Small Steam Generator Creates Educational Experience

October 27, 2024 by 13 Comments

Steam turbines have helped drive a large chunk of our technological development over the last century or so, and they’ll always make for interesting DIY. [Hyperspace Pirate] built a small turbine and boiler in his garage, turning fire into flowing electrons, and learning a bunch in the process.

[Hyperspace Pirate] based the turbine design on 3D printed Pelton-style turbines he had previously experimented with, but milled it from brass using a CNC router. A couple of holes had to be drilled in the side of the rotor to balance it. The shaft drives a brushless DC motor to convert the energy from the expanding steam into electricity.

To avoid the long heat times required for a conventional boiler, [Hyperspace Pirate] decided to use a flash boiler. This involves heating up high-pressure water in a thin coil of copper tube, causing the water to boil as it flows down the tube. To produce the high-pressure water feed the propane tank for the burner was also hooked up to the water tank to pressurize it, removing the need for a separate pump or compressed air source. This setup allows the turbine to start producing power within twelve seconds of lighting the burner — significantly faster than a conventional boiler.

Throughout the entire video [Hyperspace Pirate] shows his calculation for the design and tests, making for a very informative demonstration. By hooking up a variable load and Arduino to the rectified output of the motor, he was able to measure the output power and efficiency. It came out to less than 1% efficiency for turning propane into electricity, not accounting for the heat loss of the boiler. The wide gaps between the turbine and housing, as well as the lack of a converging/diverging nozzle on the input of the turbine are likely big contributing factors to the low efficiency.

Like many of his other projects, the goal was the challenge of the project, not practicality or efficiency. From a gyro-stabilized monorail, to copper ingots from algaecide and and a DIY cryocooler, he has sure done some interesting ones.

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How Pollution Controls For Cargo Ships Made Global Warming Worse

October 27, 2024 by 39 Comments

In 2020 international shipping saw itself faced with new fuel regulations for cargo ships pertaining to low sulfur fuels (IMO2020). This reduced the emission of sulfur dioxide aerosols from these ships across the globe by about 80% practically overnight and resulting in perhaps the biggest unintentional geoengineering event since last century.

As detailed in a recent paper by [Tianle Yuan] et al. as published in Nature, by removing these aerosols from the Earth’s atmosphere, it also removed their cooling effect. Effectively this change seems to have both demonstrated the effect of solar engineering, as well as sped up the greenhouse effect through radiative forcing of around 0.2 Watt/m2 of the global ocean.

The inadvertent effect of the pollution by these cargo ships appears to have been what is called marine cloud brightening (MCB), with the increased reflectivity of said clouds diminishing rapidly as these pollution controls came into effect. This was studied by the researchers using a combination of satellite observations and a chemical transport model, with the North Atlantic, the Caribbeans and South China Sea as the busiest shipping channels primarily affected.

Although the lesson one could draw from this is that we should put more ships on the oceans burning high-sulfur fuels, perhaps the better lesson is that MCB is a viable method to counteract global warming, assuming we can find a method to achieve it that doesn’t also increase acid rain and similar negative effects from pollution.

Featured image: Time series of global temperature anomaly since 1980. (Credit: Tianle Yuan et al., Nature Communications Earth Environment, 2024)

Clockwork Rover For Venus

October 26, 2024 by 28 Comments

Venus hasn’t received nearly the same attention from space programs as Mars, largely due to its exceedingly hostile environment. Most electronics wouldn’t survive the 462 °C heat, never mind the intense atmospheric pressure and sulfuric acid clouds. With this in mind, NASA has been experimenting with the concept of a completely mechanical rover. The [Beardy Penguin] and a team of fellow students from the University of Southampton decided to try their hand at the concept—video after the break.

The project was divided into four subsystems: obstacle detection, mechanical computer, locomotion (tracks), and the drivetrain. The obstacle detection system consists of three (left, center, right) triple-rollers in front of the rover, which trigger inputs on the mechanical computer when it encounters an obstacle over a certain size. The inputs indicate the position of each roller (up/down) and the combination of inputs determines the appropriate maneuver to clear the obstacle. [Beardy Penguin] used Simulink to design the logic circuit, consisting of AND, OR, and NOT gates. The resulting 5-layer mechanical computer quickly ran into the limits of tolerances and friction, and the team eventually had trouble getting their design to work with the available input forces.

Due to the high-pressure atmosphere, an on-board wind turbine has long been proposed as a viable power source for a Venus rover. It wasn’t part of this project, so it was replaced with a comparable 40 W electric motor. The output from a logic circuit goes through a timing mechanism and into a planetary gearbox system. It changes output rotation direction by driving the planet gear carrier with the sun gear or locking it in a stationary position.

As with many undergraduate engineering projects, the physical results were mixed, but the educational value was immense. They got individual subsystems working, but not the fully integrated prototype. Even so, they received several awards for their project and even came third in an international Simulink challenge. It also allowed another team to continue their work and refine the subsystems. Continue reading “Clockwork Rover For Venus” →

Geochron world time clock

Geochron: Another Time, Another Timeless Tale

October 26, 2024 by 10 Comments

The Geochron World Time Indicator is a clock that doubles as a live map of where the sun is shining on the Earth. Back in its day, it was a cult piece that some have dubbed the “Rolex on the wall.” Wired’s recent coverage of the clock reminded us of just how cool it is on the inside. And to dig in, we like [Attoparsec]’s restoration project on his own mid-1980s Geochron, lovingly fixing up a clock he picked up online.

