If we asked you to think of a device that converts a chemical reaction into electricity, you’d probably say we were thinking of a battery. That’s true, but there is another device that does this that is both very similar and very different from a battery: the fuel cell.

In a very simple way, you can think of a fuel cell as a battery that consumes the chemicals it uses and allows you to replace those chemicals so that, as long as you have fuel, you can have electricity. However, the truth is a little more complicated than that. Batteries are energy storage devices. They run out when the energy stored in the chemicals runs out. In fact, many batteries can take electricity and reverse the chemical reaction, in effect recharging them. Fuel cells react chemicals to produce electricity. No fuel, no electricity.

Superficially, the two devices seem very similar. Like batteries, fuel cells have an anode and a cathode. They also have an electrolyte, but its purpose isn’t the same as in a conventional battery. Typically, a catalyst causes fuel to oxidize, creating positively charged ions and electrons. These ions move from the anode to the cathode, and the electrons move from the anode, through an external circuit, and then to the cathode, so electric current occurs. As a byproduct, many fuel cells produce potentially useful byproducts like water. NASA has the animation below that shows how one type of cell works.

History

Sir William Grove seems to have made the first fuel cell in 1838, publishing in The London and Edinburgh Philosophical Magazine and Journal of Science. His fuel cell used dilute acid, copper sulphate, along with sheet metal and porcelain. Today, the phosphoric acid fuel cell is similar to Grove’s design.

The Bacon fuel cell is due to Francis Thomas Bacon and uses alkaline fuel. Modern versions of this are in use today by NASA and others. Although Bacon’s fuel cell could produce 5 kW, it was General Electric in 1955 that started creating larger units. GE chemists developed an ion exchange membrane that included a platinum catalyst. Named after the developers, the “Grubb-Niedrach” fuel cell flew in Gemini space capsules. By 1959, a fuel cell tractor prototype was running, as well as a welding machine powered by a Bacon cell.

One of the reasons spacecraft often use fuel cells is that many cells take hydrogen and oxygen as fuel and put out electricity and water. There are already gas tanks available, and you can always use water.

Types of Fuel Cells

Not all fuel cells use the same fuel or produce the same byproducts. At the anode, a catalyst ionizes the fuel, which produces a positive ion and a free electron. The electrolyte, often a membrane, can pass ions, but not the electrons. That way, the ions move towards the cathode, but the electrons have to find another way — through the load — to get to the cathode. When they meet again, a reaction with more fuel and a catalyst produces the byproduct: hydrogen and oxygen form water.

Most common cells use hydrogen and oxygen with an anode catalyst of platinum and a cathode catalyst of nickel. The voltage output per cell is often less than a volt. However, some fuel cells use hydrocarbons. Diesel, methanol, and other hydrocarbons can produce electricity and carbon dioxide as a byproduct, along with water. You can even use some unusual organic inputs, although to be fair, those are microbial fuel cells.

Common types include:

• Alkaline – The Bacon cell was a fixture in space capsules, using carbon electrodes, a catalyst, and a hydroxide electrolyte.
• Solid acid – These use a solid acid material as electrolyte. The material is heated to increase conductivity.
• Phosphoric acid – Another acid-based technology that operates at hotter temperatures.
• Molten carbonate – These work at high temperatures using lithium potassium carbonate as an electrolyte.
• Solid oxide – Another high temperature that uses zirconia ceramic as the electrolyte.

In addition to technology, you can consider some fuel cells as stationary — typically producing a lot of power for consumption by some power grid — or mobile.

Using fuel cells in stationary applications is attractive partly because they have no moving parts. However, you need a way to fuel it and — if you want efficiency — you need a way to harness the waste heat produced. It is possible, for example, to use solar power to turn water into gas and then use that gas to feed a fuel cell. It is possible to use the heat directly or to convert it to electricity in a more conventional way.

Space

Fuel cells have a long history in space. You can see how alkaline Bacon cells were used in early fuel cells in the video below.

Very early fuel cells — starting with Gemini in 1962 — used a proton exchange membrane. However, in 1967, NASA started using Nafion from DuPont, which was improved over the old membranes.

However, alkaline cells had vastly improved power density, and from Apollo on, these cells, using a potassium hydroxide electrolyte, were standard issue.

Even the Shuttle had fuel cells. Russian spacecraft also had fuel cells, starting with a liquid oxygen-hydrogen cell used on the Soviet Lunar Orbital Spacecraft (LOK).

The shuttle’s power plant measured 14 x 15 x 45 inches and weighed 260 pounds. They were installed under the payload bay, just aft of the crew compartment. They drew cryogenic gases from nearby tanks and could provide 12 kW continuously, and up to 16 kW. However, they typically were taxed at about 50% capacity. Each orbiter’s power plant contained 96 individual cells connected to achieve a 28-volt output.

