Analog Surround Sound Was Everywhere, But You Probably Didn’t Notice

October 28, 2025 by 15 Comments

These days, most of the media we consume is digital. We still watch movies and TV shows, but they’re all packaged in digital files that cram in many millions of pixels and as many audio channels as we could possibly desire.

Back in the day, though, engineering limitations meant that media on film or tape were limited to analog stereo audio at best. And yet, the masterminds at Dolby were able to create a surround sound format that could operate within those very limitations, turning two channels in to four. What started out as a cinematic format would bring surround sound to the home—all the way back in 1982!

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Mushrooms As Computer Memory

October 28, 2025 by 32 Comments

Fungi make up a massive, interconnected part of Earth’s ecosystems, yet they’re vastly underrepresented in research and public consciousness compared to plants and animals. That may change in the future though, as a group of researchers at The Ohio State University have found a way to use fungi as organic memristors — hinting at a possible future where fungal networks help power our computing devices.

A memristor is a passive electronic component whose resistance changes based on the voltage and current that has passed through it, which means it can effectively remember past electrical states even when power is removed. To create these circuit components with fungus, the researchers grew shiitake and button mushroom mycelium for these tests, dehydrated their samples for a number of days, and then attached electrodes to the samples. After misting them briefly to restore conductivity, the samples were exposed to various electrical wave forms at a range of voltages to determine how effective they were at performing the duties of a memristor. At one volt these systems were the most consistent, and they were even programmed to act like RAM where they achieved a frequency of almost 6 kHz and an accuracy of 90%.

In their paper, the research group notes a number of advantages to building fungal-based components like these, namely that they are much more environmentally friendly and don’t require the rare earth metals that typical circuit components do. They’re also easier to grow than other types of neural organoids, require less power, weigh less, and shiitake specifically is notable for its radiation resistance as well. Some work needs to be done to decrease the size required, and with time perhaps we’ll see more fungi-based electrical components like these.

Two colored plastic films are loosely tied over the entrances to two plastic containers.

Cooking Up Plastics In The Kitchen

October 28, 2025 by 3 Comments

The earliest useful plastics were made out of natural materials like cellulose and casein, but since the Bakelite revolution, their use has dwindled away and left them mostly as curiosities and children’s science experiments. Fortunately, though, the raw materials for bioplastics are readily available in most grocery stores, and as [Ben] from NightHawkInLight demonstrates, it’s still possible to find new uses for them.

His first recipe was for a clear gelatine thermoplastic, using honey as a plasticizer, which he formed into the clear packet around some instant noodles: simply throw the whole packet into hot water, and the plastic dissolves away. With some help from the home bioplastics investigator [Giestas], [Ben] next created a starch-based plastic out of starch, vinegar, and glycerine. Starch is a good infrared emitter in the atmospheric window, and researchers have made a starch-plastic aerogel that radiates enough heat to become cooler than its surroundings. Unfortunately, this requires freeze-drying, and while encouraging freezer burn in a normal freezer can have the same effect, it’ll take a few months to get a usable quantity of the material.

The other problem with starch-based plastics is their tendency to absorb water, at least when paired with plasticizers like glycerine or honey. Bioplastics based on alginate, however, are easy to make waterproof. A solution of sodium alginate, derived from seaweed, reacts with calcium ions to make a cross-linked waterproof film. Unfortunately, the film forms so quickly that it separates the solutions of calcium ions from the alginate, and the reaction stops. To get around this, [Ben] mixed a sodium alginate solution with powdered calcium carbonate, which is insoluble and therefore won’t react. To make the plastic set, he added glucono delta lactone, which slowly breaks down in water to release gluconic acid, which dissolves the calcium carbonate and lets the reaction proceed.

The soluble noodle package reminded us of a similar edible package, which included flavoring in the plastic. We’ve also seen alginate used to make conductive string, and rice used to make 3D printer filament. It’s worth some caution, though – not all biologically-derived plastics are healthier than synthetic materials.

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Remembering Better Mono Graphics

October 27, 2025 by 12 Comments

No matter what kind of computer or phone you are reading this on, it probably has a graphics system that would have been a powerful computer on its own back in the 1980s. When the IBM PC came out, you had two choices: the CGA card if you wanted color graphics, or the MDA if you wanted text. Today, you might think: no contest, we want color. But the MDA was cheaper and had significantly higher resolution, which was easier to read. But as free markets do, companies see gaps and they fill them. That’s how we got the Hercules card, which supported high-resolution monochrome text but also provided a graphics mode. [The 8-bit Guy] has a look at these old cards and how they were different from their peers.

