Mysterious Files PH

Even if the world has already settled on plain old propellers as the way to make quadcopter drones fly, this doesn’t mean that you cannot give other designs a shake to see what kind of flying performance they result in. For example impeller designs that depart radically from standard propellers – themselves a sub-category of axial impellers – and go radically radial instead as in this design by [quadmovr] with accompanying demonstration video.

This is itself a remix of a design by [Baba] to make it fit the target 1750KV T-mount motor. As for whether this is a design that you want to slap on your own quadcopter, the obvious disadvantage is that it’s much heavier than regular propellers.

Weighing [quadmovr]’s drone without battery pack and with these 3D-printed PETG impellers shows them to weigh 189 grams. This compares to 141 grams with the standard three-bladed propellers, or a hefty 12.8 gram weight penalty per impeller. Naturally this translates into less flying time, so what are the advantages?

The noise profile of the impeller design is definitely more pleasant, and much like novice quadcopters with the protective ring around the propellers these impellers should be more robust. On the other hand increased mass adds to inertia, and there is a lot more surface area with the air to add drag, so despite the absolutely sick moves that [quadmovr] pulls off with both impeller configurations in the video one has to admit that regular three-blade propellers do have the edge here.

In the US, among other places, housing costs are skyrocketing. It can sometimes be difficult to get a feel for the scale of the issue and how it hits neighborhoods differently. [Justin Blinder] has designed a device to help people get a more visceral understanding of the problem.

In New York City, Citi Bikes are everywhere in the city’s transportation landscape. [Blinder] used a GPS module plugged into an ESP32S3 to vary the amount of resistance on one of these bikes by actuating the front brake with a servo. As a rider takes the bike through different neighborhoods, the resistance varies in proportion to the rent burden experienced there.

[Blinder] explains, “One of the main technical challenges was calibrating this relationship so that the changes were physically noticeable without feeling abrupt or unsafe.” As rent burden is merely the percentage of income taken up by rent in an area (by the block in this dataset), it is only one indicator of the additional friction a family might feel in an area, but a useful one to at least begin to convey the disparities in the urban environment. We really like how this connects abstract statistics to something more experiential.

If you’re looking for some other bike hacks, how about wireless brakes or a sleeper e-bike with a solenoid display?

via Next City

Nuclear power really hit its stride in the 1950s. In the post-war period, there was a rush to develop peaceful uses for splitting the atom, beyond its application as a weapon of war. Soon enough, nuclear reactors were hooking up to power grids and helping propel ships and submarines around the globe.

Eventually, this led to an obvious idea—what if a ship with a reactor could serve as a floating nuclear power station? That question would be answered in the mid-1960s, with an American project of some strategic importance.

Whatever Floats Your Boat

You might think that the first floating nuclear power plant would have been a US or Soviet navy project, but you’d be quite wrong. Instead, it was actually the US Army which was responsible for achieving this feat. The project began as part of the US Army Nuclear Power Program, which was intended to develop small reactors that could be deployed to remote regions to supply electricity. One of the results of that program was MH-1A, the nuclear reactor abord the vessel otherwise known as the USS Sturgis.

The contract for the Sturgis’ reactor was awarded to Martin Marietta in 1961. Termed the MH-1A, standing for Mobile, High Power, the reactor was a pressurized water unit running on low-enriched uranium, built inside a 350-ton containment vessel. Nameplate capacity was a healthy 10 megawatts. The ship itself was not a clean-sheet design; instead, it was built out of a converted Liberty Ship left over from World War II. The former cargo vessel was formerly known as the SS Charles H. Cugle. As part of its conversion, it had its propulsion system removed, since it was intended to operate from fixed moorings or anchorage for extended periods of time. It was deemed uneconomical to otherwise maintain the capacity for independent propulsion.

The MH-1A reactor was installed in the Sturgis while it was moored at Gunston Cove, near the Fort Belvoir facility that hosted the Army’s very first nuclear reactor, the SM-1. The reactor first went critical in January 1967, and was accepted into Army service six months later in July. The Sturgis would remain at Gunston Cove for the following 11 months, where it supplied electricity to Fort Belvoir in lieu of any required operational use.

The Sturgis did not have to wait long to be called into service. It was initially considered for deployment in the Vietnam theatre, but instead, it would wind up serving in Central America—but not for entirely unrelated reasons. In 1968, the Panama Canal was

facing somewhat of a crisis. The dry season led to water shortages, with authorities forced to ration what was ran through the Gatun Hydroelectric Station for local energy needs, and what was used to run the locks to allow ships to transit the Panama Canal. To aid in keeping the canal open, the US Army deployed both the Sturgis, as well as the Andrew J. Weber, a diesel-powered power barge of some 20 MW capacity. The two ships were hooked up to support the power needs of the Canal Zone, in turn freeing up water resources for the locks of the Panama Canal. This allowed the passage of an additional 15 ships through the canal per day. The deployment wasn’t entirely altruistic, of course. Keeping traffic flowing through the canal was undoubtedly an aid to US logistics during the Vietnam War, with much materiel passing through this route during the conflict. The Sturgis ultimately stayed on station until 1975, eventually being replaced by Hitachi turbine generators instead.

