Mysterious Files PH

Cooking food with fire is arguably the technology that propelled humans to become the dominant species on Earth. It’s pretty straightforward to achieve, just requiring a fuel source, a supply of oxygen from the air, and a way to initiate the reaction; then it self-sustains. You wouldn’t think there’s much to improve, but what about cooking with plasma? [Jay] from the plasma channel is no stranger here, and he thinks that there may be something in this idea, certainly enough to actually build something.

Now, let’s be straight with you, this isn’t a new concept, and you can buy a plasma-based cooking appliance right now. But they are all AC-powered devices. What if you want to go camping? [Jay] attempts (and succeeds) in building a portable, rechargeable 600W plasma cooking device that can actually cook food, but it was not all plain sailing.

The existing off-the-shelf ZVS driver modules available were a bit weak and unreliable, and the required flyback coils were hard to find with the right specs, so he needed to get down to work building custom parts. First off, the coils. Custom formers were resin-printed and machine-wound with 4000 turns of fine wire, and then resin-sealed into the former. [Jay] takes care to explain that it is crucial to get all the air out of the windings, or else local flashover breakdown will occur and wreck the coil in a short time. We reckon the resulting coils look amazing in their own right!

Next, the ZVS drivers on hand had low-quality capacitors (well, not enough capacitance anyway) and cheap driver transistors, so both were upgraded. The initial plan was to have four driver/coil pairs, each driving a single pair of electrodes, with a common ground ring connecting them all. It turns out this was a terrible idea: the drivers were not synchronised, so they were pulling on each other, causing catastrophic damage to the PCBs in a very short time. The solution was more complicated wiring, to give each coil secondary output a dedicated electrode pair, so there was no direct electrical connection between neighbouring coils and no coupling between them. A clever electrode arrangement meant that a pan would sit on top of a ring of electrodes, causing plasma discharges to jump directly to the pan, thereby concentrating localised heating there. We were wondering how this new direct connection (the pan is now a common connection!) didn’t also cause backfeeding and kill the ZVS drivers again, but it didn’t seem to happen.

Anyway, [Jay] demonstrates what is possibly the world’s first rechargeable, portable plasma cooker capable of making breakfast. Which we think is very important in its own right, however, we would like a plasma-based solution to making toast next, perhaps a plasma knife that cooks the bread as you slice it?

If this plasma cooking lark rings a bell, yes, we did touch upon this way back in 2017. And whilst not strictly plasma cooking, you can make an amazing microwave plasma in this ridiculously upgraded appliance. Definitely do not try that one at home.

We’ve all had those times when your electrical device of choice is running low on battery. Sometimes you even plan ahead and are also carrying a battery pack, but what happens when you’ve forgotten to charge the battery pack? This is the problem that [Arnov Sharma] addressed with the SolMate, a portable solar panel that keeps a battery bank topped up.

The SolMate is built around an efficient 2 W photovoltaic panel that’s not much bigger than a cellphone. This panel can supply 5 V at 400 mA on a sunny day. The solar output is more than enough to keep the internal 2000 mAh battery topped up and ready for use. Charging the Li-ion battery is handled by an IP5306 power management chip, which pulls double duty: it safely regulates charging while boosting the battery’s 3.7 V to the 5 V expected at the USB charge ports. Speaking of charge ports, the SolMate includes both a USB-A and a USB-C port, plus a switch to enable or disable the unit.

The case is all 3D printed, with some clever design choices. Offsetting the bulk of the battery and PCB storage area to one side lets the SolMate naturally cant toward the sun. Even the clip used to attach it to a backpack is printed.

Be sure to check out the other entries into our latest challenge!

It’s the evening before publication, and a pair of Hackaday writers convene to record the week’s podcast. This week Elliot Williams is joined by Jenny List, and it’s a bumper episode!

Of course, a bit of Hackaday news makes the cut, as it’s time to make an entry in the Green Powered Challenge. Then we make the first of a couple of sojourns into AI, as we talk about the Linux kernel stance on AI code. In short: if you submit AI code you’re responsible for its bugs. Meanwhile out of this world, we look forward to a time when astronauts breathe oxygen from moon dust.

There are hacks aplenty for your enjoyment, starting with far more than you ever thought it was possible to know about  sound-reactive LED strips. Then we have among others a Mac on an ESP32 forming the UI for a weather monitor, Doom on a toaster, and a fascinating look at screw threads for plastic.

