Mysterious Files PH

The fjords of Norway are world famous for their beauty, but even though the word itself is Norwegian, there are fjords all over the world in areas that used to be covered in glaciers. One of these areas is the Pacific Northwest of North America, we herit’s actually possible to travel by boat from the Seattle area all the way into Alaska without going to the Pacific Ocean, and although plenty of people make this journey by boat, [Matt] is planning on doing this journey on a jet ski with a custom camper on the back.

Normally a jet ski wouldn’t be the ideal platform for a multi-day on-boat adventure because of their size, but [Matt] found perhaps the largest jet ski ever made and he got a deal on it since it had previously been wrecked. Once he repaired the hull damage, he cut a sheet of plywood in half and put a hinge in the middle so it can unfold over the top of the jet ski but fold it away when he’s traveling. With the basic concept in place he took it right out on the water to a campsite before finalizing the construction of the rest of the tent, including the installation of a door, a window, and some interior lighting.

During that first night, a storm cropped up and pushed the craft out to shore while [Matt] was sleeping, so after realizing, waking up, and motoring back to shore, he made sure to tie the craft to a rock to avoid similar situations before going back to sleep. But besides some motion sickness which prevented him from cooking inside his camper, the rest of the adventure went off without a hitch. Before taking it on the Inside Passage he has been thinking of a few improvements like outriggers to keep it from rocking while he sleeps. [Matt] is no stranger to unusual camper builds, though, we recently featured his other camper which is an electric car converted to explore abandoned railroads.

While designing anything for operation in space has its challenges, there is at least one thing that is more of a problem for objects in Earth orbit than for deep-space probes: atomic oxygen. We like oxygen because we need it to live, but it is also highly reactive as a single atom. Luckily, on Earth, most of what we breathe is O₂. [Space Daily] talks about the challenges of the International Space Station dealing with the “space weather” of atomic oxygen in low Earth orbit.

Part of the problem is that even when we know better, we tend to think of the atmosphere coming to an abrupt end and space being a hard vacuum. But in reality, the atmosphere gradually dissipates, and at “only” 400 km above the Earth, the Space Station is really flying through a very thin atmosphere.

To compound the problem, this is above the ozone layer, so the Sun’s UV light rips O₂ into single oxygen atoms. Over time, these free oxygen atoms can affect many parts of a spacecraft exposed to them. Engineers first noticed that materials recovered from spacecraft had more damage and changes to material properties on the pieces facing the direction of travel. NASA has spent years testing different materials by mounting trays of different material samples outside the ISS.

Carbon-based polymers take a big hit from atomic oxygen exposure. Polymide film is frequently used, but it erodes with exposure. Carbon composites also lose mass. Other materials change in other ways. For example, an optical surface may roughen with exposure.

The usual answer is to over-design for mission objectives or to cover certain polymers with coatings like silicon dioxide or aluminum oxide, which are not as reactive to free oxygen. For a long-duration mission like the ISS, you may have to pay special attention to the materials in use. Very low satellites also need special care, as there is more oxygen in lower orbits.

There are other effects, too, such as extreme thermal cycles, debris strikes, and other indignities that space-traveling materials must withstand. But in deep space, atomic oxygen is a rare issue. Until, at least, we go somewhere else that has a lot of oxygen.

We don’t need to tell you: lasers are awesome. Those tiny red beams aren’t just for frustrating cats, but can do real work, be a source of infinite beauty, or constitute a science project in its own right — and you can win a $150 DigiKey gift certificate simply by writing your project up on Hackaday.io. The contest runs until July 23rd.

Of course, red lasers are only the beginning. If you have enough energy to move electrons into higher orbitals, you can make nearly anything lase. RGB setups can be breathtaking. Powerful IR and UV lasers are real tools. And the DIY side of lasering combines physics and electronics, with a spicy side of danger that needs to be contained.

We love laser builds of all sorts, and we’d like to see yours! Create a new Hackaday.io project that features what you’re working on, and we’ll pick our three favorites for a $150 gift certificate courtesy of this contest’s sponsor, DigiKey.

