Pack Your Bags – Systemd Is Taking You To A New Home

Home directories have been a fundamental part on any Unixy system since day one. They’re such a basic element, we usually don’t give them much thought. And why would we? From a low level point of view, whatever location $HOME is pointing to, is a directory just like any other of the countless ones you will find on the system — apart from maybe being located on its own disk partition. Home directories are so unspectacular in their nature, it wouldn’t usually cross anyone’s mind to even consider to change anything about them. And then there’s Lennart Poettering.

In case you’re not familiar with the name, he is the main developer behind the systemd init system, which has nowadays been adopted by the majority of Linux distributions as replacement for its oldschool, Unix-style init-system predecessors, essentially changing everything we knew about the system boot process. Not only did this change personally insult every single Perl-loving, Ken-Thompson-action-figure-owning grey beard, it engendered contempt towards systemd and Lennart himself that approaches Nickelback level. At this point, it probably doesn’t matter anymore what he does next, haters gonna hate. So who better than him to disrupt everything we know about home directories? Where you _live_?

Although, home directories are just one part of the equation that his latest creation — the systemd-homed project — is going to make people hate him even more tackle. The big picture is really more about the whole concept of user management as we know it, which sounds bold and scary, but which in its current state is also a lot more flawed than we might realize. So let’s have a look at what it’s all about, the motivation behind homed, the problems it’s going to both solve and raise, and how it’s maybe time to leave some outdated philosophies behind us.

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What’s In A Name? Tales Of Python, Perl, And The GIMP

In the older days of open source software, major projects tended to have their Benevolent Dictators For Life who made all the final decisions, and some mature projects still operate that way. Guido van Rossum famously called his language “Python” because he liked the British comics of the same name. That’s the sort of thing that only a single developer can get away with.

However, in these modern times of GitHub, GitLab, and other collaboration platforms, community-driven decision making has become a more and more common phenomenon, shifting software development towards democracy. People begin to think of themselves as “Python programmers” or “GIMP users” and the name of the project fuses irrevocably with their identity.

What happens when software projects fork, develop apart, or otherwise change significantly? Obviously, to prevent confusion, they get a new name, and all of those “Perl Monks” need to become “Raku Monks”.  Needless to say, what should be a trivial detail — what we’ve all decided to call this pile of ones and zeros or language constructs — can become a big deal. Don’t believe us? Here are the stories of renaming Python, Perl, and the GIMP.

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Broken HP-48 Calculator Reborn As Bluetooth Keyboard

Considering their hardware specification, graphing calculators surely feel like an anachronism in 2019. There are plenty of apps and other software available for that nowadays, and despite all preaching by our teachers, we actually do carry calculators with us every day. On the other hand, never underestimate the power of muscle memory when using physical knobs and buttons instead of touch screen or mouse input. [epostkastl] combined the best of both worlds and turned his broken HP-48 into a Bluetooth LE keyboard to get the real feel with its emulated counterpart.

Initially implemented as USB device, [epostkastl] opted for a wireless version this time, and connected an nRF52 based Adafruit Feather board to the HP-48’s conveniently exposed button matrix pins. For the software emulation side, he uses the Emu48, an open source HP calculator emulator for Windows and Android. The great thing about Emu84 is that it supports fully customizable mappings of regular keyboard events to the emulated buttons, so you can easily map, say, the cosine button to the [C] key. The rest is straight forward: scanning the button matrix detects button presses, maps them to a key event, and sends it as a BLE HID event to the receiving side running Emu84.

As this turns [epostkastl]’s HP-48 essentially into a regular wireless keyboard in a compact package — albeit with a layout that outshines every QWERTY vs Dvorak debate. It can of course also find alternative use cases, for examples as media center remote control, or a shortcut keyboard. After all, we’ve seen the latter one built as stomp boxes and from finger training devices before, so why not a calculator?

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660 FPS Raspberry Pi Video Captures The Moment In Extreme Slo-Mo

Filming in slow-motion has long become a standard feature on the higher end of the smartphone spectrum, and can turn the most trivial physical activity into a majestic action shot to share on social media. It also unveils some little wonders of nature that are otherwise hidden to our eyes: the formation of a lightning flash during a thunderstorm, a hummingbird flapping its wings, or an avocado reaching that perfect moment of ripeness. Altogether, it’s a fun way of recording videos, and as [Robert Elder] shows, something you can do with a few dollars worth of Raspberry Pi equipment at a whopping rate of 660 FPS, if you can live with some limitations.

