Author: Bryan Cockfield

1755 Articles

Using An Old Smartphone In Place Of A Raspberry Pi

April 27, 2023 by 63 Comments

The Raspberry Pi was a fairly revolutionary computing device when it came on the scene around a decade ago. Enough processing power to run a full Linux desktop and plenty of GPIO meant almost certain success. In the past year, though, they’ve run into some issues with their chip supplier and it’s been difficult to find new Pis, which has led to some looking for alternatives to these handy devices. [David] was hoping to build a music streaming server and built it on an old smartphone instead of the ubiquitous single-board computer.

Most smartphones are single-board computers though, and at least the Android devices are fully capable of running Linux just like the Pi. The only problem tends to be getting around the carrier or manufacturer restrictions like a locked bootloader or lack of root access. For [David]’s first try getting this to work, he tried to install Navidrome on a Samsung phone but had difficulties with the lack of memory and had to build the software somewhere else and then load it on the phone. It did work, but the stock operating system kept killing the process for consuming too much memory.

Without root access, [David] decided to try LineageOS, a version of Android which, among other benefits, is typically much more configurable than the stock version of Android that is shipped with smartphones. This allowed him to disable or uninstall anything not needed for his music server to free up enough memory. After some issues with transcoding the actual music files he planned on streaming, his music server was successfully up and running on a phone that would have otherwise been relegated to the junk drawer. The specific steps he took to get this working can be found on his GitHub page as well.

[David] also mentioned looking at PostmarketOS for this job which is certainly a viable option for some, but the Linux distribution for phones is only supported on a few devices. Another viable alternative for a project like this if no Raspberry Pis are available might be any of a number of Pine64 devices that might also be sitting around gathering dust, like the versatile Linux-based Pinephone.

The Goalie Mask, Reenvisioned

April 26, 2023 by 12 Comments

The goalie mask, at least the retro-styled fiberglass types from the 60s and 70s, hasn’t been used in hockey for about 50 years —  it’s instead made many more appearances in horror movies than on ice rinks. Since then, though, there’s been very little innovation surrounding the goalie mask even though there’s much more modern technology that could theoretically give them even greater visibility. [Surjan Singh] is hoping to use his engineering and hockey backgrounds to finally drive some improvements.

The “uncage” is based on Dyneema thread, a polyethylene fiber known for its strength and durability. It’s often used in applications that demand high strength with minimal weight, such as for sails or backpacking equipment. Using strands of Dyneema woven through a metal support structure is what gives this mask its high strength while also improving the visibility through it dramatically. [Surjan] has been prototyping this design extensively, as there were some issues with the fibers chafing on attachment points on the metal frame, but most of these issues have been ironed out or are being worked on currently.

In the meantime, [Surjan] has been looking for a professional-level goalie to help refine his design further and does seem to have some interest, but it doesn’t seem to have progressed past testing in the more controlled test environments yet. It’s not too far-fetched to imagine this as the future of goalie masks in professional hockey though since some innovation after 50 years of relative stagnation seems to be due. For something more accessible to those of us not currently playing in the NHL, though, you can wheel, snipe, and celly on this air hockey table instead.

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Build Your Own Bootable Emacs Environment

April 22, 2023 by 18 Comments

An old joke is that Emacs is a text editor with an operating system included, given that its extensibility and customization often goes far beyond traditional text editors. Part of its well-earned reputation comes from being built in Lisp which allows it to be expanded to do almost anything. Despite this in-joke in the community, though, you will still need an actual operating system to run it, but not much more than that.

This project uses User-Mode Linux (UML) as a foundation to load almost nothing other than an Emacs editor. UML is a virtualization technology that allows running multiple Linux kernel instances as separate virtual machines, so once the Linux environment is started and Emacs is compiled, the virtual machine can essentially boot straight into an Emacs environment. Some tools are needed outside of the Linux kernel like mount which allows the virtual file system to access the files needed to build Emacs, but as far as lightweight or minimalist Linux distributions go this one definitely gets at least an honorable mention.

While UML is virtualization software rather than a full-fledged Linux distribution, we would expect a similarly minimalist build could easily be done with something more hardware-based like Linux From Scratch. Emacs has been around for so long and had such a wide reach that it’s difficult to imagine a world without it. Even in more modern technology like browsers, knowing a little bit about Emacs can be an extremely powerful tool.

Before You Sudo Rm -rf /, Take Some Precautions

April 21, 2023 by 40 Comments

Maintaining or administering a computer system remotely is a common enough task these days, but it’s also something that can go sideways on you quickly if you aren’t careful. How many of us are guilty of executing a command, having it fail, and only then realizing that we weren’t connected to the correct computer at all? [Callan] occasionally has this issue as well, but in at least one instance, he deleted all of the contents of the wrong server by mistake. To avoid that mistake again, he uses color codes in the command line in a fairly unique way.

