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Hackaday Links: December 21, 2025

December 21, 2025 by 8 Comments

It’s amazing how fragile our digital lives can be, and how quickly they can fall to pieces. Case in point: the digital dilemma that Paris Buttfield-Addison found himself in last week, which denied him access to 20 years of photographs, messages, documents, and general access to the Apple ecosystem. According to Paris, the whole thing started when he tried to redeem a $500 Apple gift card in exchange for 6 TB of iCloud storage. The gift card purchase didn’t go through, and shortly thereafter, the account was locked, effectively bricking his $30,000 collection of iGadgets and rendering his massive trove of iCloud data inaccessible. Decades of loyalty to the Apple ecosystem, gone in a heartbeat.

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Pause Print, Add Hardware, And Enjoy Strength

December 21, 2025 by 14 Comments

3D Printing is great, but it is pretty much the worst way to make any given part– except that every other technique you could use to make that part is too slow and/or expensive, making the 3D print the best option. If only the prints were stiffer, stronger, more durable! [JanTech Engineering] feels your plight and has been hacking away with the M601 command to try embedding different sorts of hardware into his prints for up to 10x greater strength, as seen in the video embedded below.

It’s kind of a no-brainer, isn’t it? If the plastic is the weak point, maybe we could reinforce the plastic. Most concrete you see these days has rebar in it, and fiber-reinforced plastic is the only way most people will use resin for structural applications. So, how about FDM? Our printers have that handy M601 “pause print” command built in. By creatively building voids into your parts that you can add stronger materials, you get the best of all possible worlds: the exact 3D printed shape you wanted, plus the stiffness of, say, a pulltruded carbon-fiber rod.

[JanTech] examines several possible inserts, including the aforementioned carbon rods. He takes a second look at urethane foam, which we recently examined, and compares it with less-crushable sand, which might be a good choice when strength-to-weight isn’t an issue. He doesn’t try concrete mix, but we’ve seen that before, too. Various metal shapes are suggested — there are all sorts of brackets and bolts and baubles that can fit into your prints depending on their size — but the carbon rods do come out ahead on strength-to-weight, to nobody’s surprise.

You could do a forged carbon part with a printed mold to get that carbon stiffness, sure, but that’s more work, and you’ve got to handle epoxy resins that some of us have become sensitized to. Carbon rods and tubes are cheap and safer to work with, though be careful cutting them.

Finally, he tries machining custom metal insets with his CNC machine. It’s an interesting technique that’s hugely customizable, but it does require you to have a decent CNC available, and, at that point, you might want to just machine the part. Still, it’s an interesting hybrid technique we haven’t seen before.

Shoving stuff into 3D-printed plastic to make it a better composite object is a great idea and a time-honored tradition. What do you put into your prints? We’d love to know, and so would [Jan]. Leave a comment and let us know.

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Why Chopped Carbon Fiber In FDM Prints Is A Contaminant

December 21, 2025 by 28 Comments

A lot of claims have been made about the purported benefits of adding chopped carbon fiber to FDM filaments, but how many of these claims are actually true? In the case of PLA at least, the [I built a thing] channel on YouTube makes a convincing case that for PLA filament, the presence of chopped CF can be considered a contaminant that weakens the part.

Using the facilities of the University of Basel for its advanced imaging gear, the PLA-CF parts were subjected to both scanning electron microscope (SEM) and Micro CT imaging. The SEM images were performed on the fracture surfaces of parts that were snapped to see what this revealed about the internal structure. From this, it becomes apparent that the chopped fibers distribute themselves both inside and between the layers, with no significant adherence between the PLA polymer and the CF. There is also evidence for voids created by the presence of the CF.

To confirm this, an intact PLA-CF print was scanned using a Micro CT scanner over 13 hours. This confirmed the SEM findings, in that the voids were clearly visible, as was the lack of integration of the CF into the polymer. This latter point shouldn’t be surprising, as the thermal coefficient of PLA is much higher than that of the roughly zero-to-negative of CF. This translates into a cooling PLA part shrinking around the CF, thus creating the voids.

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A Compact, Browser-Based ESP32 Oscilloscope

December 21, 2025 by 24 Comments

An oscilloscope is usually the most sensitive, and arguably most versatile, tool on a hacker’s workbench, often taking billions of samples per second to produce an accurate and informative representation of a signal. This vast processing power, however, often goes well beyond the needs of the signals in question, at which point it makes sense to use a less powerful and expensive device, such as [MatAtBread]’s ESP32 oscilloscope.

