickly put together a Python-based server that simply blasts the static GPS coordinates of the LAN in question.

With the service running, Gnome Maps and Firefox with Google Maps both displayed the right location down to the house, as can be seen in the screenshots. With the same LAN service and a Mac system there was no such luck with Apple Maps unless Location Services was turned off, though presumably Apple uses its own equivalent to MLS.

The Montgomery Ward Gasoline-Powered Clothes Iron

Before the advent of electricity in the home made electrically-heated clothes irons a possibility, ironing was a cumbersome process, with self-heated irons being an arguable improvement over solid (so-called sad) irons that required heating in an external heat source like a stove or fire. These self-heating irons used a variety of fuels, with the one featured on the [Our Own Devices] YouTube channel using gasoline for fuel, making it technically a gasoline-powered clothes iron.

The used gasoline form is LSR, which is commonly referred to as naphtha and is also sold as camping fuel today. In addition to the gasoline version a kerosene-powered version was also sold, so you had to better make sure you refueled your iron with the right fuel.

After pouring in fresh fuel you have to prime it by pushing the plunger a couple of times, before igniting the burner with a lit match via a hole in the side while opening the fuel valve. If you did things right, the iron will now be heating up. In a sense this makes it effectively like a camping stove, with also many of the same caveats, with such irons gaining a reputation for starting fires and causing bodily harm.

Due to decaying seals this iron in the video wasn’t fired up, but it was disassembled to show the internal components, along with a comparison of the kerosene version. Inside is a kind of crude carburetor that mixes air in with the fuel to get a combustible fuel-air mix, along with plenty of soot to attest to this iron having been regularly used.

Although electrical irons eventually removed all need for gasoline-powered irons, they were still used in mostly rural settings until the 1950s. Reading the Wikipedia entry on clothes irons makes one rather glad that these days we can iron our clothes without all the fuss and significant risk of accidents of these old irons.

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University Of Utah’s TRIGA Research Reactor Set To Produce Electricity

Research reactors come in many forms and sizes, with the TRIGA class being commonly found at universities. The TRIGA reactor at the University of Utah was installed in 1975, and for the past half century the thermal energy it produced was bled off into cooling systems. Now for a world’s first, the reactor will be used to generate electricity instead.

A TRIGA reactor core, with the blue glow from Cherenkov radiation. (Source: DoE, Wikimedia)
A TRIGA reactor core, with the blue glow from Cherenkov radiation. (Source: DoE, Wikimedia)

What makes the TRIGA design so practical for small research reactors is its inherent safety due to the use of uranium zirconium hydride (UZrH) fuel, which imposes a strong negative thermal coefficient on the reactivity. Along with no need for any kind of containment, these pool-type, water-cooled reactors thus allow for a pretty good look at the literal internals of the reactor core.

Their thermal power outputs range from 0.1 – 16 MWth, with the University of Utah reactor generating on the low end of the scale here, at 50 kWth. This energy will be partially used by a generator that has been developed by Elemental Nuclear, a startup company who looks to be trying to commercialize TRIGA fuel for microreactors with sodium coolant.

The installation at this TRIGA reactor should thus be seen as a proof-of-concept for Elemental Nuclear’s generator design, which uses a closed Brayton cycle with helium gas to generate an output of about 2-3 kWe from the ~13 kW generated by the turbine. This generated power will – of course – be used to power some racks with GPUs for ‘AI’ tasks. If successful, it could show the way for TRIGA-based microreactors to power datacenters.


Top image: the TRIGA reactor during a tour. (Credit: University of Utah)

Direct FDM Printing With Granules

The idea of FDM 3D printing using granules rather than filament is an appealing one: rather than having to wrangle spools of filament that need to adhere to strict dimensions and cannot be too flexible, you can instead just keep topping up a big hopper with fresh granules. This is what [HomoFaciens] has been tinkering with for a while now, with their Direct Granules Extruder V7.0 showing significant improvements.

There’s also an accompanying article, with details of previous granule extruder attempts detailed on the same site. Many of the improvements here focus on making sure the granules melt properly before they reach the end of the extruder, with the auger screw helping to push things along. While this seems straightforward, there are many details to get right, with the previous v6.2 version having issues like the hot plastic backing up into the cold section and clogging things up.

For the test bench a Prusa Mk4 FDM printer is used, with the standard extruder swapped for the experimental extruder. On the extruder the cold, top part is water cooled to ensure it stays cold, with each turn of the wood-screw-turned-auger providing the right extrusion speed. As can be seen with the print tests, the results look pretty good despite the extruder not having been tuned yet.

If you want to give it a shot yourself, the article page provides files for download.