In the longer reads we have our colleague [Tom Nardi] finding Chinese people’s personal data on hard drives he bought in an electronics store, and an attempt to look at what an LLM can do that might be useful. Grab your headphones, and join us!

Download your own Podcast!

Episode 365 Show Notes:

News:

• New Linux Kernel Rules Put The Onus On Humans For AI Tool Usage
• From Lunar Dust To Breathable Air
  • LEGO Bricks: Now Out Of This World
• The Hackaday Green Powered Challenge

What’s that Sound?

• Congrats to [Sean rules] for guessing the pencil sharpener!

Interesting Hacks of the Week:

• Audio Reactive LED Strips Are Hard
• ESP32 Weather Display Runs Macintosh System 3
• An Electric Jellyfish For Androids
  • [likeablob]’s GitHub repositories
• New Display For Old Multimeter
• They Weren’t Joking: Gentoo WAS Ported To GNU Hurd
• Skylab Under The Ocean
• Using Metal Screws In Plastic Parts
  • No Need For Inserts If You’re Prepared To Use Self-Tappers

Quick Hacks:

• Elliot’s Picks:
  • DOOM On A Fancy Smart Toaster
  • By Our Calculations, You’ll Love The Flapulator
  • Flattening The Exhaust Of A Laser Cutter To Save Space
• Jenny’s Picks:
  • MotoGP Rubber = Better Climbing?
  • Upgrading A MacBook Neo Using A 1 TB IPhone NAND Flash
  • A Mercury Rover Could Explore The Planet By Sticking To The Terminator

Can’t-Miss Articles:

• https://hackaday.com/2026/04/15/a-tale-of-cheap-hard-drives-and-expensive-lessons/
• AI For The Skeptics: Pick Your Reasons To Be Excited
• AI For The Skeptics: Attempting To Do Something Useful With It

Well, this might just be a Hackaday first. Certainly not the circuit sculpture part, nor the wearable aspect, but the glorious combination of the two. Behold [CMoz]’s Fashionably on Task: a Smart Bracelet for Forgetfulness. The name may be long, but the intent is concise: to showcase your top five must-dos for the day.

This lovely bracelet uses a tri-color e-paper display, and it’s WiFi enabled in order to receive input from the corresponding phone app. Although the cute pink ESP32-C3 is programmed in PlatformIO, the code will work with the Arduino IDE as well.

To get down to business, just power on the bracelet. If it can’t connect to the network you’ve hard-coded, it will broadcast it’s own access point. Connect with your phone to the custom web page, and Bob’s your uncle. From here, you can enter the tasks, change the colors around, mark tasks as complete, and remove tasks or reset recurring reminders.

The nifty part is that e-paper screen, since it will of course continue to display your list once powered down. Here’s the full code. Then you can deep-dive into the graph theory of circuit sculptures.

While it might seem quaint these days, we’ve met many makers and hackers who reach for a pen and a pad when learning something new or working their way through some technical problem. But even if you’re the type of person who thinks best when writing something out on paper, there’s still a good chance that you’ll eventually want to bring those notes and sketches into the digital realm. That’s where things can get a little tricky.

[Spencer Adams-Rand] recently wrote in with his clever solution for capturing written notes and pushing them into Notion, but the hardware design and digitization workflow is flexible enough that it could be adapted to your specific needs — especially since he was good enough to release all the files required to build your own version.

Whether they are hand-written notes, old photographs, or legal documents, digitization boils down to taking a high resolution digital photo of the object and running it through the appropriate software. But getting good and consistent photos is the key, especially when you’re working your way through a lot of pages. [Spencer] started out just snapping pictures with his phone, but quickly found the process was less than ideal.

His custom scanning station addresses that first part of the problem: getting consistent shots. The images are captured using a Raspberry Pi 5 with attached Camera Module 3, while the 3D printed structure of the device makes sure that the camera and integrated lighting system are always in the same position. All he needs to do is place his notepad inside the cavity, hit the button, and it produces a perfect shot of the page.

Using a dedicated digitizing station like this would already provide better results than trying to freehand it with your phone or camera, but [Spencer] took things quite a bit farther. The software side of the project puts a handy user interface on the 5 inch touch screen built into the top of the scanner, while also providing niceties like a REST API and integration with the OpenAI Vision API for optical character recognition (OCR).

Those with an aversion to AI could certainly swap this out for something open source like Tesseract, but [Spencer] notes that not only is OpenAI’s OCR better at reading his handwriting, it spits out structured markdown-like data that’s easier to parse. From there it goes into the Notion API, but again, this could be replaced with whatever you use to collect your digital thoughts.