Going Mobile

There have been attempts to make fuel cell cars, but with the difficulty of delivering, storing, and transporting hydrogen, there has been resistance. The Toyota Mirai, for example, costs $57,000, yet owners sued because they couldn’t obtain hydrogen. Some buses use fuel cells, and a small number of trains (including the one mentioned in the video below).

Surprisingly, there is a market for forklifts using fuel cells. The clean output makes them ideal for indoor operation. Batteries? They take longer to charge and don’t work well in the cold. Fuel cells don’t mind the cold, and you can top them off in three minutes.

There have been attempts to put fuel cells into any vehicle you can imagine. Airplanes, motorcycles, and boats sporting fuel cells have all made the rounds.

Can You DIY?

We have seen a few fuel cell projects, but they all seem to vanish over time. In theory, it shouldn’t be that hard, unless you demand commercial efficiency. However, it can be done, as you can see in the video below. If you make a fuel cell, be sure to send us a tip so we can spread the word.

Featured image: “SEM micrograph of an MEA cross section” by [Xi Yin]

Plenty of consumer goods, from passenger vehicles to toys to electronics, get tossed out prematurely for all kinds of reasons. Repairable damage, market trends, planned obsolescence, and bad design can all lead to an early sunset on something that might still have some useful life in it. This was certainly the case for a sound system that [Bill] found — despite a set of good speakers, the poor design of the hardware combined with some damage was enough for the owner to toss it. But [Bill] took up the challenge to get it back in working order again.

The main problem with this unit is that of design. It relies on a remote control to turn it on and operate everything, and if that breaks or is lost, the entire unit won’t even power on. Tracing the remote back to the control board reveals a 15-pin connector, and some other audio sleuths online have a few ways of using this port to control the system without the remote.

[Bill] found a few mistakes that needed to be corrected, and was eventually able to get an ESP8266 (and eventually an ESP32) to control the unit thanks largely to the fact that it communicates using a slightly modified I2C protocol.

There were a few pieces of physical damage to correct, too. First, the AC power cable had been cut off which was simple enough to replace, but [Bill] also found that a power connector inside the unit was loose as well. With that taken care of he has a perfectly functional and remarkably inexpensive sound system ready for movies or music. There are some other options available for getting a set of speakers blasting tunes again as well, like building the amplifier for them from scratch from the get-go.

DIY mechatronics always has some unique challenges when relying on simple tools. 3D printing enables some great abilities but high precision gearboxes are still a difficult problem for many. Answering this problem, [Sergei Mishin] has developed a very interesting gearbox solution based on a research paper looking into simple rollers instead of traditional gears. The unique attributes of the design come from the ability to have a compact angled gearbox similar to a bevel gearbox.

Multiple rollers rest on a simple shaft allowing each roller to have independent rotation. This is important because having a circular crown gear for angled transmission creates different rotation speeds. In [Sergei]’s testing, he found that his example gearbox could withstand 9 Nm with the actual adapter breaking before the gearbox showing decent strength.

Of course, how does this differ from a normal bevel gear setup or other 3D printed gearboxes? While 3D printed gears have great flexibility in their simplicity to make, having plastic on plastic is generally very difficult to get precise and long lasting. [Sergei]’s design allows for a highly complex crown gear to take advantage of 3D printing while allowing for simple rollers for improved strength and precision.

While claims of “zero backlash” may be a bit far-fetched, this design still shows great potential in helping make some cool projects. Unique gearboxes are somewhat common here at Hackaday such as this wobbly pericyclic gearbox, but they almost always have a fun spin!

Thanks to [M] for the tip!

Although there are some ferries and commercial boats that use a multi-hull design, the most recognizable catamarans by far are those used for sailing. They have a number of advantages over monohull boats including higher stability, shallower draft, more deck space, and often less drag. Of course, these advantages aren’t exclusive to sailboats, and plenty of motorized recreational craft are starting to take advantage of this style as well. It’s also fairly straightforward to remove the sails and add powered locomotion as well, as this electric catamaran demonstrates.

Not only is this catamaran electric, but it’s solar powered as well. With the mast removed, the solar panels can be fitted to a canopy which provides 600 watts of power as well as shade to both passengers. The solar panels charge two 12V 100ah LifePo4 batteries and run a pair of motors. That’s another benefit of using a sailing cat as an electric boat platform: the rudders can be removed and a pair of motors installed without any additional drilling in the hulls, and the boat can be steered with differential thrust, although this boat also makes allowances for pointing the motors in different directions as well. 

In addition to a highly polished electric drivetrain, the former sailboat adds some creature comforts as well, replacing the trampoline with a pair of seats and adding an electric hoist to raise and lower the canopy. As energy density goes up and costs come down for solar panels, more and more watercraft are taking advantage of this style of propulsion as well. In the past we’ve seen solar kayaks, solar houseboats, and custom-built catamarans (instead of conversions) as well.

