Converting A Sprinkler System To DC

August 22, 2025 by 14 Comments

Famously, Nikola Tesla won the War of the Currents in the early days of electrification because his AC system could use transformers to minimize losses for long distance circuits. That was well before the invention of the transistor, though, and there are a lot of systems that still use AC now as a result of electricity’s history that we might otherwise want to run on DC in our modern world. Sprinkler systems are one of these things, commonly using a 24V AC system, but [Vinthewrench] has done some work to convert over to a more flexible 24 VDC system instead.

The main components of these systems that are set up for AC are solenoids which activate various sets of sprinklers. But these solenoids can take DC and still work, so no major hardware changes are needed. It’s not quite as simple as changing power supplies, though. The solenoids will overheat if they’re fully powered on a DC circuit, so [Vinthewrench] did a significant amount of testing to figure out exactly how much power they need to stay engaged. Once the math was done, he uses a DRV103 to send PWM signals to the solenoids, which is set up to allow more current to pull in the solenoids and then a lower holding current once they are activated.

With a DC power supply like this, it makes it much easier to have his sprinkler system run on a solar powered system as well as use a battery backup without needing something like an inverter. And thanks to the DRV103 the conversion is not physically difficult; ensuring that the solenoids don’t overheat is the major concern here. Another great reason to convert to a DIY sprinkler controller is removing your lawn care routine from an unnecessary cloud-based service.

This Week In Security: Anime Catgirls, Illegal AdBlock, And Disputed Research

August 22, 2025 by 28 Comments

You may have noticed the Anime Catgirls when trying to get to the Linux Kernel’s mailing list, or one of any number of other sites associated with Open Source projects. [Tavis Ormandy] had this question, too, and even wrote about it. So, what’s the deal with the catgirls?

The project is Anubis, a “Web AI Firewall Utility”. The intent is to block AI scrapers, as Anubis “weighs the soul” of incoming connections, and blocks the bots you don’t want. Anubis uses the user agent string and other indicators to determine what an incoming connection is. But the most obvious check is the in-browser hashing. Anubis puts a challenge string in the HTTP response header, and JavaScript running in the browser calculates a second string to append this challenge. The goal is to set the first few bytes of the SHA-256 hash of this combined string to 0.

[Tavis] makes a compelling case that this hashing is security theatre — It makes things appear more secure, but doesn’t actually improve the situation. It’s only fair to point out that his observation comes from annoyance, as his preferred method of accessing the Linux kernel git repository and mailing list are now blocked by Anubis. But the economics of compute costs clearly demonstrate that this SHA-256 hashing approach will only be effective so long as AI companies don’t add the 25 lines of C it took him to calculate the challenge. The Anubis hashing challenge is literally security by obscurity.

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RepRapMicron Promises Micro-fabrication For Desktops With New Prototype

August 22, 2025 by 15 Comments

3D printing has transformed how hobbyists fabricate things, but what additional doors would open if we could go even smaller? The µRepRap (RepRapMicron) project aims to bring fabrication at the micron and sub-micron scale to hobbyists the same way RepRap strove to make 3D printing accessible. New developments by [Vik Olliver] show a promising way forward, and also highlight the many challenges of going so small.

New Maus prototype is modular, setting the stage for repeatable and reliable 3D printing at the micro scale.

How exactly would a 3D printer do micro-fabrication? Not by squirting plastic from a nozzle, but by using a vanishingly tiny needle-like effector (which can be made at any workbench via electrochemical erosion) to pick up a miniscule amount of resin one dab a time, curing it with UV after depositing it like a brush deposits a dot of ink.

By doing so repeatedly and in a structured way, one can 3D print at a micro scale one “pixel” (or voxel, more accurately) at a time. You can see how small they’re talking in the image in the header above. It shows a RepRapMicron tip (left) next to a 24 gauge hypodermic needle (right) which is just over half a millimeter in diameter.

Moving precisely and accurately at such a small scale also requires something new, and that is where flexures come in. Where other 3D printers use stepper motors and rails and belts, RepRapMicron leverages work done by the OpenFlexure project to achieve high-precision mechanical positioning without the need for fancy materials or mechanisms. We’ve actually seen this part in action, when [Vik Olliver] amazed us by scribing a 2D micron-scale Jolly Wrencher 1.5 mm x 1.5 mm in size, also visible in the header image above.

Using a tiny needle to deposit dabs of UV resin provides the platform with a way to 3D print, but there are still plenty of unique problems to be solved. How does one observe such a small process, or the finished print? How does one handle such a tiny object, or free it from the build platform without damaging it? The RepRapMicron project has solutions lined up for each of these and more, so there’s a lot of discovery waiting to be done. Got ideas of your own? The project welcomes collaboration. If you’d like to watch the latest developments as they happen, keep an eye on the Github repository and the blog.

Quieting That Radio

August 22, 2025 by 22 Comments

If you are casually listening to the radio, you probably tune into a local station and with modern receivers and FM modulation, the sound quality is good. But if you are trying to listen to distant or low-powered station, there’s a lot of competition. Our modern world is awash in a soup of electronic interference. [Electronics Unmessed] tells — and shows — us how much noise can show up on a SDR setup and what simple things you can do to improve it, sometimes tremendously.

According to the video, the main culprit in these cases is the RF ground path. If you have a single antenna wire, there still has to be a ground path somewhere and that may be through the power line or through, for example, a USB cable, the host computer, and its power supply. Unsurprisingly, the computer is full of RF noise which then gets into your receiver.

Adding a counterpoise makes a marked difference. A low inductance ground connection can also help. The counterpoise, of course, won’t be perfect, so to further turn down the noise, ferrite cores go around wires to block them from being ground paths for RF.

