Faraday Effects Emerging From The Optical Magnetic Field

January 6, 2026 by Maya Posch 8 Comments

As an electromagnetic radiation phenomenon, it’s perhaps not so surprising that light is affected by a magnetic field. This Faraday effect (FE) has been used since its discovery by [Michael Faraday] in 1845 for a wide range of applications, allowing for the manipulation of light’s polarization, something which is very useful in the field of optics, for remote sensing and spintronics. Despite this being such a well-known property of EM radiation a recent study claims to have made a new discovery here, with what they claim is about the ‘optical magnetic field’.

Their central claim is that it is not just the electrical component that contributes to the FE, but also the magnetic one, due to Zeeman energy that expresses itself from the magnetic component as a form of inverse FE. Based on their experimental findings they estimate that it contributes to the final measured FE by about 17% at a wavelength of 800 nm.

While definitely a very niche physics paper, and with no immediate implications, if independently confirmed it could deepen our understanding of the Faraday effect, and how to use it in future technologies.

The Many Questions And Challenges With DIY Hydroelectric Generators

January 6, 2026 by Maya Posch 29 Comments

The concept of building your own hydroelectric generator seems simple at face value: use gravity to impart as much force as possible onto a turbine, which spins a generator, thus generating electricity. If you’re like the bloke over at [FarmCraft101] trying to DIY this with your farm pond and a lot of PVC pipes, you may have some significantly more in-depth questions, especially pertaining to what kind of generator to use. This and other questions, some of which were raised after the previous video in which the first prototype generator was assembled, are answered in this follow-up video.

When you DIY such a hydroelectric system, you have a number of options when it comes to just the turbine design alone, with the Kaplan-style turbine being one of the most straightforward ones – especially if you use a fixed pitch instead of adjustable – but you can go pretty far in the weeds with alternatives. As for the sharp drop-off after the turbine in the used design, the technical term is a draft tube, which is actually more efficient in this kind of low head, high flow hydroelectric dam situation.

After getting his money back for the unusable ‘3 kW’ generator, there were three options left: try an EBay special, get a purpose-built one from a US company, or rewind an alternator stator for higher voltage output than the standard 12/24V. Ultimately option four was chosen, as in ‘all of the above’, so that comparison is coming up in a future video.

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Tired Of Burnt Fingers? Try PID Tuning The Hot Glue Gun

January 6, 2026 by Tyler August 19 Comments

Hot glue guns are pretty simple beasts: there’s an on/off switch, a heating element, and a source of current, be it battery or wired. You turn it on, and the heater starts warming up; eventually you can start extruding the thermoplastic sticks we call “hot glue”. Since there’s no temperature control, the longer you run the gun, the warmer it gets until it is inevitably hotter than you actually want– either burning you or oozing thermoplastic out the tip. [Mellow_Labs] was sick of that after a marathon hot-glue session, and decided to improve on his hot glue gun with PID tuning in the video embedded below.

PID tuning is probably a familiar concept to most of you, particularly those who have 3D printers, where it’s used in exactly the same way [Mellow_Labs] puts it to work in the hot glue gun. By varying the input (in this case the power to the heater) proportional both to the Parameter (in this case, temperature) as well as the Integral and Derivative of that value, you can have a much steadier control than more naive algorithms, like the simple “on/off” thermostat that leads to large temperature swings.

In this case [Mellow_Labs] is implementing the PID control using a thermistor that looks like it came from a 3D printer, and a MOSFET driven by an RP2040. Microcontroller gets its power via the hot glue gun’s battery fed through a buck converter. Since he has them, a small OLED screen displays temperature, which is set with a pair of push-buttons. Thus, one can set a temperature hot enough to melt the glue, but low enough to avoid oozing or third degree burns.

He does not share the code he’s running on the RP2040, but if you are inspired to replicate this project and don’t want to roll your own, there are plenty of example PID scripts out there, like the one in this lovely robot. No, PID isn’t reserved for thermostats– but if you are controlling heat, it’s not reserved for electric, either. Some intrepid soul put built a PID controller for a charcoal BBQ once. Continue reading “Tired Of Burnt Fingers? Try PID Tuning The Hot Glue Gun” →

PiStorm68K Offers Supercharged Retro Amiga Experience

January 6, 2026 by John Elliot V 8 Comments

[AmiCube] has announced their new PiStorm68K special edition MiniMig accelerator board. This board was developed to replace the 68000 CPU in a MiniMig — a recreation of the original Amiga chipset in an FPGA allowing a real genuine 68000 CPU to operate.

The PiStorm68K itself can host a real genuine 68000 CPU but it can also host various Raspberry Pi models which can do emulation of a 68000. So if you combine a PiStorm68K with a MiniMig you can, at your option, boot into an emulated environment with massively increased performance, or you can boot into an original environment, with its reliable and charming sluggishness.