A device like this would go a long way towards answering a question we posed to the community back in January about the best way to digitize your documents.

Information, it seems, flows at the speed of media. In the old days, information traveled with people on ships or horses, so if, say, a battle was won or lost, it could be months or even years before anyone back home knew what happened. While books and movable type let people store information, they still moved at the speed people moved. Before the telegraph, there were attempts to use things like semaphores to speed the flow of information,  but those were generally limited to line-of-sight operations. Carrier pigeons were handy, but don’t really move much faster than people.

The telegraph helped, but people didn’t have telegraph stations in their homes. At least not ordinary people. But radio was different. It didn’t take long for every home to have a radio, and while the means of broadcasting remained in the hands of a few, the message could go everywhere virtually instantly. This meant news could go from one side of the globe to the other in seconds. It also meant rumors, fads, and what we might think of today as memes could, too.

You might think that things “going viral” is a modern problem, but, in reality, media sensations have always been with us. All that changes is the number of them and their speed.

One of the earliest viral media sensations dealt with William Floyd Collins, an unfortunate man who was exploring caves during the Kentucky Cave Wars.

Background

Mammoth Cave in Kentucky had become a major tourist attraction. The accessible entrance to the cave was located on land owned by the Croghan family. The massive cave system had been made famous in the 19th century, and with the construction of a lock and dam nearby in 1906, Mammoth Cave became accessible to ordinary tourists.

However, the cave wasn’t completely under the Croghan land. There were also other caves that may or may not have been connected with Mammoth Cave. This led to fierce competition. The Croghan family suppressed information about exactly what land was over the cave. Meanwhile, other cave “owners” would intercept people heading for the cave, tell them that Mammoth Cave was closed, and “helpfully” direct them to another location.

By the 1920s, George Morrison blasted new entrances to the cave on non-Croghan land. There was fierce interest in finding new entrances to the cave or nearby caves to capture tourist money.

Back to Floyd

Floyd Collins found an entrance into what would become known as the “Great Crystal Cave” in 1917 and opened it to tourists in 1918. Unfortunately, the cave was hard to access, so it didn’t make much money.

Floyd had started entering caves in 1893 at the age of six. He discovered his first cave in 1910. But Great Crystal Cave was too far off the main road. He entered into a deal with three farmers who owned land closer to the main highway. If Floyd could find a suitable cave or, even better, an entrance to Mammoth Cave, he’d partner with them and create a mutually profitable tourist attraction.

Floyd found a hole in what would become known as Sand Cave. Some of the passages he had to move through were as tight as 9 inches, which, of course, would not be suitable for tourists, but they opened, apparently, into a large grotto. He was determined to expand the entrance to make the cave commercially viable.

In January of 1925, he was working in the cave when his gas lamp started to dim. He tried to leave, but while trying to move through a small passage, he knocked over his light, leaving him in total darkness.

In the dark, he put his foot against a seemingly stable wall and caused a shift that pinned his leg with a rock weighing nearly 30 pounds. He was also buried in gravel. At this point, he was 150 feet from the hole to the surface.

The Media

The next day, people noticed Floyd was missing, but no one would dare to follow him through the narrow passages. His younger brother finally got close enough to determine what happened. He was able to give Floyd food and water as plans for a rescue developed.

After four days in the cave, several people tried to pull Floyd out using a rope and a harness, but they only wound up injuring him. Meanwhile, the media had taken interest in the case, and the publicity drew hundreds of tourists and amateur spelunkers. Campfires and, possibly, the electric light that had been placed to give Floyd some light and warmth, melted ice inside the cave, creating puddles of water around the trapped man.

Two days after the failed rescue attempt, rain and the melting ice caused the cave passage to collapse, and the rescue team determined it was too dangerous to dig it back out after making an attempt to do so. They decided to dig straight down to reach Floyd.

Digging

Unfortunately, the cave drew air in so they decided they could not use mechanical diggers without risking suffocating Floyd. That meant humans would have to dig the 55-foot shaft to reach the victim. The initial estimate that 75 volunteers could dig the shaft in 30 hours proved optimistic, as conditions worsened and the hole grew deeper.

Someone disconnected the wires from the light bulb and connected them to an audio amplifier to detect signs of life from the victim. They believed the repetitive crackling noise meant he was breathing.

