Using An E-Book Reader As A Secondary Display

December 23, 2025 by No comments

[Alireza Alavi] wanted to use an e-ink tablet as a Linux monitor. Why? We don’t need to ask. You can see the result of connecting an Onyx BOOX Air 2 to an Arch Linux box in the video below.

Like all good projects, this one had a false start. Deskreen sounds good, as it is an easy way to stream your desktop to a browser. The problem is, it isn’t very crisp, and it can be laggy, according to the post. Of course, VNC is a tried-and-true solution. The Onyx uses Android, so there were plenty of VNC clients, and Linux, of course, has many VNC servers.

Putting everything together as a script lets [Alireza] use the ebook as a second monitor. Using it as a main monitor would be difficult, and [Alireza] reports using the two monitors to mirror each other, so you can glance over at the regular screen for a color image, for example.

Another benefit of the mirrored screens is that VNC lets you use the tablet’s screen as an input device, which is handy if you are drawing in GIMP or performing similar tasks.

We sometimes use VNC on Android just to get to a fake Linux install running on the device.

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A photo of the SigCoreUC

SigCore UC: An Open-Source Universal I/O Controller For The Raspberry Pi

December 22, 2025 by 2 Comments

Recently, [Edward Schmitz] wrote in to let us know about his Hackaday.io project: SigCore UC: An Open-Source Universal I/O Controller With Relays, Analog I/O, and Modbus for the Raspberry Pi.

In the video embedded below, [Edward] runs us through some of the features which he explains are a complete industrial control and data collection system. Features include Ethernet, WiFi, and Modbus TCP connectivity, regulated 5 V bus, eight relays, eight digital inputs, four analog inputs, and four analog outputs. All packaged in rugged housing and ready for installation/deployment.

[Edward] says he wanted something which went beyond development boards and expansion modules that provided a complete and ready-to-deploy solution. If you’re interested in the hardware, firmware, or software, everything is available on the project’s GitHub page. Beyond the Hackaday.io article, the GitHub repo, the YouTube explainer video, there is even an entire website devoted to the project: sigcoreuc.com. Our hats off to [Edward], he really put a lot of polish on this project.

If you’re interested in using the Raspberry Pi for input/output you might also like to read about Raspberry Pi Pico Makes For Expeditious Input Device and Smart Power Strip Revived With Raspberry Pi.

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An HO Model Power Bogie For Not A Lot

December 22, 2025 by 1 Comment

For people who build their own model trains there are a range of manufacturers from whom a power bogie containing the motor and drive can be sourced. But as [Le petit train du Berry] shows us in a video, it’s possible to make one yourself and it’s easier than you might think (French language video with truly awful YouTube auto-translation).

At the heart of the design is a coreless motor driving a worm gear at each end that engages with a gear on each axle. The wheelsets and power pickups are off-the-shelf items. The chassis meanwhile is 3D printed, and since this is an ongoing project we see two versions in the video. The V5 model adds a bearing, which its predecessor lacked.

The result is a pretty good power bogie, but it’s not without its faults. The gear ratio used is on the high side in order to save height under a model train body, and in the version without a bearing a hard-wearing filament is required because PLA will wear easily. We’re guessing this isn’t the last we’ll see of this project, so we hope those are addressed in future versions.

We like this project and we think you will too after you’ve watched the video below the break. For more home-made model railway power, how about a linear motor?

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High-Speed Pocket Hot Dog Cooker

December 22, 2025 by 11 Comments

Few of us complain that hot dogs take too long to cook, because we buy them from a stand. Still, if you do have to make your own dog, it can be a frustrating problem. To solve this issue, [Joel Creates] whipped up a solution to cook hot dogs nearly instantaneously. What’s more, it even fits in your pocket!

The idea behind this build is the same as the classic Presto hot dog cooker—pass electricity through a hot dog frank, and it’ll heat up just like any other resistive heating element. To achieve this, [Joel] hooked up a lithium-polymer pack to a 12-volt to 120-volt inverter. The 120-volt output was hooked up to a frank, but it didn’t really cook much. [Joel] then realized the problem—he needed bigger electrodes conducting electricity into the sausage. With 120 volts pumping through a couple of bolts jammed into either end of the frank, he had it cooked in two minutes flat.

All that was left to do was to get this concept working in a compact, portable package. What ensued was testing with a variety of boost converter circuits to take power from the batteries and stepping it up to a high enough voltage to cook with. That, and solving the issue of nasty chemical byproducts produced from passing electricity through the sausages themselves. Eventually, [Joel] comes up with a working prototype which can electrically cook a hot dog to the point of shooting out violent bursts of steam in under two minutes. You’d still have to be pretty brave to eat something that came out of this thing.