Continuing the scientific theme of adding fluorescent proteins to everything that moves, this time spiders found themselves at the pointy end of the CRISPR-Cas9 injection needle. In a study by researchers at the University of Bayreuth, common house spiders (Parasteatoda tepidariorum) had a gene inserted for a red fluorescent protein in addition to having an existing gene for eye development disabled. This was the first time that spiders have been subjected to this kind of gene-editing study, mostly due to how fiddly they are to handle as well as their genome duplication characteristics.

In the research paper in Angewandte Chemie the methods and results are detailed, with the knock-out approach of the sine oculis (C1) gene being tried first as a proof of concept. The CRISPR solution was injected into the ovaries of female spiders, whose offspring then carried the mutation. With clear deficiencies in eye development observable in this offspring, the researchers moved on to adding the red fluorescent protein gene with another CRISPR solution, which targets the major ampullate gland where the silk is produced.

Ultimately, this research serves to demonstrate that it is possible to not only study spiders in more depth these days using tools like CRISPR-Cas9, but also that it is possible to customize and study spider silk production.

Don’t you hate it when making your DIY X-ray machine you make an uncomfortable amount of ozone gas? No? Well [Hyperspace Pirate] did, which made him come up with an interesting idea. While creating a high voltage supply for his very own X-ray machine, the high voltage corona discharge produced a very large amount of ozone. However, normally ozone is produced using lower voltage, smaller gaps, and large surface areas. Naturally, this led [Hyperspace Pirate] to investigate if a higher voltage method is effective at producing ozone.

Using a custom 150kV converter, [Hyperspace Pirate] was able to test the large gap method compared to the lower voltage method (dielectric barrier discharge). An ammonia reaction with the ozone allowed our space buccaneer to test which method was able to produce more ozone, as well as some variations of the designs.

Large 150kV gaps proved slightly effective but with no large gains, at least not compared to the dielectric barrier method. Of which, glass as the dielectric leads straight to holes, and HTPE gets cooked, but in the end, he was able to produce a somewhat sizable amount of ammonium nitrate. The best design included two test tubes filled with baking soda and their respective electrodes. Of course, this comes with the addition of a very effective ozone generator.

While this project is very thorough, [Hyperspace Pirate] himself admits the extreme dangers of high ozone levels, even getting close enough to LD50 levels for worry throughout out his room. This goes for when playing with high voltage in general kids! At the end of the day even with potential asthma risk, this is a pretty neat project that should probably be left to [Hyperspace Pirate]. If you want to check out other projects from a distance you should look over to this 20kW microwave to cook even the most rushed meals!

Thanks to [Mahdi Naghavi] for the Tip!

Some readers may recall building a line-following robot during their school days. Involving some IR LEDs, perhaps a bit of LEGO, and plenty of trial-and-error, it was fun on a tiny scale. Now imagine that—but rideable. That’s exactly what [Austin Blake] did, scaling up a classroom robotics staple into a full-size vehicle you can actually sit on.

The robot uses a whopping 32 IR sensors to follow a black line across a concrete workshop floor, adjusting its path using a steering motor salvaged from a power wheelchair. An Arduino Mega Pro Mini handles the logic, sending PWM signals to a DIY servo. The chassis consists of a modified Crazy Cart, selected for its absurdly tight turning radius. With each prototype iteration, [Blake] improved sensor precision and motor control, turning a bumpy ride into a smooth glide.

The IR sensor array, which on the palm-sized vehicle consisted of just a handful of components, evolved into a PCB-backed bar nearly 0.5 meters wide. Potentiometer tuning was a fiddly affair, but worth it. Crashes? Sure. But the kind that makes you grin like your teenage self. If it looks like fun, you could either build one yourself, or upgrade a similar LEGO project.

If legend is to be believed, three disparate social forces in early 20th-century America – the temperance movement, the rise of car culture, and the Scots-Irish culture of the South – collided with unexpected results. The temperance movement managed to get Prohibition written into the Constitution, which rankled the rebellious spirit of the descendants of the Scots-Irish who settled the South. In response, some of them took to the backwoods with stills and sacks of corn, creating moonshine by the barrel for personal use and profit. And to avoid the consequences of this, they used their mechanical ingenuity to modify their Fords, Chevrolets, and Dodges to provide the speed needed to outrun the law.