The light bulb went open on February 11th, twelve days after the incident started. Five days later, they reached his body. He had died and had been dead for several days.

You can find a well-done documentary from Remix Films in the video below. For a movie inspired by the event, check out the Billy Wilder film Ace in the Hole (1951) starring Kirk Douglas.

Viral

A newspaper reporter, William Miller, was on the scene and, being a small man, was able to actually help remove gravel from Floyd before the cave-in. His interview with the man from inside the cave won a Pulitzer Prize.

There was a time when this would have been only a sensational local story, but by the modern year of 1925, reports “went out on the wire” by telegraph and were picked up by newspapers worldwide. The nearest telegraph station was miles away, so two ham radio operators (9BRK and 9CHG) provided a link between the site, the newspaper, and the authorities.

The first broadcast radio station, KDKA, was only five years old, but stations provided news bulletins detailing the progress. Thanks to the media, crowds were reported to number in the tens of thousands. Eventually, the National Guard arrived to help control the crowds.

Vendors popped up to sell hamburgers and memorabilia like a macabre circus. As you can see in the video below, memorabilia about the event and Floyd Collins can be worth a pretty penny to collectors.

The whole thing became one of the three largest media events between World War I and World War II. The other two were Lindbergh’s transatlantic flight (1927) and the kidnapping of Lindbergh’s baby (1932). Oddly, Lindbergh was an acquaintance of Floyd’s and also flew news photos from the scene (although, reportedly, to the wrong newspaper).

While it wasn’t quite as big an event, Canada’s 1936 Moose River Gold Mine collapse was a similar situation and also received worldwide media attention. It has the distinction of being the first 24-hour radio coverage of a breaking news story in Canada.

Today

These days, sensational news stories pop up everywhere. It seems as if they hardly get started when they are displaced by another one. But we submit that “going viral” isn’t a modern phenomenon. Only the speed at which it happens. Even an 1835 newspaper was able to spur a viral hoax.

Featured image: “Mammoth Cave Saltpeter Mine” by [Bpluke01]

Although we have many types of networking equipment with many unique names, at their core they can usually be reduced to just a computer with some specific peripherals. This is especially the case for something like a router, a device found in just about any home these days. Certain consumer-grade routers may contain something special like a VDSL modem, but most of them just have a WAN Ethernet jack on one end and one or more LAN-facing Ethernet ports.

All further functionality is implemented in software, including any firewall, routing and DHCP features. What this means is that any old PC with at least two Ethernet ports or equivalent can be a router as long as you install the appropriate software.

In this article we’ll be taking a look at what consumer-level options there exist here today, ideally something so simple that the average home user could set it up with a bit of coaching.

When Routers Were Terrible

Although these days most people are probably happy to use whatever consumer router gets tossed their way by their ISP or purchased from any of the many electronics retailers, the era of home routers starting in the 90s was a rough one. Not only did many ISPs for a long time have strict rules against even thinking of installing any kind of connection-sharing router on the precious internet connection they so gracefully provided access to, the routers that were available even during the 2000s also weren’t particularly good.

Perhaps the most egregious issue that you’d run into as a somewhat internet-savvy user was that these units came with the tiniest amount of RAM and a routing table that would fill up within seconds if you so much as thought of doing anything naughty like downloading Linux ISOs with Bittorrent. Even more than the lightest internet use risked issues such as the router freezing up and requiring a reboot.

Being the nerdy type who’d hang out on various tech forums during that time, I instead opted to toss some ISA NICs into an old 486DX2-66 PC, put FreeSCO on a 1.44 MB floppy and used that instead. Even the 16 MB or so of EDO or FP RAM in that old system easily kept up with whatever internet traffic-related abuse I threw at it along with the rest of the family.

Later I’d also use Smoothwall on a trashed Pentium 166 system that I had salvaged from e-waste as a healthy upgrade. Yet over time as consumer routers stopped being terrible, I’d end up using those instead. That said, despite recent improvements there are still reasons today to put your own router together.

These reasons can vary from a simple increase in control, as well as peace of mind in an era where commercial consumer router firmware do not appear to get quite the quality assurance they should get. There is also the specter of repressive government policies, and of course less dramatic reasons such as just being into tinkering with networking gear.

Modern Options

Although we have moved on quite a few years from the 2000s, it’d be nice if we could still theoretically dig an ancient 486 PC out of a closet and use it, just to push back the minimum requirements as far as possible. Looking at the list of router and firewall distributions over at Wikipedia we can get a bit of an idea of what’s out there today. Naturally we’d like something that’s open source, recently updated and well-supported as we’ll be exposing it to the worst that the modern Internet has to offer.

