Building And Testing A Turbine Driven Hydro Generator

December 18, 2025 by Maya Posch 25 Comments

The theory behind hydropower is very simple: water obeys gravity and imparts the gained kinetic energy onto a turbine, which subsequently drives a generator. The devil here is, of course, in all the details, as [FarmCraft101] on YouTube is in the process of finding out as he adds a small hydro plant to his farm dam. After previously doing all the digging and laying of pipe, in this installment, the goal is to build and test the turbine and generator section so that it can be installed.

The turbine section is 3D-printed and slides onto the metal shaft, which then protrudes from the back where it connects to a 230VAC, three-phase generator. This keeps it quite modular and easy to maintain, which, as it turns out, is a very good idea. After a lot of time spent on the lathe, cutting metal, and tapping threads, the assembled bulk of the system is finally installed for its first test run.

After all that work, the good news is that the 3D-printed turbine seems to work fine and holds up, producing a solid 440 RPM. This put it over the predicted 300 RPM, but that’s where the good news ends. Although the generator produces 28 watts, it’s officially rated for 3 kW at 300 RPM. Obviously, with the small size of this AliExpress-special, the expectation was closer to 750 watts, so that required a bit of investigation. As it turns out, at 300 RPM it only produces 9 watts, so obviously the generator was a dud despite cashing out $230 for it.

Hopefully, all it takes to fix this is to order a new generator to get this hydropower setup up and running. Fortunately, it seems that he’ll be getting his money back from the dud generator, so hopefully in the next video we’ll see the system cranking out something closer to a kilowatt of power.

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Bare Metal STM32: Increasing The System Clock And Running Dhrystone

December 18, 2025 by Maya Posch 9 Comments

When you start an STM32 MCU with its default configuration, its CPU will tick along at a leisurely number of cycles on the order of 8 to 16 MHz, using the high-speed internal (HSI) clock source as a safe default to bootstrap from. After this phase, we are free to go wild with the system clock, as well as the various clock sources that are available beyond the HSI.

Increasing the system clock doesn’t just affect the CPU either, but also affects the MCU’s internal buses via its prescalers and with it the peripherals like timers on that bus. Hence it’s essential to understand the clock fabric of the target MCU. This article will focus on the general case of increasing the system clock on an STM32F103 MCU from the default to the maximum rated clock speed using the relevant registers, taking into account aspects like Flash wait states and the APB and AHB prescalers.

Although the Dhrystone benchmark is rather old-fashioned now, it’ll be used to demonstrate the difference that a faster CPU makes, as well as how complex accurately benchmarking is. Plus it’s just interesting to get an idea of how a lowly Cortex-M3 based MCU compares to a once top-of-the line Intel Pentium 90 CPU.

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Building A Flying Blended Wing Body Aircraft Prototype

December 17, 2025 by Maya Posch 16 Comments

Anyone with an inkling of interest in super-sized remote control aircraft probably has at least seen some of the mind-blowing projects that [Ramy RC] has worked on over the years, with examples like the ongoing Airbus A380-800 build approaching the size of a full-sized business jet. That said, they recently got the offer to build a flying prototype of the Natilus Horizon, a blended wing body (BWB) aircraft that’s currently being developed into a full-sized production aircraft.

Suffice it to say that BWB RC aircraft isn’t something that they have built before, but as co-founder of Natilus, [Aleksey Matyushev], explains, they want to prove in this manner that building scale prototypes of future production aircraft is not nearly as complex as it’s often made out to be. Meaning that even two blokes in a shed as is the case here should be able to pull it off.

Natilus was founded in 2016 amidst strongly rising interest in these BWB aircraft designs that may one day threaten today’s tubes-with-wings. Their Kona design would be the cargo version and this Horizon prototype that [Ramy RC] is building the passenger version.

In this first video of two total, we can see the CAD project of the prototype and how the basic aircraft structure is being constructed out of carbon fiber composite, wood and foam. To this the engine nacelles, landing gear and wings are mounted, readying it for its maiden flight. The Natilus engineers have previously done all the simulations that should mean that it’ll fly like a glider, but we will have to wait until the next video to see whether that is the case.

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The Lethal Danger Of Combining Welding And Brake Cleaner

December 17, 2025 by Maya Posch 57 Comments

With the availability of increasingly cheaper equipment, welding has become far more accessible these days. While this is definitely a plus, it also comes with the elephant-sized asterisk that as with any tool you absolutely must take into account basic safety precautions for yourself and others. This extends to the way you prepare metal for welding, with [Dr. Bernard], AKA [ChubbyEmu] recently joining forces with [styropyro] to highlight the risks of cleaning metal with brake cleaner prior to welding.