Taking the classic 24 FPS, this will turn a one-second video into a nearly half-minute long slo-mo-fest. To achieve such a frame rate in the first place, [Robert] uses [Hermann-SW]’s modified version of raspiraw to get raw image data straight from the camera sensor to the Pi’s memory, leaving all the heavy lifting of processing it into an actual video for after all the frames are retrieved. RAM size is of course one limiting factor for recording length, but memory bandwidth is the bigger problem, restricting the resolution to 64×640 pixels on the cheaper $6 camera model he uses. Yes, sixty-four pixels height — but hey, look at that super wide-screen aspect ratio!

While you won’t get the highest quality out of this, it’s still an exciting and inexpensive way to play around with slow motion. You can always step up your game though, and have a look at this DIY high-speed camera instead. And well, here’s one mounted on a lawnmower blade destroying anything but a printer.

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C++20 Is Feature Complete; Here’s What Changes Are Coming

If you have an opinion about C++, chances are you either love it for its extensiveness and versatility, or you hate it for its bloated complexity and would rather stick to alternative languages on both sides of the spectrum. Either way, here’s your chance to form a new opinion about the language. The C++ standard committee has recently gathered to work on finalizing the language standard’s newest revision, C++20, deciding on all the new features that will come to C++’s next major release.

After C++17, this will be the sixth revision of the C++ standard, and the language has come a long way from its “being a superset of C” times. Frankly, when it comes to loving or hating the language, I haven’t fully made up my own mind about it yet. My biggest issue with it is that “programming in C++” can just mean so many different things nowadays, from a trivial “C with classes” style to writing code that will make Perl look like prose. C++ has become such a feature-rich and downright overwhelming language over all these years, and with all the additions coming with C++20, things won’t get easier. Although, they also won’t get harder. Well, at least not necessarily. I guess? Well, it’s complex, but that’s simply the nature of the language.

Anyway, the list of new features is long, combining all the specification proposals is even longer, and each and every one of these additions could fill its own, full-blown article. But to get a rough idea about what’s going to come to C++ next year, let’s have a condensed look at some of these major new features, changes, and additions that will await us in C++20. From better type checking and compiler errors messages to Python-like string handling and plans to replace the #include system, there’s a lot at play here!

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Weather Station Can Rock You Like A Hurricane

People love to talk about the weather. It’s the perfect small talk, whether you’re trying to start a conversation or keep one going by avoiding an awkward silence. In the same fashion, weather stations are an ideal starting point for any sort of sensor-related project ideas. You get to familiarizing yourself with communication buses, ADCs, general data acquisition, and you learn a lot in figuring out how to visualize it all.

What if your weather station didn’t visualize anything? [OttoNL] is answering that question with a MIDI-generating Weather Station that uses the mood of the music to convey the condition of the elements outside.

Using an ESP8266 programmed via the Arduino IDE, [OttoNL] hooked up a light dependent resistor, a rain sensor, and the all-round workhorse BME280 for temperature, barometric pressure, and humidity to it. Reading the sensors, the ESP will generate MIDI notes that are sent to a connected synthesizer, with each sensor influencing a different aspect of the generated MIDI signals. A sadder, slow tune will play during rain and a fast upbeat one during sunshine. While it doesn’t use the ESP’s WiFi functionality at all at this point, a future version could easily retrieve some weather forecast data from the internet and add it into the mix as well.

Connect this to your alarm clock, and you can start your day off in the appropriate mood. You can even customize your breakfast toast to really immerse your morning routine in abstract weather cues.

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Raspberry Pi Catches The Early Bird

If you live in an area with high bird activity, setting up a bird feeder and watching some hungry little fellows visit you can be a nice and relaxing pastime. Throw in a Raspberry Pi with some sensors and it can also be the beginning of your next IoT project, as it was the case for [sbkirby] with his Bird Feeder Monitor project.

To track the arrival and departure times of his avian visitors, [sbkirby] attached a set of capacitive touch sensors to each side of his bird feeder, and hooked them up to a Raspberry Pi Zero W via a CAP1188 breakout board. The data is published via MQTT to another Raspberry Pi that serves as backend and stores the data, as well as to an optional additional camera-equipped Pi that will take a picture of each guest along the way. Taking into account that precipitation might affect the sensor readings, he also checks the current weather situation to re-calibrate the sensors if necessary, and also to observe a change in the birds’ presence and eating behavior based on weather conditions.

It seems that sensor-based animal feeding will always serve as inspiration for some new projects, whether feeding the animal itself is the goal, like most recently this fish feeder has shown, or whether the eating behavior is monitored and used for further research such as this squirrel-based weather forecast system.