Reliable 3D Printing With Ceramic Slurry

June 16, 2023 by 4 Comments

3D printing is at its most accessible (and most affordable) when printing in various plastics or resin. Printers of this sort are available for less than the cost of plenty of common power tools. Printing in materials other than plastic, though, can be a bit more involved. There are printers now for various metals and even concrete, but these can be orders of magnitude more expensive than their plastic cousins. And then there are materials which haven’t really materialized into a viable 3D printing system. Ceramic is one of those, and while there are some printers that can print in ceramic, this latest printer makes some excellent strides in the technology.

Existing technology for printing in ceramic uses a type of ceramic slurry as the print medium, and then curing it with ultraviolet light to solidify the material. The problem with ultraviolet light is that it doesn’t penetrate particularly far into the slurry, only meaningfully curing the outside portions. This can lead to problems, especially around support structures, with the viability of the prints. The key improvement that the team at Jiangnan University made was using near-infrared light to cure the prints instead, allowing the energy to penetrate much further into the material for better curing. This also greatly reduces or eliminates the need for supports in the print.

The paper about the method is available in full at Nature, documenting all of the details surrounding this new system. It may be a while until this method is available to a wider audience, though. If you can get by with a print material that’s a little less exotic, it’s not too hard to get a metal 3D printer, as long as you are familiar with a bit of electrochemistry.

Thermal Camera Reviewed

June 16, 2023 by 13 Comments

We keep thinking about buying a better thermal camera, as there are plenty of advantages. While [VoltLog’s] review of the Topdon TC002 was interesting though, it has a connector for an iPhone. Even if you aren’t on Android, there is a rumor that Apple may (or may be forced to) change connectors which will make it more difficult to connect. Of course, there will be adapters, and you can get a USB C version of the same camera.

Technically, the camera is pretty typical of other recent cameras in this price range, and they probably all use the same image sensor. The camera provides 256×192 images.

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Long-Distance Wi-Fi With Steam Deck Server

June 16, 2023 by 11 Comments

It’s no secret that the Steam Deck is a powerful computer, especially for its price point. It has to be capable enough to run modern PC games while being comfortable as a handheld, all while having a useful amount of battery life. Thankfully Valve didn’t lock down the device like most smartphone manufacturers, allowing the computer to run whatever operating system and software the true owner of the device wants to run. That means that a whole world of options is open for this novel computer, like using it to set up an 802.11ah Wi-Fi network over some pretty impressive distances.

Of course the Steam Deck is more of a means to an end for this project; the real star of the show is DragonOS, a Debian-based Linux distribution put together by [Aaron] to enable easy access to the tools needed for plenty of software-defined radio projects like this one. Here, he’s using it to set up a long-distance Wi-Fi network on one side of a lake, then testing it by motoring over to the other side of the lake to access the data from the KrakenSDR setup running on the Deck, as well as performing real-time capture of IQ data that was being automatically demodulated and feed internally to whispercpp.

While no one will be streaming 4K video over 802.11ah, it’s more than capable of supporting small amounts of data over relatively large distances, and [Aaron] was easily able to SSH to his access point from over a kilometer away with it. If the lake scenery in the project seems familiar at all, it’s because this project is an extension of another one of his DragonOS projects using a slightly lower frequency to do some impressive direction-finding, also using the Steam Deck as a base of operations.

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Hinged Parts For The 8th Grade Set

June 16, 2023 by 8 Comments

I recently agreed to run a 3D printing camp for 8th graders. If you’ve never shared your knowledge with kids, you should. It is a great experience. However, it isn’t without its challenges. One thing I’ve learned: don’t show the kids things that you don’t want them to try to print.

I learned this, of course, the hard way. I have several “flexy”3D prints. You know the kind. Flexy dinosaurs, cats, hedgehogs, and the like. They all have several segments and a little hinge so the segments wobble. The problem is the kids wanted to print their own creations with flexy hinges.

I’ve built a few print-in-place hinges, but not using Tinkercad, the software of choice for the camp. While I was sure it was possible, it seemed daunting to get the class to learn how to do it. Luckily, there’s an easy way to add hinges like this to a Tinkercad design. There was only one problem.