The solution at first seems straightforward enough. Since the terminal he’s using allows for different colors to be displayed for the user and hostname on the bash prompt, different text and background colors are used for each server. The only problem with this is that his friends also have access to these servers, and one of them is red/green colorblind, which led to another near-catastrophic mix-up. To ensure no edge cases are missed, [Callan] built a script which runs on every new server he spins up which selects two random colors, checks that they contrast well with each other, don’t create problems for the colorblind, and then applies them to the bash prompt.

For a problem most of us have had at some point or another, it’s a fairly elegant solution that helps ensure we’re sending the right commands to the right computer. This adds a layer of automation to the process and, while some color combinations do look similar, there are enough to help out most of us in some way, especially since he has released the source code on his GitHub page. For other helpful server administration tips, we’d recommend the Linux-Fu article about deploying your own dynamic DNS.

Getting The Most From Fading ThinkPads

April 21, 2023 by 40 Comments

The ThinkPad line of laptops has been widely prized not only by businesses but also by those who appreciate a high standard of hardware quality and repairability. But some think the cracks are starting to form in their reputation, as it seems that new ThinkPads are sacrificing quality for aesthetics and cost. As a result a huge modding scene has popped up around models that are a few years old like [Cal] found out when working on this X230.

At first he only made some cosmetic improvements to the laptop like replacing the worn palm rest, but quickly found himself in a rabbit hole with other upgrades like swapping out the keyboard and battery. The new keyboard is a 7-row X220 keyboard, which required modification of the connector and flashing the embedded controller with a hacked image to change the keyboard map without needing to make changes at the OS level. From there, he decided to replace the lackluster screen with a 1920×1080 matte IPS panel using an adapter board from Nitrocaster, and finished off his upgrades with a customized Coreboot BIOS for improved performance and security.

While Coreboot doesn’t remove all of the binary blobs that a bootloader like libreboot does, the latter is not compatible with more modern machines like this X230. Still, you’ll get many benefits from using Coreboot instead of the stock bootloader. For running Linux on a daily driver laptop, we appreciate all of these updates and expect that [Cal] will get plenty of years of use out of his machine. We’ve definitely seen an active modding scene for ThinkPads that were (at the time) seven years old and still going strong, so we’d expect nothing less for this one.

MRI Resolution Progresses From Millimeters To Microns

April 20, 2023 by 15 Comments

Neuroscientists have been mapping and recreating the nervous systems and brains of various animals since the microscope was invented, and have even been able to map out entire brain structures thanks to other imaging techniques with perhaps the most famous example being the 302-neuron brain of a roundworm. Studies like these advanced neuroscience considerably but even better imaging technology is needed to study more advanced neural structures like those found in a mouse or human, and this advanced MRI machine may be just the thing to help gain better understandings of these structures.

A research team led by Duke University developed this new MRI technology using an incredibly powerful 9.4 Tesla magnet and specialized gradient coils, leading to an image resolution an impressive six orders of magnitude higher than a typical MRI. The voxels in the image measure at only 5 microns compared to the millimeter-level resolution available on modern MRI machines, which can reveal microscopic details within brain tissues that were previously unattainable. This breakthrough in MRI resolution has the potential to significantly advance understanding of the neural networks found in humans by first studying neural structures in mice at this unprecedented detail.

The researchers are hopeful that this higher-powered MRI microscope will lead to new insights and translate directly into advancements healthcare, and presuming that it can be replicated, used on humans safely, and becomes affordable, we would expect it to find its way into medical centers as soon as possible. Not only that, but research into neuroscience has plenty of applications outside of healthcare too, like the aforementioned 302-neuron brain of the Caenorhabditis elegans roundworm which has been put to work in various robotics platforms to great effect.

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A RISC-V Supercluster For Very Low Cost

April 19, 2023 by 22 Comments

As ARM continues to make inroads in the personal computing space thanks to its more modern and streamlined instruction set architecture (ISA) and its reduced power demands especially compared to x86 machines, the main reason it continues to become more widespread is how easy it is to get a license to make chips using this ISA. It’s still not a fully open source instruction set, though, so if you want something even more easily accessible than ARM you’ll need to find something like these chips running the fully open-source RISC-V ISA and possibly put them to work in a custom supercluster.

[bitluni] recently acquired a large number of CH32V003 microcontrollers and managed to configure them all to work together in a cluster. The entire array is only $2 (not including all of the other components attached to the board) so a cluster of arbitrary size is potentially possible. [bitluni] built a four-layer PCB for this project with an 8-bit bus so the microcontrollers can communicate with each other. Each chip has its own ADC and I/O that are wired to a set of GPIO pins on the sides of the board. The build is rounded out with a USB interface for programming and power.

There were a few quirks to get this supercluster up and running, including some issues with the way the reset and debug pins work on these specific microcontrollers. With some bugs like this out of the way, the entire cluster is up and running, and [bitluni] hints that his design could be easily interfaced with even larger RISC-V superclusters. As for a use for this build, sometimes clusters like these are built just to build them, but since the I/O and ADCs are accessible in theory this cluster could do anything a larger microcontroller might be able to do, only at a much lower price.

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