How To Grow A Giant Crystal From Copper Sulfate

October 5, 2026 by 15 Comments

Copper sulfate crystals are probably among one of the prettiest crystals you can grow at home, with even just a simple setup with some copper scrap and vinegar already capable of producing lots of them. Yet what if you want to grow really big ones? In that case the [Crystalverse] has got your back, with a recent video that expands on an older blog post.

In lieu of the copper-and-vinegar approach you can also obtain copper sulfate directly, since it’s a common fungicide, rootkiller as well as drying agent. This means that your local brick-and-mortar retailer or favorite online store probably has a few kg of the stuff available for sale.

As with most large crystal growing procedures the key is to have a saturated solution, which for copper sulfate just takes near-boiling water, to create a mesmerizingly blue liquid if there are no contaminants in it. By adding slightly more copper sulfate there are also crystallization sites on the bottom of the jar to draw these away from your large crystal.

From there it’s the same as with growing other large crystals – even those from sugar – with a seed crystal suspended into the solution, along with a silent prayer to the crystal gods that said seed crystal continues to grow without any defects. One gotcha with copper sulfate crystals is that the intense blue color is largely due to the presence of water molecules. This means that once it dehydrates, it turns effectively white.

Also of note that is the slower the crystal grows, the better the result is likely to be. During the months that it takes for these large crystals to grow, you need to carefully manage the copper sulfate solution, remove competing crystals on the bottom of the container and keep the temperature as constant as possible.

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Failing To Make A Fanless PC

October 5, 2026 by 31 Comments

The discerning modern gamer’s quest is to find a quieter computer without sacrificing performance. That proves challenging when modern components are highly efficient at producing monumental quantities of thermal energy. So the typical solution ends up moving enough air through the computer to create a rather tumultuous racket. So why have fans at all? Well, as [Billet Labs] demonstrates, that’s not necessarily a good idea. 

The build begins with a block of aluminum which, with a bit of hand-metal work, may become the base of the PC “case.” A dry-fit of the aesthetically modified parts taken from a previous attempt at a fanless PC reveals the steampunk aesthetic that defines the build. On final assembly, a large amount of thermal paste under the flex ATX power supply and 6mm of thermal pads under the motherboard provide passive cooling to the block of aluminum they are attached to

The cooling loop begins with three radiators: a big one, a small one, and a slightly smaller one. But raw metal PC radiators are difficult and expensive to come by these days. Some paint stripping and polishing will fix that problem. A few hand-made mounting brackets complete the aesthetic. All three radiators are stacked above the motherboard, and on top of each other, positioned horizontally to encourage passive airflow through them.

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How A British Engineer Homebrewed The Quietest Carbine

October 5, 2026 by 26 Comments

Hollywood has a lot to answer for when it comes to “silencers” on firearms. On screen, a suppressed pistol makes a pinging thud, and the bad guy in the next room flops to the floor. Real life is rather less cinematic. A suppressor takes the edge off the report, but it’s by no means quiet or silent. Hence why the term “silencer” is more of a colloquialism, and why “suppressor” is more appropriate.

Every so often, though, someone gets remarkably close to the movie version. The best-known example is probably the De Lisle carbine. A British commando weapon from the Second World War, it was cobbled together from bits and pieces and ended up being a stellar performer in the world of clandestine operations.

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A pair of red, articulated, 3D printed hands are being used to pour water from a plastic bottle into a glass. One hand holds the bottle, and one holds the glass.

Building A Cheap, Dexterous Robot Hand

October 5, 2026 by 8 Comments

Most of the time, assuming nothing’s gone wrong with them, we take our hands so much for granted that it’s easy to forget what remarkable pieces of engineering they are: not only are they precise and sensitive enough to crack an egg or write a signature, but also strong enough to lift a weight or swing a hammer. Such performance has thus far eluded robot hands, but fortunately few tasks require it; the main challenge is dexterity, which is where [Vittorio Lumare]’s low-cost Yeah Hand could help.

The Yeah Hand is mostly 3D-printed and uses five servo motors per hand; like a human hand, it has no actuators within the fingers themselves, instead using fishing-line tendons to transfer motion from the motors. To reduce friction and keep the motors from overheating, each tendon runs through guides made from PTFE Bowden tubes; in tests, the hand ran 800 cycles of opening and closing without even getting close to overheating. The hand can lift up to eight kilograms and apply a maximum grasping force of five kg. For better grip, each finger has silicone grips along the inner surface, which let it hold smooth objects quite steady; to pick up fine objects, the thumbs have thumbnails.