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Hackaday Podcast 223: Smoking Smart Meter, 489 Megapixels, And Unshredding Documents

June 16, 2023 by 10 Comments

Elliot’s back from vacation, and Dan stepped into the virtual podcast studio with him to uncover all the hacks he missed while hiking in Italy. There was a lot to miss, what with a smart meter getting snuffed by a Flipper Zero — or was it? How about a half-gigapixel camera built out of an old scanner, or a sonar-aimed turret gun? We also looked at a couple of projects that did things the hard way, like a TV test pattern generator that was clearly a labor of love, and an all-transistor HP frequency counter. More plastic welding? Hey, a fix is a fix! Plus, we’ll dive into why all those Alexas are just gathering dust, and look at the really, REALLY hard problems involved in restoring shredded documents.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download a long series of ones and zeroes that, when appropriately interpreted, sound like two people talking about nerdy stuff!

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IKEA LACK Table Becomes Extremely Affordable DIY Copy Stand

June 16, 2023 by 14 Comments

A copy stand is a tool used to capture images of photos, artwork, books, and things of a similar nature. It holds a camera perpendicular to a large and flat surface, upon which the subject rests.

A threaded rod provides effective vertical adjustment.

They are handy, but there’s no need to spend a lot when [BlandPasta]’s DIY copy stand based on a cheap IKEA LACK table can be turned into an economical afternoon project with the help of simple hardware and a few 3D printed parts.

The main structure comes from a mixture of parts from two LACK tables: one small and one normal-sized. A tabletop is used as the bed, and the square legs make up the structural parts with the help of some printed pieces. A threaded rod combined with some captive hardware provides a way to adjust the camera up and down with a crank, while one can manually slide the horizontal camera mount as needed to frame the subject appropriately.

This is a clever remix of IKEA parts, and the somewhat matte white finish of the LACK complements photography well. Adding some DIY LED lighting is about all it takes to get a perfectly serviceable copy stand that won’t break the bank.

This Week In Security: ACME.sh, Leaking LEDs, And Android Apps

June 16, 2023 by 3 Comments

Let’s Encrypt has made an enormous difference to the landscape of the web. The protocol used for authenticating and receiving certificates, ACME, has spawned quite a few clients of various flavors. Some are written in Rust, some in Python or Go, and a few in straight Bash shell script. One of those last ones, acme.sh, was doing something odd when talking to a particular “Certificate Authority”, HiCA. This pseudo-CA only supports acme.sh, and now we know why. The folks behind HiCA found an RCE exploit in acme.sh, and decided to use that exploit to do certificate issuance with more “flexability”. Oof.

The nuts and bolts here is that HiCA was working as a CA-in-the-Middle, wrapping other CA’s authentication services. Those services don’t support ACME authentication at all, and HiCA used the acme.sh vulnerability to put the authentication token in the place SSL.com expected to find it. So, just a good community member offering a service that ACME doesn’t quite support, right?

Well, maybe not so innocent. The way it appears this works, is that the end user sends a certificate request to HiCA. HiCA takes that information, and initiates a certificate request off to SSL.com. SSL.com sends back a challenge, and HiCA embeds that challenge in the RCE and sends it to the end user. The end user’s machine triggers the RCE, which pushes the challenge token to the well-known location, and bypasses the ACME protection against exactly this sort of CA-in-the-middle situation.

The last piece of the authentication process is that the signing server reaches out over HTTP to the domain being signed, and looks for the token to be there. Once found, it sends the signed certificates to HiCA, who then forward them on to the end user. And that’s the problem. HiCA has access to the key of every SSL cert they handled. This doesn’t allow encryption, but these keys could be used to impersonate or even launch MitM attacks against those domains. There’s no evidence that HiCA was actually capturing or using those keys, but this company was abusing an RCE to put itself in the position to have that ability.

The takeaway is twofold. First, as an end user, only use reputable CAs. And second, ACME clients need to be hardened against potentially malicious CAs. The fact that HiCA only supported the one ACME client was what led to this discovery, and should have been a warning flag to anyone using the service. Continue reading “This Week In Security: ACME.sh, Leaking LEDs, And Android Apps” →