Head To Print Head: CNC Vs FDM

June 23, 2025 by Tyler August 18 Comments

It’s a question new makers often ask: “Should I start with a CNC machine or a 3D Printer?”– or, once you have both, every project gets the question “Should I use my CNC or 3D printer?” — and the answer is to both is, of course, “it depends”. In the video embedded below by [NeedItMakeIt] you can see a head-to-head comparison for one specific product he makes, CRATER, a magnetic, click-together stacking tray for tabletop gaming. (He says tabletop gaming, but we think these would be very handy in the shop, too.)

[NeedItMakeIt] takes us through the process for both FDM 3D Printing in PLA, and CNC Machining the same part in walnut. Which part is nicer is absolutely a matter of taste; we can’t imagine many wouldn’t chose the wood, but de gustibus non disputandum est–there is no accounting for taste. What there is accounting for is the materials and energy costs, which are both surprising– that walnut is cheaper than PLA for this part is actually shocking, but the amount of power needed for dust collection is something that caught us off guard, too.

Of course the process is the real key, and given that most of the video follows [NeedItMakeIt] crafting the CNC’d version of his invention, the video gives a good rundown to any newbie just how much more work is involved in getting a machined part ready for sale compared to “take it off the printer and glue in the magnets.” (It’s about 40 extra minutes, if you want to skip to the answer.) As you might expect, labour is by far the greatest cost in producing these items if you value your time, which [NeedItMakeIt] does in the spreadsheet he presents at the end.

What he does not do is provide an answer, because in the case of this part, neither CNC or 3D Printing is “better”. It’s a matter of taste– which is the great thing about DIY. We can decide for ourselves which process and which end product we prefer. “There is no accounting for taste”, de gustibus non disputandum est, is true enough that it’s been repeated since Latin was a thing. Which would you rather, in this case? CNC or 3D print? Perhaps you would rather 3D Print a CNC? Or have one machine to do it all? Let us know in the comments for that sweet, sweet engagement.

While you’re engaging, maybe drop us a tip, while we offer our thanks to [Al] for this one.

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Eulogy For The Satellite Phone

June 23, 2025 by Al Williams 54 Comments

We take it for granted that we almost always have cell service, no matter where you go around town. But there are places — the desert, the forest, or the ocean — where you might not have cell service. In addition, there are certain jobs where you must be able to make a call even if the cell towers are down, for example, after a hurricane. Recently, a combination of technological advancements has made it possible for your ordinary cell phone to connect to a satellite for at least some kind of service. But before that, you needed a satellite phone.

On TV and in movies, these are simple. You pull out your cell phone that has a bulkier-than-usual antenna, and you make a call. But the real-life version is quite different. While some satellite phones were connected to something like a ship, I’m going to consider a satellite phone, for the purpose of this post, to be a handheld device that can make calls.

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Earth’s Oxygen Levels And Magnetic Field Strength Show Strong Correlation

June 23, 2025 by Maya Posch 19 Comments

Time series of O2 (blue) and VGADM (red). (Credit: Weijia Kuang, Science Advances, 2025)

In an Earth-sized take on the age-old ‘correlation or causality’ question, researchers have come across a fascinating match between Earth’s magnetic field and its oxygen levels since the Cambrian explosion, about 500 million years ago. The full results by [Weijia Kuang] et al. were published in Science Advances, where the authors speculate that this high correlation between the geomagnetic dipole and oxygen levels as recorded in the Earth’s geological mineral record may be indicative of the Earth’s geological processes affecting the evolution of lifeforms in its biosphere.

As with any such correlation, one has to entertain the notion that said correlation might be spurious or indirectly related before assuming a strong causal link. Here it is for example known already that the solar winds affect the Earth’s atmosphere and with it the geomagnetic field, as more intense solar winds increase the loss of oxygen into space, but this does not affect the strength of the geomagnetic field, just its shape. The question is thus whether there is a mechanism that would affect this field strength and consequently cause the loss of oxygen to the solar winds to spike.

Here the authors suggest that the Earth’s core dynamics – critical to the geomagnetic field – may play a major role, with conceivably the core-mantle interactions over the course of millions of years affecting it. As supercontinents like Pangea formed, broke up and partially reformed again, the impact of this material solidifying and melting could have been the underlying cause of these fluctuations in oxygen and magnetic field strength levels.

Although hard to say at this point in time, it may very well be that this correlation is causal, albeit as symptoms of activity of the Earth’s core and liquid mantle.

