Create Aerated Concrete Using Xanthan Gum And Dishwashing Liquid

December 28, 2025 by 2 Comments

To make aerated concrete, add a foam-forming agent and stir in a significant amount of air. This serves to make the concrete significantly lighter, better insulating, and more resilient to fire. Making it can however be a bit of an issue, often requiring ingredients that aren’t purchased at the average DIY store. This is where [NightHawkInLight]’s method seems rather promising, requiring effectively only xanthan gum and dishwashing detergent.

For the small-scale demonstration, 15 grams of the thickening agent xanthan gum is mixed with enough alcohol to create a slurry. To this 60 mL of the detergent and 1 liter of water is added and mixed until the xanthan gum has absorbed all the moisture, which takes about 5-10 minutes. This mixture is then added to Portland cement with two parts cement to one part xanthan gum/detergent mixture and mixed for a while.

Of importance here is that this mixture will keep expanding in volume while mixing, so you have to have to keep an eye on the amount of air relative to concrete, as this will determine the strength and other properties of the final aerated concrete. If you continue past a certain point you will even create open-celled aerated concrete that’s completely porous, so you have to know what kind of concrete you want before you start mixing up a big batch.

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Cheetah 3d printer mobo

Cheetah MX4 Mini: A Pint-Sized 3D Printer Controller

December 28, 2025 by 8 Comments

There’s a seemingly unending list of modifications or upgrades you can make to a 3D printer. Most revolve around the mechanical side of things, many are simple prints or small add-ons. This upgrade is no small task: this 17-year-old hacker [Kai] took on designing and building his own 3D printer control motherboard, the Cheetah MX4 Mini.

He started the build by picking out the MCU to control everything. For that, he settled on the STM32H743, a fast chip with tons of support for all the protocols he could ask for, even as he was still nailing down the exact features to implement. For stepper drivers, [Kai] went with four TMC stepstick slots for silent motor control. There are provisions for sensorless homing and endstops, support for parallel and serial displays, and both USB-C and microSD card slots for receiving G-code. It can drive up to three fans as well as two high-amperage loads, such as for the heated bed.

All these features are packed into a board roughly the size of a drink coaster. Thanks to the STM32H743, the Cheetah MX4 Mini supports both Marlin and Klipper firmware, a smart choice that lets [Kai] leverage the massive amount of work that’s already gone into those projects.

One of the things that stood out about this project is the lengths to which [Kai] went to document what he did. Check out the day-by-day breakdown of the 86 hours that went into this build; reading through it is a fantastic learning aid for others. Thanks [JohnU] for sending in this tip! It’s great to see such an ambitious project not only taken on and accomplished, but documented along the way for others to learn from. This is a fantastic addition to the other 3D printer controllers we’ve seen.

Cloudflare’s Outages And Why Cool Kids Test On Prod

December 28, 2025 by 9 Comments

Every system administrator worth their salt knows that the right way to coax changes to network infrastructure onto a production network is to first validate it on a Staging network: a replica of the Production (Prod) network. Meanwhile all the developers who are working on upcoming changes are safely kept in their own padded safety rooms in the form of Test, Dev and similar, where Test tends to be the pre-staging phase and Dev is for new-and-breaking changes. This is what anyone should use, and yet Cloudflare apparently deems itself too cool for such a rational, time-tested approach based on their latest outage.

In their post-mortem on the December 5th outage, they describe how they started doing a roll-out of a change to React Server Components (RSC), to allow for a 1 MB buffer to be used as part of addressing the critical CVE-2025-55182 in RSC. During this roll-out on Prod, it was discovered that a testing tool didn’t support the increased buffer size and it was decided to globally disable it, bypassing the gradual roll-out mechanism.

This follows on the recent implosion at Cloudflare when their brand-new, Rust-based FL2 proxy keeled over when it encountered a corrupted input file. This time, disabling the testing tool created a condition in the original Lua-based FL1 where a NIL value was encountered, after which requests through this proxy began to fail with HTTP 500 errors.  The one saving grace here is that the issue was detected and corrected fairly quickly, unlike when the FL2 proxy fell over due to another issue elsewhere in the network and it took much longer to diagnose and fix.

Aside from Cloudflare clearly having systemic issues with actually testing code and validating configurations prior to ‘testing’ on Prod, this ought to serve as a major warning to anyone else who feels that a ‘quick deployment on Prod’ isn’t such a big deal. Many of us have dealt with companies where testing and development happened on Staging, and the real staging on Prod. Even if it’s management-enforced, that doesn’t help much once stuff catches on fire and angry customers start lighting up the phone queue.

