$99 Pinebook Gets KDE Neon Port

August 29, 2018 by Tom Nardi 42 Comments

If you’re the kind of person who likes small and cheap Linux devices, you’re definitely alive in the perfect moment in history. It seems as if every few months we’ve got another tiny Linux board competing for our pocket change, all desperate to try to dethrone the Raspberry Pi which has already set the price bar exceptionally high (or low, as the case may be). We’ve even started to see these Linux boards work their way into appropriately cheap laptops, though so far none have really made that great of an impression.

But thanks to the efforts of Blue Systems and Pine64, the situation might be improving: they’ve worked together on a build of KDE Neon for the $99 Pinebook. The fact that they’ve gotten Plasma, KDE’s modern desktop environment, running on the rather mediocre hardware at all is an accomplishment by itself. But they’ve also set out tailor the entire system for the Pinebook, from the kernel and graphics drivers all the way up to Qt and Plasma tweaks.

In a blog post announcing the release candidate of the OS, Neon developer [Jonathan Riddell] says that these top-to-bottom improvements show that you can turn a super cheap Linux laptop into a practical computer if you’re willing to really get in there and optimize it. He also says the project has been something of a two-way street, in that improvements made for the Pinebook build have also been applied to upstream development.

The last time we looked at the Pinebook, we came away cautiously optimistic. It wasn’t great, but it was about as good as you could possibly expect given the price. If more developers are willing to go out on a limb and start optimizing their software for the device, it might become a very promising platform for low-cost mobile hacking.

Linux Fu: Modernize Your Command Line

August 29, 2018 by Al Williams 19 Comments

If you use Linux and its associated tools on the desktop or on a Raspberry Pi, or on a server, you probably have used the command line. Some people love it and some people hate it. However, many of us have been using Linux for years and sometimes Unix before that, and we tend to use the same old tried-and-true tools. [Remy Sharp] had a recent post talking about how he had created aliases to replace those old tools with great modern replacements and it is definitely worth a read.

We’ll be honest, when we first saw the post we almost skipped reading it. A lot of Linux tip posts are pretty uninteresting unless you are a total beginner. But [Remy] has a lot of really great tools and how he has them installed including bat, which is like cat but with syntax coloring (see picture above), and fzf — a command line history search on steroids. He even shows how to join fzf and bat to make a very cool file browser from the command line (see below).

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Run A Linux Terminal On Cheap E-Ink Displays

August 14, 2018 by Tom Nardi 49 Comments

If you haven’t kept up with the world of e-ink displays, here’s some good news: they are pretty cheap now. For as little as $15 you can get a small e-ink display that has good enough performance and contrast to actually do something useful. There’s only one problem: figuring out how to drive them in your project.

Tired of seeing nothing but wiring diagrams and sample code when it came to actually putting these e-ink modules to use, [Jouko Strömmer] decided to try his hand at creating a turn-key application for these gorgeous little displays. The result is PaperTTY, a Python program that allows the user to open up a fully functional Linux virtual terminal on an e-ink display.

Of course, there are some caveats. For one, this all assumes you’re using a Waveshare display (specifically their 2.13 inch HAT) connected to a Raspberry Pi over SPI. Not to say that’s the only hardware combination that will work, but it’s the only one that [Jouko] has done any testing on at this point. If you want to try to shake things up in terms of hardware, you might need to get your hands dirty.

The advantage of being able to open a Linux VT on one of these e-ink displays is pretty simple: you can run basically any piece of software you want on it. Rather than having to come up with software that specifically features support for the display, you can just use (or write) standard Linux console programs. [Jouko] mentions a number of popular programs such as vim and irssi, but you could just as easily write a Bash script to dump whatever data you like to the screen.

In the video after the break [Jouko] shows PaperTTY in action for the doubters who think these sorts of displays are no good for interactive use. The display is very crisp and readable, with no signs of flickering. Overall he says the experience is not unlike using a slow SSH connection. It might not be how we’d like to use a computer full time, but we can definitely see the potential.

With the recent progress with Kindle hacking, it seems that interest in e-ink is as high as ever. Despite what the haters might claim, it’s a useful niche tech that still holds plenty of promise.

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Python Resurrects Dot Matrix Printing

August 9, 2018 by Al Williams 54 Comments

These days a printer — especially one at home — is likely to spray ink out of nozzles. It is getting harder to find home laser printers, and earlier printer technologies such as dot matrix are almost gone from people’s homes even if you’ll still see a few printing multipart forms in some offices.