Much like with common household chemicals used for cleaning, such as bleach and ammonia, improper use of these can produce e.g. chlorine gas, which while harmful is generally not lethal. Things get much more serious with brake cleaner, containing tetrachloroethylene. As explained in the video, getting brake cleaner on a rusty part to clean it and then exposing it to the intensive energies of the welding process suffices to create phosgene.

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Thorium-Metal Alloys And Radioactive Jet Engines

December 16, 2025 by Maya Posch 36 Comments

Although metal alloys is not among the most exciting topics for most people, the moment you add the word ‘radioactive’, it does tend to get their attention. So too with the once fairly common Mag-Thor alloys that combine magnesium with thorium, along with other elements, including zinc and aluminium. Its primary use is in aerospace engineering, as these alloys provide useful properties such as heat resistance, high strength and creep resistance that are very welcome in e.g. jet engines.

Most commonly found in the thorium-232 isotope form, there are no stable forms of this element. That said, Th-232 has a half-life of about 14 billion years, making it only very weakly radioactive. Like uranium-238 and uranium-235 it has the unique property of not having stable isotopes and yet still being abundantly around since the formation of the Earth. Thorium is about three times as abundant as uranium and thus rather hard to avoid contact with.

This raises the question of whether thorium alloys are such a big deal, and whether they justify removing something like historical artefacts from museums due to radiation risks, as has happened on a few occasions.

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After Decades, Linux Finally Gains Stable GPIB Support

December 16, 2025 by Maya Posch 40 Comments

Recently, [Greg Kroah-Hartman] proclaimed the joyous news on the Linux Kernel Mailing List that stable General Purpose Interface Bus (GPIB) support has finally been merged into the 6.19 Linux kernel.

The GPIB is a short-range 8-bit, multi-master interface bus that was standardized as IEEE 488. It first saw use on HP laboratory equipment in the 1970s, but was soon after also used by microcomputers like the Commodore PET, Commodore 64 and others. Although not high-speed with just 8 MB/s, nor with galvanic isolation requirements, it’s an uncomplicated bus design that can be implemented without much of a blip on the BOM costs.

The IEEE 488 standard consists of multiple elements, with 488.1 defining the physical interface and 488.2 the electrical protocol. Over the decades a communication protocol was also developed, in the form of SCPI and its standardized way of communicating with a wide range of devices using a simple human-readable protocol.

Although the physical side of IEEE 488 has changed over the years, with Ethernet becoming a major alternative to the short GPIB cables and large connectors, the electrical protocol and SCPI alike are still very much relevant today. This latest addition to the Linux kernel should make it much easier to use both old and new equipment equipped with this bus.

Building A Commodore 64 Laptop

December 15, 2025 by Maya Posch 31 Comments

What might a laptop version of the Commodore 64 have looked like if one had been released by the late 1980s? This is the question that [Kevin Noki] tried to recently answer with a custom C64 laptop build.

While technically you could argue that Commodore’s SX-64 could be construed as a ‘portable’ system, its bulky format ensured that it was only portable in the sense that a 1980s CRT-based oscilloscope is also portable. Sadly, this turned out to be the last real attempt by Commodore to make a portable non-PC compatible system, with the ill-fated Commodore LCD project never making it out of development. We can, however, glean from this some design hints of what Commodore’s designers had in mind.

Interestingly, [Kevin] decided to instead use the Macintosh Portable as inspiration, with adaptations to make it look more like a breadbin C64. One could have argued that the C64C’s design would have worked better. Regardless, an enclosure was 3D printed, with parts glued together and metal dowels added for support.

For the guts, a custom keyboard with a new PCB and FDM printed keycaps was used, with a Raspberry Pi Pico as keyboard controller. We would here cue the jokes about how the keyboard controller is more powerful than a C64, but the real brains of this laptop come in the form of a Raspberry Pi 5 SBC for running the Vice C64 emulator, which blows a C64 even further out of the water.

This choice also means there’s no direct compatibility with genuine C64 peripherals, but a workaround involving many adaptors and more MCUs was implemented. Sadly, cartridge compatibility was sacrificed due to these complications. The resulting innards can be glimpsed in the above screenshot to give some idea of what the end result looks like.

Of course, this isn’t the first time a Commodore 64 laptop has been created; [Ben Heck] used a C64C mainboard and an original keyboard back in 2009. This meant direct compatibility with all peripherals, including cartridges. Hopefully, now that Commodore as a company has been revived, it will pick up on ideas like these, as an FPGA-based C64 or C128 laptop would be pretty rad.

Thanks to [fluffy] for the tip.

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