Though that story may be somewhat apocryphal, at least one of those threads is still woven into the American story. The moonshiner’s hotrod morphed into NASCAR, one of the nation’s most-watched spectator sports, and informed much of the car culture of the 20th century in general. Unfortunately, that led in part to our current fossil fuel predicament and its attendant environmental consequences, which are now being addressed by replacing at least some of the gasoline we burn with the same “white lightning” those old moonshiners made. The cost-benefit analysis of ethanol as a fuel is open to debate, as is the wisdom of using food for motor fuel, but one thing’s for sure: turning corn into ethanol in industrially useful quantities isn’t easy, and it requires some Big Chemistry to get it done.

Heavy on the Starch

As with fossil fuels, manufacturing ethanol for motor fuel starts with a steady supply of an appropriate feedstock. But unlike the drilling rigs and pump jacks that pull the geochemically modified remains of half-billion-year-old phytoplankton from deep within the Earth, ethanol’s feedstock is almost entirely harvested from the vast swathes of corn that carpet the Midwest US (Other grains and even non-grain plants are used as feedstock in other parts of the world, but we’re going to stick with corn for this discussion. Also, other parts of the world refer to any grain crop as corn, but in this case, corn refers specifically to maize.)

The corn used for ethanol production is not the same as the corn-on-the-cob at a summer barbecue or that comes in plastic bags of frozen Niblets. Those products use sweet corn bred specifically to pack extra simple sugars and less starch into their kernels, which is harvested while the corn plant is still alive and the kernels are still tender. Field corn, on the other hand, is bred to produce as much starch as possible, and is left in the field until the stalks are dead and the kernels have converted almost all of their sugar into starch. This leaves the kernels dry and hard as a rock, and often with a dimple in their top face that gives them their other name, dent corn.

Each kernel of corn is a fruit, at least botanically, with all the genetic information needed to create a new corn plant. That’s carried in the germ of the kernel, a relatively small part of the kernel that contains the embryo, a bit of oil, and some enzymes. The bulk of the kernel is taken up by the endosperm, the energy reserve used by the embryo to germinate, and as a food source until photosynthesis kicks in. That energy reserve is mainly composed of starch, which will power the fermentation process to come.

Starch is mainly composed of two different but related polysaccharides, amylose and amylopectin. Both are polymers of the simple six-carbon sugar glucose, but with slightly different arrangements. Amylose is composed of long, straight chains of glucose molecules bound together in what’s called an α-1,4 glycosidic bond, which just means that the hydroxyl group on the first carbon of the first glucose is bound to the hydroxyl on the fourth carbon of the second glucose through an oxygen atom:

Amylose chains can be up to about 500 or so glucose subunits long. Amylopectin, on the other hand, has shorter straight chains but also branches formed between the number one and number six carbon, an α-1,6 glycosidic bond. The branches appear about every 25 residues or so, making amylopectin much more tangled and complex than amylose. Amylopectin makes up about 75% of the starch in a kernel.

Slurry Time

Ethanol production begins with harvesting corn using combine harvesters. These massive machines cut down dozens of rows of corn at a time, separating the ears from the stalks and feeding them into a threshing drum, where the kernels are freed from the cob. Winnowing fans and sieves separate the chaff and debris from the kernels, which are stored in a tank onboard the combine until they can be transferred to a grain truck for transport to a grain bin for storage and further drying.

Once the corn is properly dried, open-top hopper trucks or train cars transport it to the distillery. The first stop is the scale house, where the cargo is weighed and a small sample of grain is taken from deep within the hopper by a remote-controlled vacuum arm. The sample is transported directly to the scale house for a quick quality assessment, mainly based on moisture content but also the physical state of the kernels. Loads that are too wet, too dirty, or have too many fractured kernels are rejected.

Loads that pass QC are dumped through gates at the bottom of the hoppers into a pit that connects to storage silos via a series of augers and conveyors. Most ethanol plants keep a substantial stock of corn, enough to run the plant for several days in case of any supply disruption. Ethanol plants operate mainly in batch mode, with each batch taking several days to complete, so a large stock ensures the efficiency of continuous operation.

To start a batch of ethanol, corn kernels need to be milled into a fine flour. Corn is fed to a hammer mill, where large steel weights swinging on a flywheel smash the tough pericarp that protects the endosperm and the germ. The starch granules are also smashed to bits, exposing as much surface area as possible. The milled corn is then mixed with clean water to form a slurry, which can be pumped around the plant easily.

The first stop for the slurry is large cooking vats, which use steam to gently heat the mixture and break the starch into smaller chains. The heat also gelatinizes the starch, in a process that’s similar to what happens when a sauce is thickened with a corn starch slurry in the kitchen. The gelatinized starch undergoes liquefaction under heat and mildly acidic conditions, maintained by injecting sulfuric acid or ammonia as needed. These conditions begin hydrolysis of some of the α-1,4 glycosidic bonds, breaking the amylose and amylopectin chains down into shorter fragments called dextrin. An enzyme, α-amylase, is also added at this point to catalyze the α-1,4 bonds to create free glucose monomers. The α-1,6 bonds are cleaved by another enzyme, α-amyloglucosidase.