Actually, the original MDA card could do eight colors, but no one knew because there weren’t any monitors it could work with, and it was a secret. The CGA resolution was a whopping 640×200, while the MDA was slightly better at 720×350. If you did the Hercules card, you got the same 720×350 MDA resolution, but also a 720×348 graphics mode. Besides that, you could keep your monitor (don’t forget that, in those days, monitors typically required a specific input and were costly).

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Making A Virtual Machine Look Like Real Hardware To Malware

October 27, 2025 by 35 Comments

Running suspicious software in a virtual machine seems like a basic precaution to figure out whether said software contains naughty code. Unfortunately it’s generally rather easy to detect whether or not one’s software runs inside a VM, with [bRootForce] going through a list of ways that a VirtualBox VM can be detected from inside the guest OS. While there are a range of obvious naming issues, such as the occurrence of the word ‘VirtualBox’ everywhere, there many more subtle ways too.

Demonstrated is the PoC ‘malware’ application called Al-Khaser, which can be used to verify one’s anti-malware systems, such as when trying to unleash a debugger on a piece of malware, run it inside a VM, along with many more uses. Among its anti-virtualization features are specific registry key names and values, file system artefacts, directory names, MAC addresses, virtual devices, etc.

In order to squeeze by those checks, [bRootForce] created the vbox_stealth shell script for Bash-blessed systems in order to use the VirtualBox Manager for the renaming of hardware identifier, along with the VBoxCloak project’s PowerShell script that’s used inside a Windows VirtualBox guest instance to rename registry keys, kill VirtualBox-specific processes, and delete VirtualBox-specific files.

Theoretically this should make it much harder for any malware to detect that it’s not running inside Windows on real hardware, but as always there are more subtle ways that are even harder to disguise.

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Building A Hydraulic Gear Pump Isn’t So Easy

October 27, 2025 by 8 Comments
The gear pump prototype in action. (Credit: Artisan Makes, YouTube)
The gear pump prototype in action. (Credit: Artisan Makes, YouTube)

Hydraulic gear pumps are deceptively simple: just two gears rotating together, forcing the hydraulic oil from one side to the other where the teeth don’t meet, and thus providing the ability to pressurize said oil to make hydraulic cylinders, final drives, etc. do their thing. As with most machining projects like this, the devil is absolutely in the details, particularly in the tolerances. This is the crash course that the [Artisan Makes] channel on YouTube is currently going through.

In this part one of a series on a DIY gear pump, scrap aluminium is used for the housing, along with 1045 medium carbon steel for the gears and W1A high carbon steel for bearings and other wear surfaces. Since at least one of the gears needs to be driven, a lip seal rated for 10 bar is used to provide a path for the shaft. As noted in the video, this is supposed to be a learning experience, ergo it’s a simplified design that merely targets being functional as a gear pump.

With the basic design figured out, the parts were created on the lathe and mill, followed by assembly. Most of the controversy is about the tolerances within the housing, as any leakage will reduce the efficiency. This means the spacing between the gears and housing, space between the gears and bearings, as well as that provided by the gasket that seals the housing base and top. This is where the comment section somewhat explodes with criticism and advice.

As can be seen in the demonstration with a better gasket, there is absolutely flow when driven at 1200 RPM, but also clearly severe leakage as evidenced by said flow not moving quite as fast as it should. We’re looking forward to the next part, in which addressing these tolerances is tackled, with hopefully a much more performant gear pump resulting.

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The Supercon 2025 Badge Is Built To Be Customized

October 27, 2025 by 9 Comments

For anyone who’s joined us for previous years, you’ll know that badge hacking and modification are core to the Hackaday Supercon experience. While you’re of course free to leave the badge completely stock, we encourage attendees to tear it apart, learn how it works, and (hopefully) rebuild it into something unique. There are even prizes for the best hacks.

As such, every decision about the badge’s hardware and software is made with hackability in mind. It’s why we always try to add an expansion port to the badge and, in recent years, have leaned into MicroPython to make it easier for attendees to modify the code.

But one thing that’s been largely missing in previous badges is aesthetic customization. Sure, you could strip out the firmware and write something entirely new, or hang some oddball peripheral off the side of the thing, but ultimately it still looked like the badge we gave you at the door. That’s because, at the end of the day, the badges are just PCBs. Short of designing your own enclosure (which has certainly been done), every badge looks the same. That is, until now.

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