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Why Opposed Piston Internal Combustion Engines Are Great

Converting the ignition of a fuel-air mixture into usable mechanical energy lies at the core of a dizzying number of internal combustion engines developed over the course of more than century. Although typical piston engines with a cylinder head and valve-train are the most common by far, and even rotary engines are quite well-known, the opposed-piston engine design is significantly more obscure. In a recent video by [driving 4 answers], this type of engine is covered and why it’s actually a pretty nifty ICE design with many benefits.

Achates opposed-piston design. (Source: driving 4 answers, YouTube)
Achates opposed-piston design. (Source: driving 4 answers, YouTube)

Above all, the design is mechanically far more simple, as it omits all the valves and timing-related hardware of the typical four-stroke ICE. Each ignition event pushes against two pistons at the same time, allowing for more of the kinetic energy to be converted into usable power, as well as enabling largely vibration-free operation in a more compact package, especially in the case of the Asender design that eliminates the second crankshaft of the Achates design. This makes the Asender rather similar to the 1914 Simpson’s design.

Despite these many advantages, opposed-piston engines have mostly led a quiet life in industrial and military applications, including tanks, submarines and airplanes. This is where the video also sees their continued use, but as a 2021 article in Autoweek suggests, we might be seeing more of these engines in everywhere from trucks to cars as well. Even if it’s only in hybrid cars where it would be in a generator role, there are many reasons why this ICE design would fit right into certain roles.

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Using Hamster Power To Charge A Phone

It seems fair to say that hamsters are a somewhat divisive pet, between their fluffiness, high-strung nature, short lifespan and incessant squeaking that sounds like some electronic device is trying to tell you something. With that in mind, maybe that having these fuzzy little critter take up some of the daily slack will help endear them to more people. Something like helping to charge mobile devices by converting their frantic exercise wheel time into electrical power. Cue [Flamethrower]’s hamster wheel-powered generator.

Due to the irregular pacing of the hamster on its wheel it makes sense to treat it as an energy harvesting problem, for which the common CJMCU-2557 module – featuring the TI BQ25770 – is a pretty good option. It covers a voltage input from 0.1 – 5.1 V after a cold start minimum of 0.6 V, with a maximum current of 0.1 A.

The modules come with a super capacitor to store collected energy, but you can further charge a connected battery, for which [Flamethrower] used salvaged 18650 Li-ion cells. After letting the hamster do its thing for a night in the – admittedly far too small wheel –  there’s enough power in the cell to at least start charging a smartphone, though sadly it’s not mentioned how much power was harvested.

Hopefully the hamster in question will be overclocked with a larger wheel, along with detailed measurements of how many hamsters it takes to charge the average phone.

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Defeating The [Works By Design]’s Unpickable Lock

Even though the very concept of an ‘unpickable lock’ is as plausible as making water not be wet, this doesn’t take away from the intellectual thrill of devising solutions to picking attacks and subsequently circumventing those solutions. Case in point the ‘unpickable’ traveling key lock that [Works by Design] recently featured and sent a few copies off to lock pickers such as [Lock Noob] who gave picking it a shake.

Many of the details and reasoning behind [Works by Design]’s lock design can be found in the original video, with [Lock Noob] going over the basic summary before getting to work trying to pick it.

Rather than trying to bump the tumbler lock mechanism or another indirect approach, the focus is here on an impressioning attack. Although in this traveling key mechanism the physical key is moved inside the lock, the pins of the tumbler lock will leave impressions on the brass blanks when the lock is gently forced to rotate, indicating that there’s still too much material there.

The approach here is thus to slowly file away these sections, with interestingly the plastic pin that [Works by Design] had added to dodge impressioning attacks not being too much of an issue. Thus after over an hour of turning-filing-turning-filing ad nauseam, the lock mechanism rotated, confirming that it had been defeated.

In the subsequent teardown of the lock it can be seen that a plastic pin is indeed rather fragile, with part of its top having been torn off. After replacing this damaged plastic pin with a fresh one, a foil-based impressioning attack is attempted by putting aluminium foil over a skeleton key, but this didn’t quite work out as the pins come in sideways and thus do not leave a useful impression.

Theoretically the pins would press down onto the soft foil, creating an almost immediate impression of the required key. Perhaps that leaving a solid side on the blank would make it work, but this is an approach that would have to be refined.

Either way, it shows that ‘unpickable’ depends on your definition, as ‘1+ hour of filing with knowledge of bitting depths’ would be considered ‘unpickable’ by some. At least it’s not as dramatic as a 2020 [Stuff Made Here] ‘unpickable lock’ hack that we covered, before it got shredded by the [LockPickingLawyer] with resulting list of potential fixes of multiple easy exploits before even having to resort to impressioning.

Considering that traveling key designs generally require at least a tedious impressioning attack, with potential ways to address this in a more substantial way, a redesign featuring these changes would be rather interesting to see picked. If it can defeat the average lockpicking enthusiast including those practicing the legal profession, it’s probably as close to ‘unpickable’ as can be before the bolt cutters and angle grinders are used against any vulnerable parts that aren’t the lock itself.

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