[Attoparsec]’s recent restoration shares insights into the clock’s fascinating mechanics. Using a synchronous motor, transparent slides, and a lighted platen, the Geochron works like a glorified slide projector, displaying the analemma—a figure-eight pattern that tracks the sun’s position over the year.

But if you’re looking for a digital version, way back in 2011 we showcased [Justin]’s LED hack of FlorinC’s “Wise Clock”, which ingeniously emulated the Geochron’s day-night pattern using RGB LEDs, swapping out the faceplate for a world map printed on vellum. That’s probably a much more reasonable way to go these days. Why haven’t we seen more remakes of these?

The Glacial IPv6 Transition: Raising Questions On Necessity And NAT-Based Solutions

October 26, 2024 by 72 Comments

A joke in networking circles is that the switch from IPv4 to IPv6 is always a few years away. Although IPv6 was introduced in the early 90s as a result of the feared imminent IPv4 address drought courtesy of the blossoming Internet. Many decades later, [Geoff Huston] in an article on the APNIC blog looks back on these years to try to understand why IPv4 is still a crucial foundation of the modern Internet while IPv6 has barely escaped the need to (futilely) try to tunnel via an IPv4-centric Internet. According to a straight extrapolation by [Geoff], it would take approximately two more decades for IPv6 to truly take over from its predecessor.

Although these days a significant part of the Internet is reachable via IPv6 and IPv6 support comes standard in any modern mainstream operating system, for some reason the ‘IPv4 address pool exhaustion’ apocalypse hasn’t happened (yet). Perhaps ironically, this might as [Geoff] postulates be a consequence of a lack of planning and pushing of IPv6 in the 1990s, with the rise of mobile devices and their use of non-packet-based 3G throwing a massive spanner in the works. These days we are using a contrived combination of TLS Server Name Indication (SNI), DNS and Network Address Translation (NAT) to provide layers upon layers of routing on top of IPv4 within a content-centric Internet (as with e.g. content distribution networks, or CDNs).

While the average person’s Internet connection is likely to have both an IPv4 and IPv6 address assigned to it, there’s a good chance that only the latter is a true Internet IP, while the former is just the address behind the ISP’s CG-NAT (carrier-grade NAT), breaking a significant part of (peer to peer) software and services that relied on being able to traverse an IPv4 Internet via perhaps a firewall forwarding rule. This has now in a way left both the IPv4 and IPv6 sides of the Internet broken in their own special way compared to how they were envisioned to function.

Much of this seems to be due to the changes since the 1990s in how the Internet got used, with IP-based addressing of less importance, while giants like Cloudflare, AWS, etc. have now largely become ‘the Internet’. If this is the path that we’ll stay on, then IPv6 truly may never take over from IPv4, as we will transition to something entirely else. Whether this will be something akin to the pre-WWW ‘internet’ of CompuServe and kin, or something else will be an exciting revelation over the coming years and decades.

Header: Robert.Harker [CC BY-SA 3.0].

Sad clown holding melted ice cream cone

McDonalds Ice Cream Machines Gain A DMCA Exemption

October 26, 2024 by 71 Comments

An unlikely theatre for an act in the right-to-repair saga came last year in the form of McDonalds restaurants, whose McFlurry ice cream machines are prone to breakdown. The manufacturer had locked them down, and a franchisee with a broken machine had no option but to call them for an expensive repair job. iFixit and Public Knowledge challenged this with a request for a DMCA exemption from the Copyright Office, and now news emerges that this has been granted.

The exemption in question isn’t specific to McDonalds, instead it applies to retail food preparation equipment in general, which includes ice-cream machines. We’re guessing that franchisees won’t be breaking out the screwdrivers either, instead it’s likely to lower significantly the cost of a service contract for them and any other food industry operators hit with the same problem. Meanwhile any hackers who’ve picked up an old machine can now fix it themselves without breaking the law, and maybe the chances of your local Mickey D’s having no McFlurries have gone down.

This story has featured more than once on these pages, so catch up here, and here.

A New Chinese Radio Breaks Cover, Is It Worth It?

October 26, 2024 by 25 Comments

Scanning the firehose of new electronic kits and modules coming from the usual Chinese suppliers can be a rewarding experience, as sometimes among the endless breakout boards comes an item that looks interesting enough to try. As an example there’s a receiver kit being given a quick review by [Tech Minds], offering AM and HF multi-mode, FM broadcast, and air band alongside what appear to be digital streaming features.

Looking at it, though all the RF part is hidden under screening cans we’re guessing it might contain one of the Silicon Labs all-in-one receiver chips, but the whole appears to deliver a useful receiver with a comprehensive interface. The review isn’t quite technical enough so we can’t glean a lot more, but it looks as though it could be useful. We’d be tempted to snag one for review, but since with very few exceptions we pay for the stuff we review, it’s a mite expensive at $50+ for yet another radio.

There’s an ongoing question with all these cheap kits and modules though, first of all where did the design come from and are we freeloading on someone else’s hard work, but then whether or not what you’re getting is a knock-off using defective semiconductors or with bean-counting parts removal degrading performance. We’re guessing more will come out about this radio in due course, and we can all make our own judgement. Meanwhile this one can be found on AliExpress or Banggood, so take a look and see if you’re tempted.

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