2025-12-22 11:00:39
If you’ve ever experimented with a microprocessor at the bare metal level, you’ll know that when it starts up, it will look at its program memory for something to do. On an old 8-bit machine, that program memory was usually an EPROM at the start of its address space, while on a PC, it would be the BIOS or UEFI firmware. This takes care of initialising the environment in both hardware and software, and then loading the program, OS, or whatever the processor does. The Raspberry Pi, though, isn’t like that, and [Patrick McCanna] is here to tell us why.
The Pi eschews bringing up its ARM core first. Instead, it has a GPU firmware that brings up the GPU. It’s this part of the chip that then initialises all peripherals and memory. Only then does it activate the ARM part of the chip. As he explains, this is because the original Pi chip, the BCM2835, is a set-top-box chip. It’s not an application processor at all, but a late-2000s GPU that happened to have an ARM core on a small part of its die, so the GPU wakes first, not the CPU. Even though the latest versions of the Pi have much more powerful Broadcom chips, this legacy of their ancestor remains. For most of us using the board it doesn’t matter much, but it’s interesting to know.
Fancy trying bare metal Pi programming? Give it a go. We’ve seen some practical projects that start at that level.
2025-12-22 08:00:55
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.
As for why the account was locked, it appears that the gift card Paris used had been redeemed previously — some kind of gift card fraud, perhaps. But Paris only learned that after the issue was resolved. Before that, he relates five days of digital limbo and customer support hell, which included unhelpful advice such as creating a new account and starting over from scratch, which probably would have led to exactly the same place, thanks to hardware linking of all his devices to the nuked account. The story ends well, perhaps partly due to the victim’s high profile in the Apple community, but it’s a stark lesson in owning your digital data. If they’re not your computer, they’re not your files, and if someone like Paris can get caught up in a digital disaster like this, it can happen to anyone.
Hackaday isn’t the place readers normally turn to for fiction, but we wanted to call attention to a piece of short fiction with a Hackaday angle. Back in June, Canadian writer Kassandra Haakman contacted us about a short story she wrote focused on the 1989 geomagnetic storm that temporarily wiped out the electric grid in Québec. She wanted permission to quote our first-hand description of that night’s aurorae, which we wrote a bit about on these pages. We happily granted permission for the quote, on condition that she share a link to the article once it’s published. The story is out now; it’s a series of vignettes from that night, mostly looking at the disorientation of waking up to no electricity but a sky alive with light and energy. Check it out — we really enjoyed it.
Speaking of solar outbursts, did 6,000 Airbus airliners really get grounded because of solar storms? We remember feeling a bit skeptical when this story first hit the media, but without diving into it at the time, cosmic rays interfering with avionics seemed as good an explanation as anything. But now an article in Astronomy.com goes into much more detail about this Emergency Airworthiness Directive and exactly what happened to force aviation authorities to ground an entire fleet of planes. The article speaks for itself, but to summarize, it appears that the EAD was precipitated by an “uncommanded and limited pitch down” event on a JetBlue flight on October 10 that injured several passengers. The post-incident analysis revealed that the computer controlling the jet’s elevators and ailerons may have suffered a cosmic-ray-induced “bit flip,” temporarily scrambling the system and resulting in uncommanded movement of the control surfaces. The article goes into quite some detail about the event and the implications of increased solar activity for critical infrastructure.
And finally, if you’ve been paying attention to automotive news lately, it’s been kind of hard to miss the brewing public relations nightmare Toyota is facing over the rash of engine failures affecting late-model Tundra pickups. The 3.4-liter V6 twin-turbo engine that Toyota chose to replace the venerable but thirsty 5.7-liter V8 that used to power the truck is prone to sudden death, even with very few miles on the odometer. Toyota has been very cagey about what exactly is going wrong with these engines, but Eric over at “I Do Cars” on YouTube managed to get his hands on an engine that gave up the ghost after a mere 38,000 miles, and the resulting teardown is very interesting. Getting to the bottom of the problem required a complete teardown of the engine, top to bottom, so all the engineering behind this power plant is on display. Everything looked good until the very end; we won’t ruin the surprise, but suffice it to say, it’s pretty gnarly. Enjoy!
2025-12-22 05:00:18
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.
2025-12-22 02:00:16
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.
What this means is that for PLA-CF, the presence of CF is by all measures an undesirable contaminant that effectively compromises it as much as having significant moisture in the filament before printing. Although for other thermoplastics used with FDM printing, chopped CF may make more sense, with PLA-CF, you’re effectively throwing away money for worse results.
As also noted in the video, in medical settings, these CF-reinforced FDM filaments aren’t permitted due to the chopped CF fragments. This topic has featured more widely in both the scientific literature and YouTube videos in recent years, with some significant indications that fragments of these chopped fibers can have asbestos-like implications when inhaled.
Meanwhile, are you’re looking for the thrill of a weird filament? Maybe try one of these.
2025-12-21 23:00:09
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.
The oscilloscope doesn’t have a display; instead, it hosts a webpage that displays the signal trace and provides the interface. Since the software uses direct memory access to continually read a signal from the ADC, it’s easy to adjust the sampling rate up to the hardware’s limit of 83,333 Hz. In addition to sampling-rate adjustment options, the browser interface includes a crosshair pointer for easy voltage reading, an adjustable trigger level, attenuation controls, and the ability to set the test signal frequency. The oscilloscope’s hardware is simply a Seeed Studio Xiao development board mounted inside a 3D-printed case with an AA battery holder and three pin breakouts for ground, signal input, and the test signal output.
This isn’t the first ESP32-based oscilloscope we’ve seen, though it is the fastest. If you’re looking for a screen with your simple oscilloscope, we’ve seen them built with an STM32 and Arduino. To improve performance, you might add an anti-aliasing filter.
2025-12-21 20:00:38
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.