The biggest problem with hot dogs remains that the franks are sold in packs of four while buns are sold in packs of six. Nobody’s solved that problem yet, except for those hateful people who inexplicably have eleven friends. If you solve that one, don’t hesitate to notify the tipsline. Don’t forget, either, that the common hot dog can make for an excellent LED tester. Video after the break.

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Christmas Ornament Has Hidden Compartment, Clever Design

December 22, 2025 by 2 Comments

If you need something clever for a gift, consider this two-part 3D-printed Christmas ornament that has a small secret compartment. But there’s a catch: the print is a challenging one. So make sure your printer is up to the task before you begin (or just mash PRINT and find out).

Want a challenging print that’s also useful? This two-piece ornament has a small gift area inside, and prints without supports.

This design is from [Angus] of [Maker’s Muse] and it’s not just eye-catching, but meticulously designed specifically for 3D printing. In fact, [Angus]’s video (embedded under the page break) is a great round-up of thoughtful design for manufacture (DFM) issues when it comes to filament-based 3D printing.

The ornament prints without supports, which is interesting right off the bat because rounded surfaces (like fillets, or a spherical surface) facing the build plate — even when slightly truncated to provide a flat bottom — are basically very sharp overhangs. That’s a feature that doesn’t generally end up with a good surface finish. [Angus] has a clever solution, and replaces a small section with a flat incline. One can’t tell anything is off by looking at the end result, but it makes all the difference when printing.

There are all kinds of little insights into the specific challenges 3D printing brings, and [Angus] does a fantastic job of highlighting them as he explains his design and addresses the challenges he faced. One spot in particular is the flat area underneath the hang hole. This triangular area is an unsupported bridge, and because of its particular shape, it is trickier to print than normal bridges. The workable solution consists of countersinking a smaller triangle within, but [Angus] is interested in improving this area further and is eager to hear ideas on how to do so. We wonder if he’s tried an approach we covered to get better bridges.

Want to print your own? 3D files are available direct from [Angus]’s site in a pay-what-you-like format. If your 3D printer is up to it, you should be able to make a few before Christmas. But if you’d prefer to set your sights on next year with something that uses power and hardware, this tiny marble machine ornament should raise some eyebrows.

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A grey and blue coreXY 3D printer is shown, with a small camera in place of its hotend. On the print bed is a ChArUco pattern, a grid of square tiles containing alternating black fill and printed patterns.

Calibrating A Printer With Computer Vision And Precise Timing

December 22, 2025 by 7 Comments

[Dennis] of [Made by Dennis] has been building a Voron 0 for fun and education, and since this apparently wasn’t enough of a challenge, decided to add a number of scratch-built improvements and modifications along the way. In his latest video on the journey, he rigorously calibrated the printer’s motion system, including translation distances, the perpendicularity of the axes, and the bed’s position. The goal was to get better than 100-micrometer precision over a 100 mm range, and reaching this required detours into computer vision, clock synchronization, and linear algebra.

To correct for non-perpendicular or distorted axes, [Dennis] calculated a position correction matrix using a camera mounted to the toolhead and a ChArUco board on the print bed. Image recognition software can easily detect the corners of the ChArUco board tiles and identify their positions, and if the camera’s focal length is known, some simple trigonometry gives the camera’s position. By taking pictures at many different points, [Dennis] could calculate a correction matrix which maps the printhead’s reported position to its actual position.

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Ask Hackaday: What Goes Into A Legible Font, And Why Does It Matter?

December 22, 2025 by 40 Comments

Two patent front pages, on the left American with a serif font, on the right British with a sans serif font.
American and British patents, for comparison.

There’s an interesting cultural observation to be made as a writer based in Europe, that we like our sans-serif fonts, while our American friends seem to prefer a font with a serif. It’s something that was particularly noticeable in the days of print advertising, and it becomes very obvious when looking at government documents.

We’ve brought together two 1980s patents from the respective sources to illustrate this, the American RSA encryption patent, and the British drive circuitry patent for the Sinclair flat screen CRT. The American one uses Times New Roman, while the British one uses a sans-serif font which we’re guessing may be Arial. The odd thing is in both cases they exude formality and authority to their respective audiences, but Americans see the sans-serif font as less formal and Europeans see the serif version as old-fashioned. If you thought Brits and Americans were divided by a common language, evidently it runs much deeper than that. Continue reading “Ask Hackaday: What Goes Into A Legible Font, And Why Does It Matter?” →