The Yeast Get Busy

The result of all this chemical and enzymatic action is a glucose-rich mixture ready for fermentation. The slurry is pumped to large reactor vessels where a combination of yeasts is added. Saccharomyces cerevisiae, or brewer’s yeast, is the most common, but other organisms can be used too. The culture is supplemented with ammonia sulfate or urea to provide the nitrogen the growing yeast requires, along with antibiotics to prevent bacterial overgrowth of the culture.

Fermentation occurs at around 30 degrees C over two to three days, while the yeast gorge themselves on the glucose-rich slurry. The glucose is transported into the yeast, where each glucose molecule is enzymatically split into two three-carbon pyruvate molecules. The pyruvates are then broken down into two molecules of acetaldehyde and two of CO₂. The two acetaldehyde molecules then undergo a reduction reaction that creates two ethanol molecules. The yeast benefits from all this work by converting two molecules of ADP into two molecules of ATP, which captures the chemical energy in the glucose molecule into a form that can be used to power its metabolic processes, including making more yeast to take advantage of the bounty of glucose.

After the population of yeast grows to the point where they use up all the glucose, the mix in the reactors, which contains about 12-15% ethanol and is referred to as beer, is pumped into a series of three distillation towers. The beer is carefully heated to the boiling point of ethanol, 78 °C. The ethanol vapors rise through the tower to a condenser, where they change back into the liquid phase and trickle down into collecting trays lining the tower. The liquid distillate is piped to the next two towers, where the same process occurs and the distillate becomes increasingly purer. At the end of the final distillation, the mixture is about 95% pure ethanol, or 190 proof. That’s the limit of purity for fractional distillation, thanks to the tendency of water and ethanol to form an azeotrope, a mixture of two or more liquids that boils at a constant temperature. To drive off the rest of the water, the distillate is pumped into large tanks containing zeolite, a molecular sieve. The zeolite beads have pores large enough to admit water molecules, but too small to admit ethanol. The water partitions into the zeolite, leaving 99% to 100% pure (198 to 200 proof) ethanol behind. The ethanol is mixed with a denaturant, usually 5% gasoline, to make it undrinkable, and pumped into storage tanks to await shipping.

Nothing Goes to Waste

The muck at the bottom of the distillation towers, referred to as whole stillage, still has a lot of valuable material and does not go to waste. The liquid is first pumped into centrifuges to separate the remaining grain solids from the liquid. The solids, called wet distiller’s grain or WDG, go to a rotary dryer, where hot air drives off most of the remaining moisture. The final product is dried distiller’s grain with solubles, or DDGS, a high-protein product used to enrich animal feed. The liquid phase from the centrifuge is called thin stillage, which contains the valuable corn oil from the germ. That’s recovered and sold as an animal feed additive, too.

The final valuable product that’s recovered is the carbon dioxide. Fermentation produces a lot of CO₂, about 17 pounds per bushel of feedstock. The gas is tapped off the tops of the fermentation vessels by CO₂ scrubbers and run through a series of compressors and coolers, which turn it into liquid carbon dioxide. This is sold off by the tanker-full to chemical companies, food and beverage manufacturers, who use it to carbonate soft drinks, and municipal water treatment plants, where it’s used to balance the pH of wastewater.

There are currently 187 fuel ethanol plants in the United States, most of which are located in the Midwest’s corn belt, for obvious reasons. Together, these plants produced more than 16 billion gallons of ethanol in 2024. Since each bushel of corn yields about 3 gallons of ethanol, that translates to an astonishing 5 billion bushels of corn used for fuel production, or about a third of the total US corn production.

Automotive racing is a grueling endeavor, a test of one’s mental and physical prowess to push an engineered masterpiece to its limit. This is all the more true of 24 hour endurance races where teams tag team to get the most laps of a circuit in over a 24 hour period. The format pushes cars and drivers to the very limit. Doing so on a $500 budget as presented by the 24 hours of Lemons makes this all the more impressive!

Of course, racing on a $500 budget is difficult to say the least. All the expected Fédération Internationale de l’Automobile (FIA) safety requirements are still in place, including roll cage, seats and fire extinguisher. However, brakes, wheels, tires and safety equipment are not factored into the cost of the car, which is good because an FIA racing seat can run well in excess of the budget. Despite the name, most races are twelve to sixteen hours across two days, but 24 hour endurance races are run. The very limiting budget and amateur nature of the event has created a large amount of room for teams to get creative with car restorations and race car builds.

One such team we had the chance of speaking to goes by the name 24 Hours of Le-Mines. Their build is a wonderful mishmash of custom fabrication and affordable parts. It’s built from a restored 1999 NA Miata complete with rusted frame and all! Power is handled by a rebuilt 302 Mustang engine of indeterminate age.

