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.

There were also questions from viewers about why he opted to rectify the AC power from the generator and use DC transmission to the nearest farm building. The main reason is efficiency, as DC transmission lines lack the skin effect losses. The other is that the grid-tie inverter that he plans to use needs DC input anyway. Not having to deal with AC transmission issues like losses and reactive power shenanigans is a major plus here.

Once the three new generator versions are being tested it will be interesting to see how they perform. One thing with the Kaplan-style turbine is that too fast RPM induces cavitation, which will erode the propeller pretty quickly. Generally car alternators require a pretty fast RPM, so that may not work out too well. There is also the question of the DC voltage generated, as for DC transmission you want to have as high a voltage as possible to reduce the current.

The purpose-built generator he purchased tops out at 48V, which is quite low. The goal is to have at least 230 VAC before rectification, so a step-up transformer may be needed. Unfortunately three-phase transformers are pretty pricy again, making the rewound alternator seem less crazy. The wild card here is perhaps whether the EBay-purchased generator is a diamond in the rough and works out of the box as hoped.

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hackaday.com/2026/01/06/the-ma…

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.

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hackaday.com/2026/01/06/tired-…

[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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hackaday.com/2026/01/06/pistor…

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?

The Web Connection

YAD can render HTML using WebKit. However, I ran into immediate problems. The version in the repos for the Linux I use was too old to include the HTML option. I found a supposedly statically linked version, but it was missing dependencies. Even after I fixed that, the program still reported errors related to the NVIDIA OpenGL stack.

I quickly abandoned the idea of using a web browser. I turned to two other YAD features. First, the basic dialog can hold text and, in most cases, renders quasi-HTML because it uses the Pango library. However, there is also a text-info dialog built in. Unlike most other YAD features, the text-info dialog reads its input from standard input. However, it doesn’t render markup.

In the end, I decided to try them both. Why not? It is simple enough. But first, I needed a tray icon.

The Tray

YAD can provide a “notification,” which is what it calls a tray icon. You can specify an icon, some text, and a right-click context menu. In addition, it can react when someone clicks on the icon.
Can you find the tray icon we’re talking about?
I decided to write a script with multiple personalities. If you run it with no arguments, it sets up the tray icon. If you pass anything to it, it will show a dialog with the latest Hackaday articles from the RSS feed. I wanted to make those links clickable, and that turned out to be a bit of a wrinkle. Both versions will do the job, but they each need a different approach, as you will see.

Here’s the tray code:

yad --notification --image="$0.icon.png" --text="Hackaday Now" \
--menu="Quit!quit!gtk-quit" --command="$0 show" --no-middle

You can probably guess at most of this without the manual. The image is stored in a file with the same name as the script, but with .icon.png at the end. That’s the icon in the tray. The simple menu provides an option to exit the program. If you click the icon, it calls the same script again, but with the “show” argument. The script doesn’t care what the argument is, but maybe one day it will.

So that part of the project was extremely simple. The next job is making the dialog appear.

Text Info

Grabbing the RSS feed with wget is trivial. You could use grep, sed, and bash pattern replacement to extract the titles and URLs, but I opted for awk and a brute-force parsing approach.
This works, but the URLs are long and not terribly attractive. The list is scrollable, and there are more links below the visible ones.
The standard output of awk pipes into YAD, but you can’t readily apply formatting or hyperlinks. You can use formatting in regular dialog text, which will appear before the other output. That’s where the yellow “Hackaday Today!” title in the adjacent screenshot gets set. In addition, you can automatically detect URLs and make them clickable using the --show-uri option.

Here’s the relevant command:

yad --text-info \
--text "<span foreground='$TITLECOLOR'><b><big><big>Hackaday Today!</big></big></b></span>" \
--show-uri --window-icon="$0.icon.png" \
--uri-color=$LINKCOLOR --width=$WIDTH --height=$HEIGHT \
--Title "Hackaday Posts" --button="Close!gtk-ok" \
--buttons-layout=center --escape-ok 2>/dev/null

You’ll notice that the –text option does take Pango formatting and the --show-uri option makes the links clickable. By default, dialogs have an Open and Cancel button, but I forced this one to have a single close button, accept escape, and I wanted the button centered.

