Making A Wax Motor For Micrometer-Level Control

November 4, 2026 by Maya Posch 13 Comments

Although not very glamorous, wax motors are a fairly common type of linear actuator. They use the thermal response of waxes and the resulting volumetric expansion or reduction to create a relatively fast, smooth, and highly predictable actuator that can work for decades. They can often be found operating valves and things like the door mechanisms of washing machines. As [BubsBuilds] demonstrates in a recent video, you can even build your own wax motor for very precise control.

Here simple paraffin wax is used, which changes in volume by 1.15 times when it goes from solid to its molten state. Calling it a ‘waxtuator’, [BubsBuilds] characterized this expansion rate over the temperature range between solid and fully molten to make it a controllable actuator. In his experiments, a gap of less than 5 µm was maintained over twelve hours, showing how precise this device can be if you can control the temperature that the wax is kept at.

One major issue is the low conductivity of paraffin wax, which as some commentators remark can be solved by mixing something like fine copper particles into the wax to increase the thermal conductivity. In the shown implementation instead multiple channels in the aluminium block are used, which are melted by a TEC element.

The wax exerts pressure on a working fluid, which then pushes on a hydraulic cylinder that can be used for whatever precise linear actuating task has to be performed. Although initially water was used as a working fluid, this posed many issues with wax-water interface compatibility and vacuum degassing.

Although ethylene glycol makes for a better working fluid, this proved to be its own hassle. With the water-wax version a displacement sensor was thus used to measure and calibrate the whole setup. The electronics used to control the TEC in combination with the current temperature and displacement are a story in itself, but essential for making this device work.

While not something we often see tackled in the DIY space, we’ve covered a few teardowns of commercial units over the years.

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From Germanium To Diamond: The Many Shapes Of Semiconductors

November 4, 2026 by Maya Posch 5 Comments

It seems fair to say that semiconductor technology has been one of the most influential inventions in human history. Practically overnight it turned human technology from being large, cumbersome and power-hungry into an increasingly sleeker, more power-efficient and much more capable form. It has become practically impossible at this point to imagine modern society without semiconductor technology.

That said, we didn’t always use today’s silicon-based semiconductor technology, and although silicon-based semiconductors are exceedingly versatile and adaptable, they do have their limitations. The past years we have seen for example gallium-nitride semiconductors make big inroads in power switching technology, and more exotic forms like diamond-based semiconductors keep making their tantalizing appearances.

In this article we’ll take a look at how we ended up at silicon as the default for semiconductor technology, as well as why we may want to consider moving to other materials.

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Using A Cheap DC Motor To Make A Go-Kart Go

November 4, 2026 by Maya Posch 12 Comments

Where Archimedes said that he could move the Earth given a large enough lever and a suitable fulcrum, [Current Concept] decided that he could give his own spin on this quote by swapping the lever and fulcrum for a tiny $1 DC brushed motor and a very large gearing ratio.

In addition to 3D printing a compound gearbox with the requisite 1,243:1 gear ratio, the video also covers the joys of getting a ‘Craigslist special’ go-kart for about the same price as the electric motor and having to undo many very special modifications.

With that done, the newly printed gearbox was installed, along with the single DC motor to drive it all. This actually managed to propel the go-kart, at a pace that would impress even a snail, so for the next phase instead of a single motor a total of fourteen were used, all adding their tiny bit of torque into the gearbox.

Although one has to keep in mind that the gearbox and chain mechanism will also take its slice of the provided energy along with other inefficiencies, one still cannot beat the laws of physics. Much like Archimedes’ lever powered by a piddly human, the conversion of RPM into torque for these small motors was never going to get you that zippy go-kart experience.

Which isn’t to say that someone shouldn’t totally put some BLDC motors to the task and see how fast a go-kart can be made to move using those and an optimized gearbox.

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Detecting An Eight Magnetic Pole State Using Chiral Phonons

November 3, 2026 by Maya Posch 5 Comments

The idea that magnetism doesn’t necessarily always have a dipolar configuration is not a new one, but it’s not an easy theory to find evidence for. Most recently a team of scientists at the University of Toronto used a new method involving vibrational energy in the form of phonons to find evidence for an octupolar magnetic order.

In the associated paper in Physical Review Letters (paywalled, arXiv version) by [Ruairidh Sutcliffe] et al. we can find more details on this method and what their findings may mean for various fields. Naturally, this is a quantum-level phenomenon that requires Raman spectroscopy to be detectable via said phonons.

The materials investigated here are also somewhat exotic, ranging from actinides like NpO₂ to transition metal oxides like Sr₂MgReO₆, while having on common strong spin-orbit coupling. Where the phonons come into play is that they can be used to indirectly measure crystal lattice distortions due to the pseudo-angular momentum assigned to the phonons. This generates pseudo-chiral phonons which then show up in the Raman spectroscopy.