The stock Miata brakes seem rather small for a race car, but are plenty for a car of its weight. Suspension is an Amazon special because it only has to work for 24 hours. The boot lid (or trunk if you prefer) is held down with what look to be over-sized RC car pins. Nestled next to the PVC pipe inlet pipe is a nitrous oxide canister — we don’t know if it’s functional or for show, but we like it nonetheless. The scrappy look is completed with a portion of the road sign fabricated into a shifter cover.

The team is unsure if the car will end up racing, but odds are if you are reading Hackaday, you care more about the race cars then the actual racing. Regardless, we hope to see this Miata in the future!

This is certainly not the first time we have covered 24 hour endurance engineering, like this solar powered endurance plane.

Taking a break from his usual prodding at suspicious AliExpress USB chargers, [DiodeGoneWild] recently had a gander at what used to be a good USB charger.

Before it went completely dead, the Anker 737 GaNPrime USB charger which a viewer sent him was capable of up to 120 Watts combined across its two USB-C and one USB-A outputs. Naturally the charger’s enclosure couldn’t be opened non-destructively, and it turned out to have (soft) potting compound filling up the voids, making it a treat to diagnose. Suffice it to say that these devices are not designed to be repaired.

With it being an autopsy, the unit got broken down into the individual PCBs, with a short detected that eventually got traced down to an IC marked ‘SW3536’, which is one of the ICs that communicates with the connected USB device to negotiate the voltage. With the one IC having shorted, it appears that it rendered the entire charger into an expensive paperweight.

Since the charger was already in pieces, the rest of the circuit and its ICs were also analyzed. Here the gallium nitride (GaN) part was found in the Navitas GaNFast NV6136A FET with integrated gate driver, along with an Infineon CoolGaN IGI60F1414A1L integrated power stage. Unfortunately all of the cool technology was rendered useless by one component developing a short, even if it made for a fascinating look inside one of these very chonky USB chargers.

Although plenty of us have our preferred language for coding, whether it’s C for its hardware access, Python for its usability, or Fortran for its mathematic prowess, not every language is specifically built for problem solving of a particular nature. Some are built as thought experiments or challenges, like Whitespace or Chicken but aren’t used for serious programming. There are a few languages that fit in the gray area between these regions, and one example of this is MOUSE, which can now be run on an Arduino.

Although MOUSE was originally meant to be a minimalist language for computers of the late 70s and early 80s with limited memory (even for the era), its syntax looks more like a more modern esoteric language, and indeed it arguably would take a Python developer a bit of time to get used to it in a similar way. It’s stack-based, for a start, and also uses Reverse Polish Notation for performing operations. The major difference though is that programs process single letters at a time, with each letter corresponding to a specific instruction. There have been some changes in the computing world since the 80s, though, so [Ivan]’s version of MOUSE includes a few changes that make it slightly different than the original language, but in the end he fits an interpreter, a line editor, graphics primitives, and peripheral drivers into just 2 KB of SRAM and 32 KB Flash so it can run on an ATmega328P.

There are some other features here as well, including support for PS/2 devices, video output, and the ability to save programs to the internal EEPROM. It’s an impressive setup for a language that doesn’t get much attention at all, but certainly one that threads the needle between usefulness and interesting in its own right. Of course if a language where “Hello world” is human-readable is not esoteric enough, there are others that may offer more of a challenge.

Image Credit: Maxbrothers2020

Although the idea of containing a plasma within a magnetic field seems straightforward at first, plasmas are highly dynamic systems that will happily escape magnetic confinement if given half a chance. This poses a major problem in nuclear fusion reactors and similar, where escaping particles like alpha (helium) particles from the magnetic containment will erode the reactor wall, among other issues. For stellarators in particular the plasma dynamics are calculated as precisely as possible so that the magnetic field works with rather than against the plasma motion, with so far pretty good results.

Now researchers at the University of Texas reckon that they can improve on these plasma system calculations with a new, more precise and efficient method. Their suggested non-perturbative guiding center model is published in (paywalled) Physical Review Letters, with a preprint available on Arxiv.

The current perturbative guiding center model admittedly works well enough that even the article authors admit to e.g. Wendelstein 7-X being within a few % of being perfectly optimized. While we wouldn’t dare to take a poke at what exactly this ‘data-driven symmetry theory’ approach exactly does differently, it suggests the use machine-learning based on simulation data, which then presumably does a better job at describing the movement of alpha particles through the magnetic field than traditional simulations.

Top image: Interior of the Wendelstein 7-X stellarator during maintenance.

Our hacker [Andrew Zonenberg] reports in on his open-source high-speed Ethernet switch. He hasn’t finished yet, but progress has been made.