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The FPGA Chronicles: Open Source It

October 5, 2026 by 9 Comments

Last time, we looked at getting started with the GOWIN tools and a Tang Nano 20K FPGA. The software from GOWIN isn’t bad, but it isn’t open source, and there are a few oddities about it. In addition, simulation is through a third-party simulation package that has undergone some changes since an acquisition. There are tons of free simulation programs that are extremely good, and there is an open-source toolchain for the FPGA.

You could go grab everything you need piece by piece. But you don’t have to. There are several efforts to produce a toolchain from all the different pieces. We’re going to look at APIO.

APIO

APIO isn’t so much an FPGA toolchain project as it is an aggregator of toolchain projects. It reminded us of PlatformIO, and notes that it was inspired by it. It updates the tools you need, includes its own libraries, and gives you a common workflow across the FPGAs it supports.

You can download it for the command line, but you can also install it as a Visual Studio Code extension, which is what I did. You have to create a simple file that describes your project, and that’s about it.

Install Problems

Since APIO has its own libraries, it is possible that you will find some conflicts with your system libraries. In my case, the libreadline.so.8 file (in ~/.apio/bin/_internal) was causing problems that prevented anything from working. I simply renamed it out of the way, or you can just delete it. That took care of the problem.

Keep in mind that APIO just orchestrates a bunch of other tools like Yosys and GTKWave. Even if you have your own versions, APIO expects to use its private copies. For example, GTKWave on my system is a different version than the APIO copy, and if I try to read wave files without using APIO, I get error messages. You can, however, open a shell from the Tools/Misc menu of the APIO panel in Visual Studio Code.

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Porting Video Games To VHS

October 5, 2026 by 11 Comments

Although VHS-based games have existed for about as long as VHS players have sat in millions of living rooms, they always tended to be rather sparse gaming experiences. For example, the ActionMax gaming “console” that [Throaty Mumbo] shows off in his most recent video. You use a zapper to purportedly shoot down on-screen targets in “games” like Sonic Fury. After this disappointing experience, he figured he should probably make his own interpretation of a VHS-based video game.

This involves a DE1-SoC FPGA board along with an RP2350 MCU. There’s also an in-progress GitHub repository for those who wish to follow along. Rather than the simplistic Action Max system that plays exactly the same every time along with a basic light gun feature, this actually allows for interactive gameplay.

The video shows that the VHS tape contains both binary data for the game, as well as a number of video streams. This is decoded using the DE1’s composite input, with the RP2350 then acting on the decoded game data and handling input from the controller. With this, interesting effects can be accomplished, such as background video streams for the original Super Mario Bros.

Other demos include Night Trap and a variant of Doom that uses prerecorded video segments along with action events requiring you to press a specific button. Since there’s actual bytecode involved, quite a few more options are available for game development that could have been interesting to a 1980s audience.

It is hard to imagine how hard it was to get the VCR into homes, only for it to vanish again.

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Conveyor Belt GBoard Brings The Keys To You

October 5, 2026 by 19 Comments

It must be April in October again, because Google Japan has a new, hilariously impractical reimagining of the keyboard: a conveyor belt. This time it’s on GitHub with firmware, STLs, and a full build guide if you, too, want to wait a full cycle to get the ‘backspace’ key whenever you make a typo, or to write such fun words as “ooid” or “princesship”.

You can watch it in action in the video embedded below, but just the photo probably gives you the idea: the four staggered rows of keys are each 3D-printed chains holding mechanical key switches, driven from a motor in the base. Each row also has a flexible PCB to keep everything wired together, though it’s unclear how those electrical impulses from the key presses get off the conveyor belt and into your computer. That part of the build guide is “TBD” and the source code doesn’t appear to be complete.

Those details may be forthcoming, or it might never be revealed because this is obviously a joke, but now that they’ve gone to the effort of providing STLs, we’re now invested in figuring out how to actually make it work. A BLE-equipped microcontroller in each belt? RFID tags on each key, with readers in the base? SMD LEDs on the flex PCB that flash out the ASCII code of each pressed key as they whiz past a sensor? In theory, any of those should work, but which should we use? You decide!

We like Google Japan and their weird keyboards, and we have to say that compared to the hat from a few years ago, this one is almost practical, though the rotary-phone one wins on style points. In some ways, it occurs to us that this is the exact inverse of the chain printers of yesteryear.

Thanks to [CityZen] for the tip! If October for you is more “spooky” than “silly”, we still want to know about it. Or if you build any of the Gboards. Either way, let us know on the tips line what you’re up to.

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