Visual Code Generator To End All Generators

June 23, 2025 by Ian Bos 20 Comments

QR codes are something that we all take for granted in this day and age. There are even a million apps to create your own QR codes, but what if you want to make a barcode? How about making a specific kind of barcode that follows UPC-E, CODE 39, or even the infamous… CODABAR? Well, it might be more difficult to find a single app that can handle all those different standards. Using “yet-another-web-app”, Barcode Tool – Generator & Scanner, you can rid these worries, created by [Ricardo de Azambuja].

When going to [Ricardo]’s simple application, you will find a straightforward interface that allows you to make far more different strips and square patterns than you’ve ever imagined. Of course, starting with the common QR code, you can create custom overlaid codes like many other QR generators. More uniquely, there are options for any barcode under the sun to help organize your hacker workspace. If you don’t want to download an app to scan the codes, you can even use the included scanner function.

If you want to use the web app, you can find it here! In-depth solutions to rather simple problems are something we strive to provide here at Hackaday, and this project is no exception. However, if you want something more physical, check out this specialized outdoor city cooking station.

A piano is pictured with two hands playing different notes, G outlined in orange and C outlined in blue.

AI Piano Teacher To Criticize Your Every Move

June 22, 2025 by Ian Bos 15 Comments

Learning new instruments is never a simple task on your own; nothing can beat the instant feedback of a teacher. In our new age of AI, why not have an AI companion complain when you’re off note? This is exactly what [Ada López] put together with their AI-Powered Piano Trainer.

The basics of the piano rely on rather simple boolean actions, either you press a key or not. Obviously, this sets up the piano for many fun projects, such as creative doorbells or helpful AI models. [Ada López] started their AI model with a custom dataset with images of playing specific notes on the piano. These images then get fed into Roboflow and trained using the YOLOv8 model.

Using the piano training has the model run on a laptop and only has a Raspberry Pi for video, and gives instant feedback to the pianist due to the demands of the model. Placing the Pi and an LCD screen for feedback into a simple enclosure allows the easy viewing of how good an AI model thinks you play piano. [Ada López] demos their device by playing Twinkle Twinkle Little Star but there is no reason why other songs couldn’t be added!

While there are simpler piano trainers out there relying on audio cues, this project presents a great opportunity for a fun project for anyone else wanting to take up the baton. If you want to get a little more from having to do less in the physical space, then this invisible piano is perfect for you!

3D Print Glass, Using Accessible Techniques

June 22, 2025 by Jenny List 21 Comments

When seeing a story from MIT’s Lincoln Labs that promises 3D printing glass, our first reaction was that it might use some rare or novel chemicals, and certainly a super-high-tech printer. Perhaps it was some form of high-temperature laser sintering, unlikely to be within the reach of mere mortals. How wrong we were, because these boffins have developed a way to 3D print a glass-like material using easy-to-source materials and commonly available equipment.

The print medium is sodium silicate solution, commonly known as waterglass, mixed with silica and other inorganic nanoparticles. It’s referred to as an ink, and it appears to be printed using a technique very similar to the FDM printers we all know. The real magic comes in the curing process, though, because instead of being fired in a special furnace, these models are heated to 200 Celsius in an oil bath. They can then be solvent cleaned and are ready for use. The result may not be the fine crystal glass you may be expecting, but we can certainly see plenty of uses for it should it be turned into a commercial product. Certainly more convenient than sintering with a laser cutter.

Hackaday Links: June 22, 2025

June 22, 2025 by Dan Maloney 16 Comments

Hold onto your hats, everyone — there’s stunning news afoot. It’s hard to believe, but it looks like over-reliance on chatbots to do your homework can turn your brain into pudding. At least that seems to be the conclusion of a preprint paper out of the MIT Media Lab, which looked at 54 adults between the ages of 18 and 39, who were tasked with writing a series of essays. They divided participants into three groups — one that used ChatGPT to help write the essays, one that was limited to using only Google search, and one that had to do everything the old-fashioned way. They recorded the brain activity of writers using EEG, in order to get an idea of brain engagement with the task. The brain-only group had the greatest engagement, which stayed consistently high throughout the series, while the ChatGPT group had the least. More alarmingly, the engagement for the chatbot group went down even further with each essay written. The ChatGPT group produced essays that were very similar between writers and were judged “soulless” by two English teachers. Go figure.

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