Honorable Mention Categories:

• Lightshow: A laser on its own makes a beam, but there’s so much more to a laser show than just a dot on the wall. If you’ve made your own projector, an RGB setup, or even something super simple with a spinning mirror, show it off here. We’re looking to see laser light beauty, and the machines that make it possible.

• DIY: This category is for the laser DIYers out there. If you made your own laser or laser support equipment, be it a TEA laser from scratch, or just a constant current driver to run a diode you salvaged from a projector, we want to see it. Have you resurrected an esoteric old device? Mixed up your own dyes? This category is all about the laser.

• With Remaining Eye: Lasers are not all fun and games; they can also do real work. If you’ve built a power laser project, or any functional device that relies on a laser to get the job done, it’s eligible here. Laser cutters, safety setups, data transfer over the light beam?  Any laser project that’s not about just looking good fits in here.

If you like to play with the coherent beams, head on over to Hackaday.io and detail your project — and don’t forget to enter it into the contest via the pulldown menu on the left side. If you win, you’ll have $150 to spend on more lasers. (We see you, with our remaining eye.)

It’s become a familiar theme over the last couple of decades — hardware is rendered useless when its manufacturer pulls the cloud service on which it depends. This is particularly annoying when the device is something which shouldn’t need a cloud service to run in the first place, and several manufacturers have found themselves in hot water because of this.

Somewhere in between is the Bose SoundTouch speaker system, which includes a set of six internet radio preset buttons. In early May the service behind them was shuttered, and now here’s [Tostmann] with an ESP32 firmware to bring them back.

As you might imagine, it’s a device that emulates just enough of the now-defunct Bose cloud service to keep the speaker happy, but it has a clever trick up its sleeve. Normally these hacks rely on DNS redirects at the router, but this one avoids that thanks to a diagnostic interface on the Bose unit that allows the rewriting of the server address. The ESP32 does this with its own address, and the speaker is none the wiser.

We like this hack, because of its ingenuity, and because it saves yet another orphaned cloud product from becoming e-waste. This isn’t the first time we’ve seen a manufacturer on the naughty step for these practices.

Header image: TAKA@P.P.R.S, CC BY-SA 2.0.

One simple screening tool for cognitive impairment is the clock-drawing test (CDT): the patient is provided with a printed circle and asked to draw a clock face with the hands pointing to a certain time. Depending on how the clock is drawn, this could indicate a variety of different disorders, particularly dementia, with a particular deformity in the drawing sometimes pointing to a specific issue. These failed tests inspired [John Silvia] to create a clock with a unique, disordered face.

The numerals in this clock face are placed exclusively along the right half of the clock (in the test, this can be a sign of damage to the right parietal lobe, or of executive dysfunction caused by dementia), and out of order. The hour hand is controlled by a servo motor, and the minute hand is mounted on a separate, commercially-purchased clock mechanism on the left-hand side of the face.

The frame for the clock and the face are 3D-printed, and the servo motor is controlled by an ESP32-C3 with an RTC module. To minimize power draw, a MOSFET disconnects the servo motor from power except for the once-per-hour position update. Once per month, the ESP32 connects to Wi-Fi to synchronize to NTP time, otherwise remaining in a low-power state – even its indicator LEDs are disconnected to save power. These efforts paid off: when the servo isn’t active, it draws only about 160 µA, and a set of three AA NiMH cells lasts about a year.

Since the servo motor draws most of the power budget, it wouldn’t make much difference, but the ESP32’s co-processor can also be used for ultra-low-power projects. For a happier take on a drawing-related clock, check out one of these projects.

It seems fair to say that Dyson sits at the intersection of impressive engineering and borderline ridiculous products. The Dyson Airblade 9KJ hand dryer that [ElectrArc240] recently took to bits would definitely seem to fall under the latter, combining an incredible amount of engineering all for the simple task of drying wet hands.

These hand dryers are rated for a cool 900 Watts, with an 0.5 W standby power consumption, though you can also switch it to a 650 W ‘eco mode’ when installing it. The air that gets sucked into the dryer first passes through a HEPA filter before it hits the heating element and then gets blown out of the handles onto one’s hands.