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Shoot Instax Film In A Polaroid Camera With The Aid Of Tape

December 21, 2025 by 5 Comments

Polaroid cameras have been very popular for a very long time and are especially hot gifts this year. Fresh film is easy to find but relatively expensive. In contrast, Fuji’s Instax line of instant film and cameras aren’t as well established, but the film is easy to find and cheap. You might like to shoot cheap Instax film in your Polaroid camera. Thankfully, [Nick LoPresti] figured out how to do just that.

You can’t just slam an Instax cassette in an old Polaroid camera and expect it to work. The films are completely different sizes, and there’s no way they will feed properly through the camera’s mechanisms at all. Instead, you have to get manual about things. [Nick] starts by explaining the process of removing Instax film sheets from a cassette, which must be done without exposure to light if you want the film to remain useful. Then, if you know what you’re doing, you can tape it in place behind the lens of an old-school Polaroid camera, and expose it as you would any other shot. The chemistry is close enough that you’ll have a fair chance of getting something with passable exposure.

Once exposed, you have to develop the film. Normally, a Polaroid camera achieves this by squeezing the film sheet out through rollers to release the developer and start the process. Without being able to rely on the camera’s autofeed system, you need to find an alternative way to squeeze out the chemicals and get the image to develop. [Nick] recommends a simple kitchen rolling pin, while noting that you might struggle with some uneven chemical spread across the sheet. Ultimately, it’s a fussy hack, but it does work. It might only be worthwhile if you’ve got lots of Instax film kicking around and no other way to shoot it.

Instant cameras can seem a little arcane, but they’re actually quite simple to understand once you know how they’re built. You can even 3D print one from scratch if you’re so inclined. Video after the break.

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A Heavily Modified Rivian Attempts The Cannonball Run

December 21, 2025 by 55 Comments

There are few things more American than driving a car really fast in a straight line. Occasionally, the cars will make a few left turns, but otherwise, this is the pinnacle of American motorsport. And there’s no longer, straighter line than that from New York to Los Angeles, a time trial of sorts called the Cannonball Run, where drivers compete (in an extra-legal fashion) to see who can drive the fastest between these two cities. Generally, the cars are heavily modified with huge fuel tanks and a large amount of electronics to alert the drivers to the presence of law enforcement, but until now, no one has tried this race with an EV specifically modified for this task.

The vehicle used for this trial was a Rivian electric truck, chosen for a number of reasons. Primarily, [Ryan], the project’s mastermind, needed something that could hold a significant amount of extra batteries. The truck also runs software that makes it much more accepting of and capable of using an extra battery pack than other models. The extra batteries are also from Rivians that were scrapped after crash tests. The team disassembled two of these packs to cobble together a custom pack that fits in the bed of the truck (with the tonneau closed), which more than doubles the energy-carrying capacity of the truck.

Of course, for a time trial like this, an EV’s main weakness is going to come from charging times. [Ryan] and his team figured out a way to charge the truck’s main battery at one charging stall while charging the battery in the bed at a second stall, which combines for about a half megawatt of power consumption when it’s all working properly and minimizes charging time while maximizing energy intake. The other major factor for fast charging the battery in the bed was cooling, and rather than try to tie this system in with the truck’s, the team realized that using an ice water bath during the charge cycle would work well enough as long as there was a lead support vehicle ready to go at each charging stop with bags of ice on hand.

Although the weather and a few issues with the double-charging system stopped the team from completing this run, they hope to make a second attempt and finish it very soon. They should be able to smash the EV record, currently held by an unmodified Porsche, thanks to these modifications. In the meantime, though, there are plenty of other uses for EV batteries from wrecked vehicles that go beyond simple transportation.

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A Tiny Reflecting Telescope For Portable Astronomy

December 20, 2025 by 10 Comments

For most of us who are not astronomers, the image that comes to mind when describing a reflecting telescope is of a huge instrument in its own domed-roof building on a mountain top. But a reflecting telescope doesn’t have to be large at all, as shown by the small-but-uncompromising design from [Lucas Sifoni].

Using an off-the-shelf mirror kit with a 76mm diameter and a 300mm focal length, he’s made a pair of 3D-printed frames that are joined by carbon fibre rods. The eyepiece and mirror assembly sit in the front 3D-printed frame, and the eyepiece is threaded so the telescope can be focused. There’s a 3D-printed azimuth-elevation mount, and once assembled, the whole thing is extremely compact.

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