If you were wondering what might be involved in a high-speed Ethernet switch implementation look no further. He’s been working on this project, on and off, since 2012. His design now includes a dizzying array of parts. [Andrew] managed to snag some XCKU5P FPGAs for cheap, paying two cents in the dollar, and having access to this fairly high-powered hardware affected the project’s direction.

You might be familiar with [Andrew Zonenberg] as we have heard from him before. He’s the guy who gave us the glscopeclient, which is now ngscopeclient.

As perhaps you know, when he says in his report that he is an “experienced RTL engineer”, he is talking about Register-Transfer Level, which is an abstraction layer used by hardware description languages, such as Verilog and VHDL, which are used to program FPGAs. When he says “RTL” he’s not talking about Resistor-Transistor Logic (an ancient method of developing digital hardware) or the equally ancient line of Realtek Ethernet controllers such as the RTL8139.

When it comes to open-source software you can usually get a copy at no cost. With open-source hardware, on the other hand, you might find yourself needing to fork out for some very expensive bits of kit. High speed is still expensive! And… proprietary, for now. If you’re looking to implement Ethernet hardware today, you will have to stick with something slower. Otherwise, stay tuned, and watch this space.

For all that “should have used a 555” is a bit of a meme around here, there’s some truth to it. The humble 555 is a wonderful tool in the right hands. That’s why it’s wonderful to see this all-analog stylus synth project by EE student [DarcyJ] bringing the 555 out for the new generation.

The project is heavily inspired by the vintage stylophone, but has some neat tweaks. A capacitor bank means multiple octaves are available, and using a ladder of trim pots instead of fixed resistors makes every note tunable. [Darcy] of course included the vibrato function of the original, but no, he did not use a 555 for that, too. He used an RC oscillator. He put a trim pot on that, too, to control the depth of vibrato, which we don’t recall seeing on the original stylophone.

The writeup is very high quality and could be recommended to anyone just getting started in analog (or analogue) electronics– not only does [Darcy] explain his design process, he also shows his pratfalls and mistakes, like in the various revisions he went through before discovering the push-pull amplifier that ultimately powers the speaker.

Since each circuit is separately laid out and indicated on the PCB [Darcy] designed in KiCad for this project. Between that and everything being thru-hole, it seems like [Darcy] has the makings of a lovely training kit. If you’re interested in rolling your own, the files are on GitHub under a CERN-OHL-S v2 license,  and don’t forget to check out the demo video embedded below to hear it in action.

Of course, making music on the 555 is hardly a new hack. We’ve seen everything from accordions to paper-tape player pianos to squonkboxes over the years. Got another use for the 555? Let us know about it, in the inevitable shill for our tip line you all knew was coming.

There was a period in the 1990s when it seemed like the personal data assistant (PDA) was going to be the device of the future. If you were lucky you could afford a Psion, a PalmPilot, or even the famous Apple Newton — but to trap the unwary there were a slew of far less capable machines competing for market share.

[Nick Bild] has one of these, branded Rolodex, and in a bid to make using a generative AI less alluring, he’s set it up as the interface to an LLM hosted on a Raspberry Pi 400. This hack is thus mostly a tale of reverse engineering the device’s serial protocol to free it from its Windows application.

Finding the baud rate was simple enough, but the encoding scheme was unexpectedly fiddly. Sadly the device doesn’t come with a terminal because these machines were very much single-purpose, but it does have a memo app that allows transfer of text files. This is the wildly inefficient medium through which the communication with the LLM happens, and it satisfies the requirement of making the process painful.

We see this type of PDA quite regularly in second hand shops, indeed you’ll find nearly identical devices from multiple manufacturers also sporting software such as dictionaries or a thesaurus. Back in the day they always seemed to be advertised in Sunday newspapers and aimed at older people. We’ve never got to the bottom of who the OEM was who manufactured them, or indeed cracked one apart to find the inevitable black epoxy blob processor. If we had to place a bet though, we’d guess there’s an 8051 core in there somewhere.

Here’s something fun. Our hacker [Willow Cunningham] has sent us a copy of his homework. This is his final project for the “ECE 574: Cluster Computing” course at the University of Maine, Orono.

It was enjoyable going through the process of having a good look at everything in this project. The project is a “cluster” of 5x Raspberry Pi Pico microcontrollers — with one head node as the leader and four compute nodes that work on tasks. The software for the both types of node is written in C. The head node is connected to a workstation via USB 1.1 allowing the system to be controlled with a Python script.

The cluster is configured to process an embarrassingly parallel image convolution. The input image is copied into the head node via USB which then divvies it up and distributes it to n compute nodes via I²C, one node at a time. Results are given for n = {1,2,4} compute nodes.

