A Linux Business Card You Can Build

It is a sign of the times that one of [Dmitry’s] design criteria for his new Linux on a business card is to use parts you can actually find during the current component shortage. The resulting board uses a ATSAMD21 chip and emulates a MIPS machine in order to boot Linux.

We like that in addition to the build details, [Dmitry] outlines a lot of the reasons for his decisions. There’s also a a fair amount of detail about how the whole system actually works. For example, by using a 0.8 mm PCB, the board can accept a USB-C cable with no additional connector. There is also a great explanation of the MIPS MMU and don’t forget that MIPS begat RISC-V, so many of the MIPS core details will apply to RISC-V as well (but not the MMU).  You’ll also find some critiques of the ATSAMD21’s DMA system. It seems to save chip real estate, the DMA system stores configuration data in user memory which it has to load and unload every time you switch channels.

By the end of the post you get the feeling this may be [Dimitry]’s last ATSAMD21 project. But we have to admit, it seems to have come out great. This isn’t the first business card Linux build we’ve seen. This one sure reminded us of a MIDI controller card we once saw.

Apple AirTags Hacked And Cloned With Voltage Glitching

Apple AirTags are useful little devices. They essentially use iPhones in the wild as a mesh network to tell the owner where the AirTag is. Now, researchers have shown that it’s possible to clone these devices.

The research paper explains the cloning process, which requires physical access to the hardware. To achieve the hack, the Nordic nRF52832 inside the AirTag must be voltage glitched to enable its debug port. The researchers were able to achieve this with relatively simple tools, using a Pi Pico fitted with a few additional components.

With the debug interface enabled, it’s simple to extract the microcontroller’s firmware. It’s then possible to clone this firmware onto another tag. The team also experimented with other hacks, like having the AirTag regularly rotate its ID to avoid triggering anti-stalking warnings built into Apple’s tracing system.

As the researchers explain, it’s clear that AirTags can’t really be secure as long as they’re based on a microcontroller that is vulnerable to such attacks. It’s not the first AirTag cloning we’ve seen either. They’re an interesting device with some serious privacy and safety implications, so it pays to stay abreast of developments in this area.

[Thanks to Itay for the tip!]

Building A Better 3D Scanner With An IPhone, And Making Art

Apple’s FaceID system uses infrared depth-sensing technology to authenticate people via their faces. It can also be used for simple 3D scanning, and [Scott Yu-Jan] found a better way to do that.

The main problem with using an iPhone as a 3D scanner in this manner is that the sensor is built into the front side of the device. It’s great for scanning your own face, but if you’re trying to scan an object, you can no longer see the iPhone’s screen. [Scott] solved this problem by slapping together a handheld 3D printed device to hold the iPhone along with an external monitor. This allowed Scott to scan while still seeing what was going on.

Having noticed that some of the 3D scanning apps produced strange, glitchy results when scanning faces, [Scott] decided to innovate artistically. He employed [Andrea] to model, took some scans, and Photoshopped the results into some impressive posters.

Overall, [Scott] demonstrates that it’s relatively easy to repurposed the iPhone for improved 3D scanning. With a simple design, he has a handheld scanner that works way better than just the phone on its own. Alternatively, consider getting into photogrammetry instead.

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Chinese Anti-Porn Helmet Raises Eyebrows, Questions

Did you know that pornography is completely illegal in China? Probably not surprising news, though, right? The country has already put measures in place to scour the Internet in search of explicit content, mostly using AI. But the government also employs human porn appraisers, called jian huang shi, whose job it is to judge images and videos to decide whether they contain explicit content. Also probably not surprising is that humans are better than AI at knowing porn when they see it — or at least, they are faster at identifying it. Weirdness and morality and everything else aside, these jian huang shi are regular people, and frankly, they get exhausted looking at this stuff all day.