Sadly, FreeSCO isn’t even the list, and based on the project’s website it doesn’t appear to have been updated since 2014. Similarly, Smoothwall’s free version (Express) doesn’t appear to be quite supported any more, with the commercial offering being promoted instead. A promising project is something like OPNsense, which is a FreeBSD-based distribution that does basically everything networking-related and then some. It’s also rather resource-heavy, demanding 4+ GB of RAM and so on, for features that the average home user is unlikely to use.

Ultimately only two projects really jump out: the first is the Linux Embedded Appliance Framework (LEAF), which feels like a spiritual successor to FreeSCO in targeting 486 or better hardware while running read-only off floppy discs or better.

The second project is the well-known OpenWrt, which doesn’t just provide alternative firmware images for commercial routers, but also for generic x86 and ARM hardware. This should tick all the aforementioned boxes, including the ability to run off an x86-compatible potato, while theoretically also providing driver support for just about any NIC and maybe even WNICs.

Amusingly, my current internet router is a Xiaomi device that runs OpenWrt with a custom web UI, so I’m already familiar with it in that sense. I also have no complaints about its stability, so this should be smooth sailing as a first try.

A quick sidenote here: although I did say that consumer-grade routers aren’t terrible any more today, this Xiaomi router replaced a horrid TP-Link Archer C80 with its tiny 4 MB Flash, incompatibility with OpenWrt and broken IPv6 support. Caveat emptor, as they say, for consumer-grade routers can absolutely still be terrible.

It’s Not Hoarding, I Swear

Like any self-respecting tech-enthusiast I happen to have a few drawers and boxes with relevant computer hardware, including a stash of industrial Intel Atom mini-ITX boards and some PCI Gbit NICs. Although I could have tossed this into a scruffy old case with a questionably-but-probably-fine PSU, I decided to get a new budget case and PSU, just to feel more confident about flipping on the power switch:

The mainboard is a 2009-era Intel Desktop Board D410PT, with two sticks of 1 GB DDR2 RAM. There’s just an onboard 10/100 Mbit Ethernet adapter in addition to the PCI 1 Gbit adapter, but this is good enough to test basic principles. Plus older Ethernet chips definitely ought to be supported.

With this whole kit built together, the OpenWrt Wiki entry on x86 installations was followed, with an Ext4-based non-EFI image written to a 512 MB microSD card. This card was inserted into the system with a USB adapter, though as the Wiki page makes clear there are many more ways to install OpenWrt, including on an internal (SATA/IDE/etc.) storage device.

Here the OpenWrt image selection process is definitely a bit more complicated than that for e.g. FreeSCO, as you have to know whether the system boots using a UEFI or traditional BIOS, as well as decide between the SquashFS and Ext4 root partition option. Even after looking at the pros and cons of both I’m still torn on which one is best.

There is also the issue of supported network cards, with the typical image supporting Intel and Realtek Ethernet chipsets. Having compatible NICs installed is even more important than back in the generic NE2000 days.

Sad Trombone

After firing up the newly built rig and briefly powering it down to replace the very much drained CMOS battery, I had hoped to see something promising on the connected screen. Yet other than the PXE boot attempts from both Ethernet cards before a sad ‘no bootable devices found’ error message nothing happened.

I did go through the BIOS to make sure that all ‘boot from USB’ options were enabled and tried multiple SD-card-to-USB adapters in multiple USB ports, but it would seem that either the provided OpenWrt image isn’t bootable or the Curse of Bootable USB Devices has struck again.

While I haven’t given up yet on DIY-ing an x86 router on older hardware in 2026 and still have to give LEAF a shot, I must say that compared to the FreeSCO method of just slapping that floppy into the FDD, running through the config and being done, things are a lot more complicated today. I’d definitely not trust the average person to run through these steps to set up their own consumer-grade router.

Perhaps for the LEAF version I’ll dig up a rig with FDD header on the mainboard and run it off a 1.44 MB floppy like in the good old days. Until then feel free to sound off in the comments about what obvious mistakes I have made with OpenWrt, how I should just use OPNsense on an old 19″ rackmounted Xeon server rig, or maybe your own experiences with FreeSCO, SmoothWall, OpenWrt, and/or LEAF on lovingly restored e-waste.

Featured image: “Ethernet Router” by [gratuit].