As you can see in the screenshot, the result isn’t bad, but it does require having the title followed by a long URL that you can click on and that’s a little ugly.

Stock Dialog

Using a standard dialog instead of text-info allows better formatting.
Since the –text option works with any dialog and handles formatting, I decided to try that. The awk code was nearly the same, except for the output formatting. In addition, the output now needs to go on the command line instead of through a pipe.

This does make the script a bit more unwieldy. The awk script sets a variable, since jamming the command into the already busy YAD command line would make the script more complicated to read and work with.

The YAD command is still simple, though:

yad \
--text="$DATA" \
--window-icon="$0.icon.png" \
--width=$WIDTH --height=$HEIGHT \
--Title "Hackaday Posts" --button="Close!gtk-ok" \
--buttons-layout=center --escape-ok

The DATA variable has the formatted output text. The result looks better, as you can see in the screenshot. In either version, if you click an underlined link, your default browser should open the relevant post.

Other Choices

If you want to install either script, you can get it from GitHub. Of course, you could do this in Python or any other conventional language. There are also programs for “minimizing” another program to the tray, like AllTray or KDocker, although some of these may only work with X11 and not Wayland.

It would have been nice to have an integrated browser, although, thanks again to FreeDesktop, it is simple enough to open a URL and launch the system’s default browser.

Prefer your Hackaday feed on the command line? Check out the comments for this post. Meanwhile, send us a tip (you know, a link to your project, not a gratuity) and maybe you’ll see your own project show up on the feed.

hackaday.com/2026/01/06/linux-…

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.

hackaday.com/2026/01/06/the-us…

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.

Human In The Loop

Throughout the history of aviation, a human pilot has been a crucial component for the longest time for fairly obvious reasons, such as not flying past the destination airport or casually into terrain or rough weather. This changed a few decades ago with the advent of more advanced sensors, fast computing systems and landing assistance systems such as the ILS radio navigation system. It’s now become easier than ever to automate things like take-off and landing, which are generally considered to be the hardest part of any flight.

Meanwhile, the use of an autopilot of some description has become indispensable since the first long-distance flights became a thing by around the 1930s. This was followed by a surge in long-distance aviation and precise bombing runs during World War II, which in turn resulted in a massive boost in R&D on airplane automation.
A USAF C-54 Skymaster. (Credit: US Air Force)
While the the early gyroscopic autopilots provided basic controls that kept the airplane level and roughly on course, the push remained to increase the level of automation. This resulted in the first fully automatic take-off, flight and landing being performed on September 22, 1947 involving a USAF C-54 Skymaster. As the military version of the venerable DC-4 commercial airplane its main adaptations included extended fuel capacity, which allowed it to safely perform this autonomous flight from Newfoundland to the UK.

In the absence of GNSS satellites, two ships were located along the flight path to relay bearings to the airplane’s board computer via radio communication. As the C-54 approached the airfield at Brise Norton, a radio beacon provided the glide slope and other information necessary for a safe landing. The fact that this feat was performed just over twenty-eight years after the non-stop Atlantic crossing of Alcock and Brown in their Vickers Vimy airplane shows just how fast technology progressed at the time.

Nearly eighty years later, it bears asking the question why we still need human pilots, especially in this age of GNSS navigation, machine vision, and ILS beacons at any decently sized airfield. The other question that comes to mind is why we accept that airplanes effectively fall out of the sky the moment that they run out of functioning human pilots to push buttons, twist dials, and fiddle with sticks.

State of the Art

In the world of aviation, increased automation has become the norm, with Airbus in particular taking the lead. This means that Airbus has also taken the lead in spectacular automation-related mishaps: Flight 296Q in 1988 and Air France Flight 447 in 2009. While some have blamed the 296Q accident on the automation interfering with the pilot’s attempt to increase thrust for a go-around, the official explanation is that the pilots simply failed to notice that they were flying too low and thus tried to blame the automation.
The Helios Airways 737-300, three days before it would become a ghost flight. (Credit: Mila Daniel)
For the AF447 crash the cause was less ambiguous, even if took a few years to recover the flight recorders from the seafloor. Based on the available evidence it was clear by then that the automation had functioned as designed, with the autopilot disengaging at some point due to the unheated pitot tubes freezing up, resulting in inconsistent airspeed readings. Suddenly handed the reins, the pilots took over and reacted incorrectly to the airspeed information, stalled the plane, and crashed into the ocean.