Although finding evidence for octopolar magnetic order is interesting in itself, this way to measuring a crystal lattice’s structure makes for another fascinating research tool that can be used to study many similar phenomenon.

These quantum-level magnetic states could conceivably be used for anything from sensors to magnetic data storage, though any such research is unlikely to be commercialized any time soon.

The Components For Life May Not Have Arrived By Comet

November 3, 2026 by Maya Posch 15 Comments

When it comes to abiogenesis, i.e. the formation of the first biological cells on Earth, there are many theories on how this got kickstarted. One of the more popular theories involves the primordial Earth being seeded with the organic building blocks by comets hurtling through the atmosphere. Although organic compounds have been discovered on such comets, the question of whether these compounds could survive hurtling through Earth’s atmosphere and the rapid deceleration upon impact remained unanswered.

Hydrothermal vent in the Atlantic Ocean. (Source: NOAA)

Now a study by [Richard J. Anslow] et al. in Scientific Reports posits that the answer here is a very probable ‘no’. Using detailed cometary impact simulations and our current understanding of the formation and presence of these volatile organic molecules on comets it was found that the possibility of such molecules surviving the impact was extremely low.

The focus here was on hydrogen cyanide (HCN), with simulations showing a negligible amount of it surviving to make it onto Earth’s surface. Naturally from there other influences like hydrolysis will further dilute and degrade such molecules, making their effect on any biological activity highly unlikely. Meanwhile this comet-based delivery method was much more effective on a historical Mars – one capable of retaining liquid water – with more than five times successful deliveries of HCN.

Realistically, the much more likely source of such ingredients and the energy for the formation of the first biological cells on Earth would have been found near hydrothermal vents, which even today provide a rich mixture of chemicals that sustains entire ecosystems that are quite unlike those found here on the surface. For smaller planets like Mars the cometary route could however been a viable method for biological activity, which provides exciting prospects for similar bodies like Europa once we start exploring its oceans.

Flying An RC Airplane With Twin Airblower EDFs

November 2, 2026 by Maya Posch 14 Comments

Shortly after [RCMakerLab] posted his question on potentially equipping an RC airplane with the electronic ducted fans (EDFs) from those airblower devices – are sold mostly as a replacement for canned air – the comment sections pretty much exploded with comments that he should just have strapped them onto an RC airplane and see for himself. In a new video this is exactly what is done, creating a somewhat A-10 Warthog-esque RC plane with its twin EDF turbines.

After we first covered this journey, the next question that got answered in the subsequent video was whether replacing the default electronic speed control (ESC) would make sense, mostly to lighten the load and optimize it for use with a typical RC avionics controller. This turned out to be the case, and thus it’s time for a test flight.

The aircraft created from largely styrofoam board seems to be largely designed for stability, with its large wings and the very A-10-like placement of the turbines right above the tail with its twin vertical stabilizers. It wasn’t really a shocker to see that the resulting 368 gram light airplane actually flies pretty well, with it taking off almost immediately.

With the used 2S1P, 1300 mAh Li-Po battery total flight time is about 3-4 minutes, which seems about on par with typical numbers. With a larger airplane and battery these two EDFs probably could be pushed even further, which we fully expect to see in a future video.

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Investigating Whether Zener Diodes Work For ESD Protection

November 2, 2026 by Maya Posch 14 Comments

Sometimes the naming of parts in electronics can contribute to confusion about what they are good for, with the topic of Zener diodes in the context of fast surges like those from electrostatic discharge (ESD) being a good example. In a recent video by [BTT Lab] this particular question regarding Zener suitability for suppressing ESD is addressed, as compared to transient-voltage-suppression (TVS) diodes.

The main argument against using Zener diodes for ESD and similar surge suppression is that they react too slowly, which obviously gives said surge time to cause some real damage. This is where a special form of avalanche effect-based diodes called TVS diodes are recommended, as their response time is in the picoseconds rather than nanoseconds or slower as for Zener diodes.

Although this is technically true, as also pointed out in the video, a Zener diode also uses the avalanche effect, with the diode starting off conducting in the reverse direction using the Zener effect before transitioning to the much faster avalanche effect. The transition point is hereby determined by how heavily the p-n junction is doped, making effectively all Zener diodes also avalanche diodes.

TVS diodes consequently are basically Zener diodes that are optimized for a very early transition to said avalanche effect. They are also generally larger than typical Zener diodes as they generate a lot of internal thermal energy while in reverse conducting mode, which has to be contained and shed without causing permanent damage.

The short version is thus that diodes marked as ‘TVS’ are the best choice for surge protection, while those marked as ‘Zener’ are best used for voltage clamping, reference voltages and all other typical Zener diode things.

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