Both of these handles come with a presence sensor in the form of an ST VL53L3CX time-of-flight sensor, along with a path for the heated air towards the thin slits. Returning to the section just past the HEPA filter is the compressor, with a rather fancy airflow path that involves various stacked meshes. As can be seen in the video, where you’d expect basically a simple blower motor or so, there is a truly astounding amount of parts as the teardown progresses.

The motor disassembly is the first part where some desoldering and breaking of glue bonds is really necessary, but it gives full access to the driver board. The circuit used here is your typical IGBT-based gate driver, though with a mystery PIC MCU to do things. Following this the tear-down turns fully destructive, giving access to the motor internals.

Following an analysis of these internals we marvel at the carbon-fiber rotor that keeps the single magnet in one piece. This is another engineering choice that serves to justify the 1,000 quid price tag. All so that rest room visitors do not have to suffer the humility of using paper towels.

Although it can be hard to tell from looking at the often placid waters of the Earth’s oceans, their currents carry immense amounts of water around the globe on a daily basis, underlying a dynamic system that – much like the Earth’s atmosphere – plays a major role in everything from weather systems to local climates and ecosystems.

Of all these ocean currents the Atlantic meridional overturning circulation (AMOC) is perhaps the most famous, as it is basically the sole reason why Europe has the mild climate that it does today, courtesy of it carrying thermal energy from the equator all the way to the coast off Scandinavia.

Although collapsing an ocean current seems as improbable as stopping the jet streams in the upper atmosphere, it’s actually significantly easier due to how much ocean currents rely on factors that we can fairly easily influence. Over the past decades we have seen worrying signs that the AMOC is indeed weakening, with the million-dollar question being what scenario we’ll be looking at.

While collapsing the AMOC within a decade may be theoretically possible, current models seem to point towards a weakening by about half by the end of this century, with a recent research article by Valentin Portmann et al. in Science Advances going over the various statistical models to come to this conclusion.

The AMOC

Differences in temperature and salinity drive the ocean currents, causing the transport of water from one area to another as the system seeks to equalize itself. While this may bring to mind the atmosphere’s unrelenting jet streams, or the precarious and harrowing traversal of the area near the Cape of Good Hope where the Agulhas and Benguela currents meet, the AMOC is rather slow and ponderous, taking centuries to circulate.

Although it’s obviously a circular system, you can put its beginning at the point of energy input, which for the AMOC is the warm water of the Gulf of Mexico, from where the Gulf Stream flows through the Straits of Florida, following the coast line until it splits up into various smaller currents. The largest of these is the North Atlantic Current (NAC) that provides Europe with warmth and nutrients, while another significant branch is the Canary Current which brushes along the west coast of Africa as part of the North Atlantic Gyre.

As the warmer water travels along the surface of the ocean, it will gradually lose heat to the cooler air, especially once it reaches the North Atlantic. This thermohaline circulation (THC) follows the same pattern around the world’s oceans, with AMOC and the Southern Ocean overturning circulation (SOOC) forming its two main components, distributing heat and nutrients from the equatorial regions to the rest of the world’s oceans.

When the cooling water reaches the limits, the cooling water undergoes a density change that results in it sinking. This is caused by the process of brine rejection, which is the phenomenon where the freezing of saltwater rejects the salts from the forming ice matrix. This produces very salty brine, which is more dense than the surrounding ocean water, ergo it will sink and thereby terminate its branch of the THC.

Salinity Changes

An obvious conclusion one can draw from this brine rejection mechanism is that it can conceivably be interrupted, such as when enough freshwater slows down or disturbs the process. This collapse of the AMOC by freshwater forcing has been the topic of many studies over the years, with a 2024 article in Oceanography by René van Westen et al. investigating evidence that the AMOC is indeed on course for such an event.

At the core of this research are coupled models such as those of the Coupled Model Intercomparison Project (CMIP), which has been developed in phases since 1995. This a cooperative project in which researchers from around the world attempt to create the most complete climate model possible, in order to improve our understanding of the current climate and to make projections about what effects certain changes would have.

The Community Earth System Model (CESM)  is one of the contributing models to the CMIP5, using which Van Westen et al. tried to find evidence of a so-called tipping event in the AMOC. What’s notable about their study is that they didn’t attempt freshwater forcing using very large volumes of said freshwater, but still saw a gradual weakening over centuries.