One could perhaps say that AF447 shows that there ought to be either more automation, or better pilot training so that the human element can fly an airplane unassisted by an autopilot. When we then consider the tragic case of Helios Airways Flight 522, the ‘ghost flight’ that flew on autopilot with no conscious souls on board due to hypoxia, we can imagine a dead-man switch that auto-lands the airplane instead of leaving onlookers powerless to do anything but watch the airplane run out of fuel and crash.

Be Reasonable

Although there are still a significant number of people who would not dare to step a foot on an airliner that doesn’t have at least two full-blooded, breathing human pilots on board, there is definitely a solid case to be made for emergency landing systems to become a feature on airplanes, starting small. Much like the Cirrus Airframe Parachute System (CAPS) – a whole-airplane parachute system that has saved many lives as well as airframes – the Garmin Autoland feature targets smaller airplanes.
The Garmin Autoland system communicates with ATC and nearby traffic and lands unassisted. (Credit: Garmin)
After a recent successful test with a HondaJet, this recent unscheduled event with the Beechcraft B200 Super King Air twin-prop airplane turned out to be effectively another test. As the two pilots in this airplane were flying between airports for a repositioning flight, the cabin suddenly lost pressurization. Although both pilots were able to don their oxygen masks, the Autoland system engaged due to the dangerous cabin conditions. They then did not disengage the system as they didn’t know the full extent of the situation.

This effectively kept both pilots ready to take full control of the airplane should the need have arisen to interfere, but with the automated system making a textbook descent, approach and landing, it’s clear that even if their airplane had turned into another ghost flight, they would have woken up groggy but whole on the airstrip, surrounded by emergency personnel.

Considering how many small airplanes fly each year in the US alone, systems like CAPS and Autoland stand to save many lives both in the air and on the ground the coming years. Combine this with increased ATC automation at towers and elsewhere such as the FAA’s STARS and Saab’s I-ATS, and a picture begins to form of increased automation that takes the human element out of the loop as much as possible.

Although we’re still a long way off from the world imagined in 1947 where ‘electronic brains’ would unerringly fly all airplanes and more for us, it’s clear that we are moving in that direction, with such technology even within the reach of the average owner of an airplane of some description.

hackaday.com/2026/01/06/how-ad…

Besides being a fun way to pass time, video gaming is a surprisingly affordable hobby per unit time. A console or budget PC might only cost a few hundred dollars, and modern games like Hollowknight: Silksong can provide 40-60 hours of experience for only around $20 USD. This value proposition wasn’t really there in the 80s, where arcade cabinets like Gauntlet might have cost an inflation-adjusted $8 per hour in quarters. This paradigm shift is great for gamers, but hasn’t been great for arcade owners. [PrintAndPanic] wanted to bring some of that old coin munching vibe into console gaming, and so added a credit system to Super Mario 64.

The project is a fork of a decompilation of Super Mario 64, which converts the original machine code into a human-friendly format so bugs can be fixed and other modern features added. With the code available, essentially anyone can add features into the game that weren’t there already. In this case, [PrintAndPanic] is using a Raspberry Pi connected to a coin slot, so when coins are put into the game like an old arcade machine, the Raspberry Pi can tell the modified version of Super Mario 64 to add credits. These credits allow the player to run and jump, and when the credits run out Mario becomes extremely limited and barely able to outrun even the slowest Bombombs and Goombas.

With some debugging out of the way and the custom game working, [PrintAndPanic] built a custom enclosure for the game and the coin slot to turn it into a more self-contained arcade-style machine. The modified code for this project is available on the project’s GitHub page for those who want to play a tedious version of a favorite video game that costs more money than it should.

There are plenty of other modifications for this classic as well, most of which involve improving the game instead of adding a modern microtransaction-based system.

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hackaday.com/2026/01/06/super-…