[Thomas Winningham] bought an old Commodore dot matrix printer in a fast food parking lot for $20. How hard could it be to get it working? How hard, indeed. Check out the video below to see the whole adventure. The principle behind the printer is simple enough. The head has one or two rows of pins each controlled by a solenoid. The head moves across the paper and your job — should you decide to accept it — is to make the pins push out at the right spot. An ink ribbon like a typewriter uses — oh yeah, more vanishing tech — leaves ink on the paper where it gets punched by the pin.

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Linux Fu: Scripting For Binary Files

June 29, 2018 by Al Williams 31 Comments

If you ever need to write a binary file from a traditional language like C, it isn’t all that hard to do. About the worst thing you might have to deal with is attempts to fake line endings across Windows and Linux, but there’s usually a way to turn that off if it is on by default. However, if you are using some type of scripting language, binary file support might be a bit more difficult. One answer is to use a tool like xxd or t2b (text-to-binary) to handle the details. You can find the code for t2b on GitHub including prebuilt binaries for many platforms. You should be able to install xxd from your system repository.

These tools take very different approaches. You might be familiar with tools like od or hexdump for producing readable representations of binary files. The xxd tool can actually do the same thing — although it is not as flexible. What xxd can even reverse itself so that it can rebuild a binary file from a hex dump it creates (something other tools can’t do). The t2b tool takes a much different approach. You issue commands to it that causes it to write an original hex file.

Both of these approaches have some merit. If you are editing a binary file in a scripting language, xxd makes perfect sense. You can convert the file to text, process it, and then roll it back to binary using one program. On the other hand, if you are creating a binary file from scratch, the t2b program has some advantages, too.

I decided to write a few test scripts using bash to show how it all works. These aren’t production scripts so they won’t be as hardened as they could be, but there is no reason they couldn’t be made as robust as you were willing to make them.

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E-Dermis: Feeling At Your (Prosthetic) Fingertips

June 24, 2018 by Kristina Panos No comments

When we lose a limb, the brain is really none the wiser. It continues to send signals out, but since they no longer have a destination, the person is stuck with one-way communication and a phantom-limb feeling. The fact that the brain carries on has always been promising as far as prostheses are concerned, because it means the electrical signals could potentially be used to control new limbs and digits the natural way.

A diagram of the e-dermis via *Science Robotics*.

It’s also good news for adding a sense of touch to upper-limb prostheses. Researchers at Johns Hopkins university have spent the last year testing out their concept of an e-dermis—a multi-layer approach to expanding the utility of artificial limbs that can detect the curvature and sharpness of objects.

Like real skin, the e-dermis has an outer, epidermal layer and an inner, dermal layer. Both layers use conductive and piezoresistive textiles to transmit information about tangible objects back to the peripheral nerves in the limb. E-dermis does this non-invasively through the skin using transcutaneous electrical nerve stimulation, better known as TENS. Here’s a link to the full article published in Science Robotics.

First, the researchers made a neuromorphic model of all the nerves and receptors that relay signals to the nervous system. To test the e-dermis, they used 3-D printed objects designed to be grasped between thumb and forefinger, and monitored the subject’s brain activity via EEG.

For now, the e-dermis is confined to the fingertips. Ideally, it would cover the entire prosthesis and be able to detect temperature as well as curvature. Stay tuned, because it’s next on their list.

Speaking of tunes, here’s a prosthetic arm that uses a neural network to achieve individual finger control and allows its owner to play the piano again.

Thanks for the tip, [Qes].

Linux Fu: The Great Power Of Make

June 22, 2018 by Al Williams 76 Comments

Over the years, Linux (well, the operating system that is commonly known as Linux which is the Linux kernel and the GNU tools) has become much more complicated than its Unix roots. That’s inevitable, of course. However, it means old-timers get to slowly grow into new features while new people have to learn all in one gulp. A good example of this is how software is typically built on a Linux system. Fundamentally, most projects use make — a program that tries to be smart about running compiles. This was especially important when your 100 MHz CPU connected to a very slow disk drive would take a day to build a significant piece of software. On the face of it, make is pretty simple. But today, looking at a typical makefile will give you a headache, and many projects use an abstraction over make that further obscures things.

In this article, I want to show you how simple a makefile can be. If you can build a simple makefile, you’ll find they have more uses than you might think. I’m going to focus on C, but only because that’s sort of the least common denominator. A make file can build just about anything from a shell prompt.

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