With freshwater forcing consistently reducing the amount of salinity transferred via the NAC, this weakens the effect of brine rejection, thus weakening the AMOC until it eventually collapses. The balance here is the freshwater budget of the Atlantic Ocean, with rivers and melt-off from glaciers and such affecting said budget.

This is where we run into the conundrum that the analysis done by Portmann et al. on the CMIP6 predictions suggest a consistent weakening of the AMOC of about 50% by the year 2100, whereas Van Westen et al. observed a tipping point and rapid collapse of the AMOC to effectively zero using the CESM and a gradual freshwater forcing until said tipping point in the Atlantic freshwater budget is reached.

While a gradual weakening of the AMOC would obviously be bad, a full-blown collapse would obviously be significantly worse, potentially occurring over the span of a few decades and with any recovery deemed either unlikely or taking multiple millennia, as modelled by e.g. Curtis et al. in a 2024 study (free access PDF).

Implications

Whether the AMOC merely weakens by about half or collapses completely, the implications will be severe, with the same 2024 paper by Van Westen et al. providing a good overview, including a summary graphic:

Europe in particular would be hit, experiencing far colder seasons along with a sharp drop-off in precipitation. Yet other regions would not be left untouched either, with the Amazon region in particular experiencing a big shift in its climate patterns. In particular the periods when it’d experience cooler, wet weather and vice versa would be flipped, while even Africa and Australia would see a shift in precipitation levels.

In effect, there would likely be severe consequences for the ecosystems in South-America, while Europe would largely turn into a significantly more arid and colder region, similar to e.g. parts of Canada that are on the same latitude. With most of Canada’s population doing its utmost to avoid its more northern latitudes for rather reasonable reasons, it seems fair to say that a full-blown collapse of the AMOC would spell disaster for most European nations.

Keeping The AMOC Healthy

Now that we know the mechanism behind the AMOC and other parts of the THC, the solution to its weakening seems rather obvious: all we have to do is prevent excess freshwater forcing that risks diminishing the Atlantic Ocean’s freshwater budget and we should be golden. Doing so requires identifying the sources of this excess forcing, with a recent study by Oliver Mehling et al. making clear that where the freshwater forcing occurs matters a lot, with many models overestimating the time that we have left until an AMOC tipping point for this reason.

We can also look back on historical climate data courtesy of Antarctic ice cores that go back about a million years, though the Greenland ice cores are the golden standard for e.g. the Dansgaard-Oeschger event that occurred at the end of the last ice age. Since a warming climate naturally results in more freshwater forcing due to meltwater run-off into the oceans, we might be able to find some historical data that shows how the AMOC fared over the past millennia.

What we know is that the AMOC first formed about 34 million years ago when the continents shifted sufficiently to create the THC that we know today began to form. Since then the AMOC has apparently operated continuously, including the repeated glacial periods of the Pleistocene (2.58 million – 11,700 years ago) which ended around the time when the Dansgaard-Oeschger event occurred with an influx of freshwater into the Atlantic.

Of course, much of this historical data is reconstructed from proxies as part of paleoclimatology, so everything has to be taken with a grain of salt. Even so, we can for a large period directly measure aspects such as CO₂ concentration in the atmosphere before we have to resort to proxies. This shows us that to get similar atmospheric levels of that gas in Earth’s history we have to look all the way back to ~16 million years ago during the middle Miocene after atmospheric CO₂ levels had gradually come down from 1,600 ppm.

Even as some of us are contemplating direct weather modification, it might thus be an idea to consider the impact of anthropogenic greenhouse gases, as they clearly cause a very rapid increase in the global surface temperature. This warming then increases the melting of glaciers and similar, which in turn increases freshwater forcing into the THC, which thus could result in a sudden AMOC collapse.

Of course, the fun thing about such climate models is that they are only a projection based on our current knowledge. Only in hindsight will we know just how far off the mark we were, but when the stakes are this high, it might not be a terrible idea to err on the side of caution.

Featured image: Illustration of the Atlantic Meridional Overturning Circulation (AMOC).  Eric S. Taylor, Woods Hole Oceanographic Institution