Beyond its trip to Panama, the Sturgis didn’t have much else to do. It was retired from service in 1976, since the Army Reactor Program had been ended and its generation capacity had been replaced with more practical solutions at the canal. It returned to the US in 1977, where its fuel was removed at Fort Belvoir. It was then moored as part of the James River Reserve Fleet for long-term storage. Eventually, a $35 million contract was awarded in 2014 to decommission and dispose of the reactor, with the rest of the ship then to be scrapped as per usual shipbreaking practices. The process was completed by 2019, and the world’s first floating nuclear power station was no more.

The story of the Sturgis is rather a strange one. Military planners conceived that a floating nuclear power plant could be incredibly useful, and not long after it was completed, they found the perfect application for it. Once that application was no longer important, the ship was mothballed in short order.

Since then, the world hasn’t seen a whole lot of floating nuclear power stations. Russian efforts netted a single nuclear-powered barge in 2019, but plans to produce more have not yet come to fruition. Ultimately, it seems hard enough for our modern civilization to put together new reactors for use on land, let alone portable floating units that can be deployed at will. It seems like there just isn’t quite enough demand to justify their existence in greater numbers than one at a time.

Featured image: “MH-1A, STURGIS Nuclear Barge”, US Army Corps of Engineers

Coaxing a DVI signal out of a microcontroller to drive a DVI or HDMI screen has been possible for a while now, but limitations in what the devices can do has, in turn, placed a limit on the resolution that can be delivered. Now [Aaron Gayle] has broken through a barrier by generating 1080p video from an RP2350. The previous best from Raspberry Pi Pico-class microcontrollers was 720p, which an RP2040 could deliver. The 2350 is faster and has faster peripherals, but even then, to reach this resolution he had to overclock it to 372 MHz. For all the impressive achievement, there’s still a limitation. Lacking space for a framebuffer, he generates scanline by scanline, a technique we associate more with 8-bit computers from the 1980s.

The 1080p video code is part of a package called TVtop, a board game in which the game board is displayed on the TV and whose players interact from their phones via Wi-Fi. For that reason, there’s an ESP32 in the project too, though it has nothing to do with the video hack.

Now that an RP2350 has been shown to generate 1080p, we look forward to seeing others building upon this achievement in terms of what video can be delivered. If you do something, be sure to let us know.

Meanwhile, Aaron tells us he was inspired by this Hackaday story, which asked if it was possible.

Header image: Raspberry Pi, CC BY-SA 4.0.

Some sad news to start this week off — after 52 years in business, Sherline has announced they are winding down their manufacturing operations. By the end of October they estimate they’ll have produced their last tool, and although they will no longer be making new products, they plan on supporting their existing customers for as long as possible. Although from the sound of the press release, that may mean simply keeping the website up and selling through their inventory of spare parts.

The company offered a range of American-made miniature lathes and mills, and while their manual machines may have been better known in our community, they did eventually branch out into CNC. The press release doesn’t go into a lot of details the chain of events that lead up to this decision, but they do mention the challenges of modern manufacturing and the lingering after effects of the COVID pandemic.

At first blush it might seem strange that the company would falter just as desktop CNCs appear to finally be gaining momentum, but of course that doesn’t change their ability to compete with overseas manufacturing in terms of price.

Of course, keeping competitive is only a concern when you actually have competitors in the first place. That’s the situation that NASA and Boeing may find themselves in should SpaceX decide to retire the Crew Dragon after 2030. While the International Space Station will (probably) be out of the equation by that point, the US space agency will still need the capability to fly humans to…somewhere, and that means there will be lucrative government contracts up for grabs.

The chances of any other American company developing and launching a human-rated spacecraft between now and the end of the decade is pretty much zero, which means Boeing will have to pick up the slack with their Starliner capsule. Or at least, try to, as Starliner hasn’t exactly had the best track record so far. Although by the 2030s SpaceX plans to have transitioned most if not all of their operations to Starship, one does wonder if a big enough check from Uncle Sam could change their minds.

While the market for putting humans into orbit might be shrinking, there’s no shortage of new ways to move stuff around here on terra firma. IEEE Spectrum has the details on a rather unique electric vehicle from startup Revoy that’s designed to sit between a traditional diesel semitruck and its cargo trailer. This essentially turns the combined rig into a hybrid, with the EV module capable of pushing the load for up to 400 kilometers (250 miles). Though it might seem rather low-tech, this approach offers a major advantage in that fleets won’t need to replace their existing vehicles to take advantage of the efficiency gains promised by electrification — with the company claiming that it can cut a truck’s total fuel consumption by up to 85%.