Raspberry Pi Gets Desktop Form Factor

December 28, 2025 by 9 Comments

Before the Raspberry Pi came out, one cheap and easy way to get GPIO on a computer with a real operating system was to manipulate the pins on an old parallel port, then most commonly used for printers. Luckily, as that port became obsolete we got the Raspberry Pi, which has the GPIO and a number of other advantages over huge desktop computers from the 90s and 00s as well. But if you really miss that form factor or as yearn for the days of the old parallel port, this build which puts a Raspberry Pi into a mini ITX desktop case is just the thing for you.

There are a few features that make this build more than just a curiosity. The most obvious is that the Pi actually has support for PCIe and includes a single PCIe x1 slot which could be used for anything from a powerful networking card to an NVMe to a GPU for parallel computing in largely the same way that any desktop computer might them. The Pi Compute Module 5 that this motherboard is designed for doesn’t provide power to the PCIe slots automatically though, but the power supply that can be installed in the case should provide power not only to the CM5 but to any peripherals or expansion cards, PCIe or otherwise, that you could think of to put in this machine.

Of course all the GPIO is also made easily accessible, and there are also pins for installing various hats on the motherboard easily as well. And with everything installed in a desktop form factor it also helps to improve the cable management and alleviate the rats-nest-of-wires problems that often come with Pi-based projects. There’s also some more information on the project’s Hackaday.io page. And, if you’re surprised that Raspberry Pis can use normal graphics cards now, make sure to take a look at this build from a few years ago that uses completely standard gaming GPUs on the Pi 5.

Moving Mousepad Is An Elegant Aimbot

December 27, 2025 by 6 Comments

These days, it can be hard to remain competitive in online shooters without spending your entire life dedicated to the sport. This leads some to explore the world of competitive aids. (AKA: cheating.) A great example is [Nick], who built a mechanical aimbot to help in this regard.

[Nick’s] build moves a mousepad underneath the mouse opposite to the desired movement direction, in order to simulate the mouse movements required to aim at targets in game. This is achieved with the aid of a XDraw A4 pen plotter, which served as a cheap prebuilt X-Y motion platform. The plotter responds to simple serial commands, which makes it easy to control. The X-Y gantry was mounted underneath the desk so the mousepad sits seamlessly on top of the desk, sliding neatly on low-friction mouse skate stickers.

With the mousepad control system built, it was then necessary to figure out how to turn it into an aimbot. [Nick] already had a machine vision tool to detect enemies in shooting game, so it was merely modified to make the right mousepad movements to get the crosshairs right where they needed to be before firing. In testing, it proved more than capable at helping a new player achieve far superior aim, as a good aimbot should.

We’ve featured similar projects before that use complex mechanical contraptions to aim for you. Yes, it’s still cheating, but it’s a lot harder to detect than a traditional aimbot. That doesn’t make it right, per se, just more subtle. Video after the break. Continue reading “Moving Mousepad Is An Elegant Aimbot” →

What To Do When Your Foucault Pendulum Stops Swinging

December 27, 2025 by 18 Comments

At the Houston Museum of Natural Science they recently made a disturbing discovery: their Foucault pendulum had stopped swinging for the first time since its installation in the 1970s. (Video, embedded below.)

While some might take this as yet another sign of the end times, here it is simply a sign that the electromagnetic system that kicks the pendulum developed a fault and will need to be fixed.

Their explainer video of this Herzstein Foucault pendulum is also worth watching, as it explains both the underlying physics and this particular pendulum’s construction. Every 48 hours the 81.6 kg heavy pendulum completes a full rotation, like clockwork, with pins along the circumference being tipped over one by one as the pendulum precesses.

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A red and blue visualization of the waves from a small ultrasonic speaker

Seeing Sound For Under $200

December 27, 2025 by 2 Comments

There are five general senses: touch for feels, taste for food, smell for avoiding trash, hearing for sounds, and, of course, eyesight for visualizing the very waves making up that sound. [PlasmatronX] drives that last point home with his camera for sound waves, that’s even able to capture constructive and destructive interference. (Video, embedded below.)

You may have heard of Schlieren imaging, which is usually used to capture the movement of air currents caused by heat sources. [PlasmatronX] sets up a concave mirror to amplify the refraction of different densities of air, only unlike traditional Schlieren setups, he’s after the different densities of air caused by the pressure waves that we interpret as sound.

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