The common cores you see are encased in plastic and allow you to snap them on. However, using a bare core and winding through it multiple times can provide better results. Again, thanks to the SDR’s display, you can see the difference this makes in his setup.

None of this is new information, of course. But the explanation is clear, and being able to see the results in a spectrum display is quite enlightening. Those cores essentially turn your wire into a choke. People think that grounding is simple, but it is anything but.

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Now That Commodore Is Back, Could Amiga Be Next?

August 21, 2025 by 54 Comments

Now that Commodore has arisen from the depths of obscurity like Cthulhu awoken from R’lyeh, the question on every shoggoth’s squamose lips is this: “Will there be a new Commodore Amiga?”  The New Commodore is reportedly interested, but as [The Retro Shack] reports in the video embedded below, it might be some time before the stars align.

He follows the tortured history of the Amiga brand from its origins with Hi-Toro, the Commodore acquisition and subsequent Atari lawsuit, and the post-Commodore afterlife of the Amiga trademark. Yes, Amiga had a life after Commodore, and that’s the tl;dr here: Commodore might be back, but it does not own the Amiga IP.

If you’re wondering who does, you’re not the only one. Cloanto now claims the name and most of Amiga’s IP, though it remains at loggerheads with Hyperion, the distributors of AmigaOS 4. If you haven’t heard of them, Cloanto is not an elder god, but in fact the group behind Amiga Forever. They have been great stewards of the Amiga heritage over the decades. Any “new” Amiga is going to need the people at Cloanto on board, one way or another. That doesn’t mean it’s impossible– the new Commodore might be able to seduce Cloanto into a merger, or even just a licensing agreement to use the name on reproduction or new hardware.

While a replica C=64 was a no-brainer for the revived Commodore brand, it’s not quite so clear what they should do with the Amiga name. An FPGA reproduction of the popular A500 or A1200? Would anyone want newly-made 68000-based machines, or to follow Hyperion and MorphOS to now-outdated generations of PowerPC? All of these have been proposed and argued over for years.

We’d love to see something fully new that captures the spirit of the bouncing ball, but it’s hard to imagine bottling magic like that in the twenty-first century. For now, Amiga lies dreaming– but that is not dead which can eternally lie, and we hold out hope this Great Old One can return when the stars are right.

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Replicating The World’s Oldest Stringed Instrument

August 21, 2025 by 10 Comments

Posts on Hackaday sometimes trend a little bit retro, but rarely do we cover hacks that reach back into the Bronze Age. Still, when musician [Peter Pringle] put out a video detailing how he replicated an ancient Sumerian instrument, we couldn’t wait to dig in.

The instrument in question is the “Golden Lyre of Ur”, and it was buried at the Royal Cemetery of Ur with a passel of other grave goods (including a Silver Lyre) something around 4400 to 4500 years ago. For those not in the know, Ur was an early Sumerian city in the part of Mesopotamia became modern-day Iraq. A lyre is a type of plucked stringed instrument, similar to a harp.

That anything of the instrument remains after literal millennia buried under the Mesopotamian sand is thanks to the

This representation was unearthed in the same dig as the remains of the Golden Lyre and its silver sister.

extensive ornamentation on the original lyre– the gut strings and wooden body might have rotted away, but the precious stones and metals adorning the lyre preserved the outline of the instrument until it was excavated in 1922. Reconstruction was also greatly aided by contemporary mosaics and pottery showing similar lyres.

For particular interest are the tuning pegs, which required that artistic inspiration to recreate– the original archeological dig did not find any evidence of the tuning mechanism. [Peter] spends some time justifying his reconstruction, using both practical engineering concerns (the need for tension to get good sound) and the pictographic evidence. The wide “buzzing” bridge matches the pictographic evidence as well, and gives the lyre a distinct, almost otherworldly sound to Western ears. [Peter]’s reconstruction sounds good, though we have no way of knowing if it matches what you’d have heard in the royal halls of Ur all those dusty centuries ago. (Skip to 17:38 in the video below if you just want to hear it in action.)

The closest thing to this ancient, man-sized lyre we’ve seen on Hackaday before might be one of the various laser harp projects we’ve featured over the years. If you squint a little, you can see the distant echo of the Golden Lyre of Ur in at least some of them. We also can’t help but note that the buzzing bridge gives the Sumerian lyre a certain droning quality not entirely unlike a hurdy-gurdy, because we apparently can’t have a musical post without mentioning the hurdy-gurdy.

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Close up of a DIY minimalist EDC multitool, a penny, and a paperclip

This Pocket Multitool Weighs Less Than A Penny

August 21, 2025 by 26 Comments

A multitool that weighs less than a penny? Yes, it exists. This video by [ToolTechGeek] shows his titanium flat-cut design tipping the scales at only 1.9 grams—lighter than the 2.5-gram copper penny jingling in your pocket. His reasoning: where most everyday carry (EDC) tools are bulky, overpriced, or simply too much, this hack flips the equation: reduce it to the absolute minimum, yet keep it useful.

You might have seen this before. This second attempt is done by laser-cutting titanium instead of stainless steel. Thinner, tougher, and rust-proof, titanium slashes the weight dramatically, while still keeping edges functional without sharpening. Despite the size, this tool manages to pack in a Phillips and flathead screwdriver, a makeshift saw, a paint-lid opener, a wire bender (yes, tested on a paperclip), and even a 1/4″ wrench doubling as a bit driver. High-torque screwdriving by using the long edges is a clever exploit, and yes—it scrapes wood, snaps zip ties, and even forces a bottle cap open, albeit a bit roughly.

It’s not about replacing your Leatherman; it’s about carrying something instead of nothing. Ultra-minimalist, featherlight, pocket-slip friendly—bet you can’t find a reason not to just have it in your pocket.

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