So what is the answer to burnout in this particular field? Researchers at Beijing Jiaotong University have come up with a way to bring the technological and human aspects of their existing efforts together. They’ve created a helmet that can detect particular spikes in brainwaves that occur from exposure to explicit imagery. Basically, it flashes a combination of naughty and ho-hum images in rapid succession until a spike is detected, then it flags the offending image.

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It’s Linux. On An ESP32

By today’s standards, the necessities for running a Linux-based operating system are surprisingly meagre in terms of RAM and processor power. Back in the day we ran earlier Linux versions on Intel 386 and 486 machines with tiny quantities of memory compared to the multi-gigabyte many-core powerhouses we do today.

So it stands to reason that many of the more powerful microcontrollers should also run Linux, but of course they are often unable because the lack a memory management unit. The original ESP32 is just such a candidate, plenty of power but unable to run Linux. Not so fast, because [Dror Gluska] has managed to boot a Linux kernel on Espressif’s dual-core chip. How on earth? By emulating a RISC-V processor on it and booting a RISC-V version of the kernel.

The emulator in question is [Fabrice Belard]’s TinyEMU, a piece of software that brings both RISC-V and x86 to limited-spec platforms, and the write-up describes the extensive optimization and tracing of ESP32 bottlenecks which was finally able to get a Linux kernel booting in 1 minute and 35 seconds. Of course it’s simply an exercise to prove it can be done and we won’t be seeing Linux-based ESP projects any time soon, but it’s still an impressive piece of work.

This isn’t the lowest-spec microcontroller we’ve seen run Linux, back in 2012 we saw it on emulated ARM running on an 8-bit AVR.

Game Boy Repurposed Solely As A Camera

As much as we all love the Game Boy Camera, it’s really just an add-on to the popular handheld console. Twitter user [@thegameboycam] decided to build a dedicated camera platform using the hardware, and the result was the Game Boy DSLR.

Camera pedants will note that it’s not really a DSLR, but that’s not really the point. It’s a Game Boy with the camera accessory built into a proper camera-like housing. There’s a CS/C mount for the lens, and it’s got a custom shell with leatherette, just like the cameras of last century. It’s also got a cold shoe, and a 1/4″ screw thread for tripod mounting. Oh, and strap lugs! So you can really rock that old-school aesthetic with your tweed suit on.

More practical modern features include a 1800 mAh battery that charges over USB Type C and a backlit IPS display. The screen has been turned through 90 degrees, and the cartridge port and buttons are relocated to create a more traditional camera-like form factor. If you really want, though, you can still play it like a regular Game Boy. Just swap out the modified camera cart with the lens mount for a regular Game Boy Camera or another game cartridge.

It’s a fun hack that scores big on style points. No longer can you be the cool kid just by rocking a Game Boy with a big ol’ lens hanging off the back. Now you gotta compete with this!

Our tipsline is waiting for when you’ve got the next big thing in Game Boy Camera hacks. Video after the break.

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CP/M Is Now Freer Than It Was

It’s easy to think of the earlier history of desktop computing operating systems in terms of DOS, Windows, and Mac OS with maybe a bit of AmigaOS, TOS, or RiscOS thrown in. But the daddy of desktop computing, the OS that put word-processors and spreadsheets in 1970s offices and had a huge influence on what followed, isn’t among that list. Digital Research’s CP/M ran initially on Intel 8080-based machines before losing out to MS-DOS as IBM’s choice for their PC, and then gradually faded away over the 1980s. Its source has been available in some form with a few strings for a long time now, but now we have confirmation from Digital Research’s successor company that it’s now available without restrictions on where it can be distributed.

For years it was something an operating system that had been bypassed by the hardware and hacker communities, as the allure of GNU/Linux was stronger and most available CP/M capable machines were also 1980s 8-bit gaming platforms. But with the more recent increased popularity of dedicated retrocomputing platforms such as the RC2014 it’s become a more common sight in our community. Brush up your command line skills, and give it a go!

Header: Michael Specht, CC BY-SA 3.0.