In the introduction video below, [AmiCube] uses the SYSINFO utility software to compare the CPU speed when using emulation (1531 MIPS) versus the original (4.47 MIPS), where MIPS means Millions of Instructions Per Second. As you can see the 68000 emulated by the Raspberry Pi is way faster than the original. The Raspberry Pi also emulates a floating-point unit (FPU) which the original doesn’t include and a memory management unit (MMU) which isn’t used.

If you’re interested in old Amiga tech you might also like to read about Chip Swap Fixes A Dead Amiga 600 or The Many-Sprites Interpretation Of Amiga Mechanics.

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Linux Fu: Yet Another Shell Script Trick

January 6, 2026 by Al Williams 2 Comments

I’m going to go ahead and admit it: I really have too many tray icons. You know the ones. They sit on your taskbar, perhaps doing something in the background or, at least, giving you fingertip access to some service. You’d think that creating a custom tray icon would be hard, but on Linux, it can be surprisingly simple. Part of the reason is that the Freedesktop people created standards, so you don’t typically have to worry about how it works on KDE vs. GNOME or any of the other desktop environments. That’s a big win.

In fact, it is simple enough that you can even make your own tray icons with a lowly shell script. Well, of course, like most interesting shell scripts, you need some helper programs and, in this case, we’ll use YAD — which is “yet another dialog,” a derivative of Zenity. It’s a GTK program that may cause minor issues if you primarily use KDE, but they are nothing insurmountable.

The program is somewhat of a Swiss army knife. You can use it to make dialogs, file pickers, color selectors, printer dialogs, and even — in some versions — simple web browsers. We’ve seen plenty of tools to make pretty scripts, of course. However, the ability to quickly make good-looking taskbar icons is a big win compared to many other tools.

Docs

Depending on what you want to do, YAD will read things from a command line, a file, or standard input. There are dozens of options, and it is, honestly, fairly confusing. Luckily, [Ingemar Karlsson] wrote the Yad Guide, which is very digestible and full of examples.

Exactly what you need will depend on what you want to do. In my case, I want a tray icon that picks up the latest posts from my favorite website. You know. Hackaday?

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The Use Of Ultrasound To Take On Cancerous Tumors

January 6, 2026 by Maya Posch 30 Comments

As areas of uncontrolled cell growth, cancerous growth form a major problem for a multi-celled organism like us humans. Thus before they can begin to affect our long-term prospects of a continued existence, eradicating these cells-gone-wrong is essential. Unfortunately, doing so without affecting healthy cells significantly is tough. Treatments such as chemotherapy are correspondingly rough on the body, while radiation therapy is a lot more directed. Perhaps one of the more fascinating treatments involves ultrasound, with the IEEE Spectrum magazine recently covering one company providing histotripsy equipment.

Diagram showing how HIFU can be used to destroy tissue in the body. An acoustic lens is used to focus sound to a small point in the body. (Credit: James Ross McLaughlan, Wikimedia)

Ultrasound has found many applications in the medical field far beyond imaging, with therapeutic ultrasound by itself covering a variety of methods to perform actions within the body without breaking the skin. By using high-energy ultrasound, everything from kidney stones to fat cells and cancerous cells can be accurately targeted and destroyed. For liver tumors the application of so-called histotropsy has become quite common, allowing certain types of tumors to be ablated non-invasively after which the body can handle the clean-up.

Histotropsy is a form of high-intensify focused ultrasound (HIFU) that uses either continuous or pulsed waves to achieve the desired effect, with the HIFU transducer equipped with an acoustic lens to establish a focal point. In the case of histotripsy cavitation is induced at this focal point that ends up destroying the local tissue. Beyond liver tumors the expectation is that other tumors will soon be treated in a similar manner, which could be good news for especially solid tumors.

Along with new approaches like CAR T cell immunotherapy, the prospects for cancer becoming a very treatable set of diseases would seem to be brighter than ever.

How Advanced Autopilots Make Airplanes Safer When Humans Go AWOL

January 6, 2026 by Maya Posch 19 Comments

It’s a cliché in movies that whenever an airplane’s pilots are incapacitated, some distraught crew member queries the self-loading freight if any of them know how to fly a plane. For small airplanes we picture a hapless passenger taking over the controls so that a heroic traffic controller can talk them through the landing procedure and save the day.

Back in reality, there have been zero cases of large airliners being controlled by passengers in this fashion, while it has happened a few times in small craft, but with variable results. And in each of these cases, another person in the two- to six-seater aircraft was present to take over from the pilot, which may not always be the case.

To provide a more reliable backup, a range of automated systems have been proposed and implemented. Recently, the Garmin Emergency Autoland system got its first real use: the Beechcraft B200 Super King Air landed safely with two conscious pilots on board, but they let the Autoland do it’s thing due to the “complexity” of the situation.

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