It turns out that the work of distributing the data dwarfs the compute by three orders of magnitude. The result is that the whole system gets slower the more nodes we add. But we’re not going to hold that against anyone. This was a fascinating investigation and we were impressed by [Willow]’s technical chops. This was a complicated project with diverse hardware and software challenges and he’s done a great job making it all work and in the best scientific tradition.

It was fun reading his journal in which he chronicled his progress and frustrations during the project. His final report in IEEE format was created using LaTeX and Overleaf, at only six pages it is an easy and interesting read.

For anyone interested in cluster tech be sure to check out the 256-core RISC-V megacluster and a RISC-V supercluster for very low cost.

Although Nintendo is mostly famous for making great games, they also have an infamous reputation for being highly litigious not only for reasonable qualms like outright piracy of their games, but additionally for more gray areas like homebrew development on their platforms or posting gameplay videos online. With that sort of reputation it’s not surprising that they don’t release open-source drivers for their platforms, especially those like the Wii U with unique controllers that are difficult to emulate. This Wii U gamepad emulator seeks to bridge that gap.

The major issue with the Wii U compared to other Nintendo platforms like the SNES or GameCube is that the controller looks like a standalone console and behaves similarly as well, with its own built-in screen. Buying replacement controllers for this unusual device isn’t straightforward either; outside of Japan Nintendo did not offer an easy path for consumers to buy controllers. This software suite, called Vanilla, aims to allow other non-Nintendo hardware to bridge this gap, bringing in support for things like the Steam Deck, the Nintendo Switch, various Linux devices, or Android smartphones which all have the touch screens required for Wii U controllers. The only other hardware requirement is that the device must support 802.11n 5 GHz Wi-Fi.

Although the Wii U was somewhat of a flop commercially, it seems to be experiencing a bit of a resurgence among collectors, retro gaming enthusiasts, and homebrew gaming developers as well. Many games were incredibly well made and are still experiencing continued life on the Switch, and plenty of gamers are looking for the original experience on the Wii U instead. If you’ve somehow found yourself in the opposite position of owning of a Wii U controller but not the console, though, you can still get all the Wii U functionality back with this console modification.

Thanks to [Kat] for the tip!

Within the nuclear sciences, including fuel production and nuclear medicine (radiopharmaceuticals), often specific isotopes have to be produced as efficiently as possible, or allow for the formation of (gaseous) fission products and improved cooling without compromising the fuel. Here having the target material possess an optimized 3D shape to increase surface area and safely expel gases during nuclear fission can be hugely beneficial, but producing these shapes in an efficient way is complicated. Here using photopolymer-based stereolithography (SLA) as  recently demonstrated by [Alice Zanini] et al. with a research article in Advanced Functional Materials provides an interesting new method to accomplish these goals.

In what is essentially the same as what a hobbyist resin-based SLA printer does, the photopolymer here is composed of uranyl ions as the photoactive component along with carbon precursors, creating solid uranium dicarbide (UC₂) structures upon exposure to UV light with subsequent sintering. Uranium-carbide is one of the alternatives being considered for today’s uranium ceramic fuels in fission reactors, with this method possibly providing a reasonable manufacturing method.

Uranium carbide is also used as one of the target materials in ISOL (isotope separation on-line) facilities like CERN’s ISOLDE, where having precise control over the molecular structure of the target could optimize isotope production. Ideally equivalent photocatalysts to uranyl can be found to create other optimized targets made of other isotopes as well, but as a demonstration of how SLA (DLP or otherwise) stands to transform the nuclear sciences and industries.

A lot of projects we see around here are built not just because they can be built, but because there’s no other option available. Necessity is the mother of invention, as they say. And for [Jeff] who has many thousands of dollars of food stowed in a chest freezer, his need for something to keep track of his freezer’s status was greater than any commercial offering available. Not only are freezers hard on batteries, they’re hard on WiFi signals as well, so [Jeff] built his own temperature monitor to solve both of these issues.

The obvious solution here is to have a temperature probe that can be fished through the freezer in some way, allowing the microcontroller, battery, and wireless module to operate outside of the harsh environment. [Jeff] is using K-type thermocouples here, wired through the back of the freezer. This one also is built into a block of material which allows him to get more diffuse temperature readings than a standard probe would provide. He’s also solving some other problems with commercially available probes here as well, as many of them require an Internet connection or store data in a cloud. To make sure everything stays local, he’s tying this in to a Home Assistant setup which also allows him to easily make temperature calibrations as well as notify him if anything happens to the freezer.

Although the build is very robust (or, as [Jeff] himself argues, overengineered) he does note that since he built it there have been some additional products offered for sale that fit this niche application. But even so, we always appreciate the customized DIY solution that avoids things like proprietary software, subscriptions, or cloud services. We also appreciate freezers themselves; one of our favorites was this restoration of a freezer with a $700,000 price tag.