If the day has been going a little too smoothly for your liking and you need something to be frustrated about, here’s something to agonize over. Reality Check shows you images and tasks you with determining if they’re AI-generated or not. As the timer ticks down you’ll be furiously searching the background for malformed bits of text or extra fingers, but even that trick won’t necessarily save you in this era of increasingly capable image models.

Finally, while AI is getting very good at fooling grandmothers on Facebook, we can take some comfort in the knowledge that it’s finding the business world far more difficult to dominate. Drew Magary recently wrote up the experience of visiting a store “managed” by an AI model for SFGATE, and it sounds like things are going just as poorly as you’d imagine.

Given agency to pick the items it wanted to sell in the store the computer stocked the shelves with bric-a-brac that has no obvious overarching theme, and although there’s a human staffer behind the counter, purchases apparently need to be negotiated with the AI via voice chat. The store is burning through its initial investment money with no profit in sight, made all the worse by the fact that one of the line items on the budget is the token cost to run the AI that’s mismanaging the whole thing in the first place.

It’s an entertaining read, and a refreshing splash of cold water on the general AI hype that seems so prevalent these days. But its impact as a condemnation of machine learning in business is undermined a bit when the bottom of every page on SFGATE reminds readers that they are producing content with the assistance of generative AI. C’est la vie.

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.

TEMPEST attacks are often the most effective way to break air-gapped security: rather than directly accessing a computer, the attacker records the system’s unintended radio emissions and uses them to reconstruct its internal operations. This kind of attack was much more effective in the days of noisy, high-voltage CRT displays, and has gradually become less effective as electronics migrate to quieter, less powerful components. A group of researchers, however, has found that even modern electronics can become effective TEMPEST transmitters when irradiated with an RF signal.

The RF a device emits depends on the unintentional antennas in its internal structure. These are difficult to eliminate, and it’s usually not worth the effort; they’re usually small enough that they only effectively radiate at much higher frequencies than the electronics carry. The researchers’ technique, called InjectEave, radiated these electronics with a radio frequency tuned to their internal antennas, injecting that frequency into the circuit. Nonlinear electronic components, such as amplifiers, then mix the injected frequency with the internal signal, creating RF sidebands. This mixed signal then radiates out of the device and can be picked up and demodulated to recover the device’s internal signal.

In principle, almost any semiconductor device will perform mixing to some extent; in testing, the researchers had success with an amplifier, analog-to-digital converter, power converter, and switching MOSFETs, but detected no significant emissions without an injected signal. For a portable setup, the researchers used a USRP B210 SDR for transmission and a spectrum analyzer to demodulate the received signal.

This was able to recover audio from wired headphones, wireless headphones, and a wireless landline, and detect the state of a smart lamp and a smart fan. All of this worked over short distances, even through walls, and with a power amplifier, the range increased to 30 meters. Even with multiple devices present, they could focus on one by tuning the injection frequency to resonate with its internal antennas. Perhaps most impressive (or concerning) was a demonstration with the VoIP phone: the researchers were able to listen in on the person speaking, clone that person’s voice, synthesize new speech in that voice, and remotely inject it onto the phone call, altering the call in real time.

If the history of these attacks is any guide, it won’t be too long before we see an open-source implementation of this technique; we’ve already seen a few approaches to traditional TEMPEST. This kind of unintended nonlinear mixing can also be used to find bugs or electronics.

Getting rid of rodents like squirrels, mice, or groundhogs is a lot like digging a hole on the beach. No matter how much you remove, it’ll always fill back in. So, while [Super Valid Designs] could keep trapping and “removing” the mice in his chicken coop, more will always work their way back in. His theory is that removing them live from the chicken coop and placing them some distance away will be more effective, and with this semi-automated ski lift that traps them and carts them off, it might end up being less work too.

The build comes to us in roughly two parts. The first is the gondolas, which not only cart the mice down the hill to freedom but also double as the mousetrap themselves. They are placed in the chicken coop, and a trap door on the ceiling with bait causes the mice to fall inside. 3D printed with acrylic windows, they are a luxurious way for a mouse to travel. At the bottom, another trap door opens onto a pile of brush, releasing the mice. The second part is the lift, built hastily out of wood and other parts lying around. After much hiking up and down the hill, [Super Valid Designs] eventually got it working properly and reliably toting the mice and automatically releasing them at the bottom of the hill.

It’s a bit too early to tell if this method is more effective than more traditional methods of dealing with mice. But it was at least a fun way to deal with the problem while he also works on more effective methods of preventing the mice from getting into his buildings in the first place. There are some simpler catch-and-release mousetraps out there as well if a ski lift is out of the question for whatever reason.