When Pi Supply Falls Short, Thin Clients Stand Tall For Home Automation And Low Power Computing

Do you need a cheap, small computer for a low power computing project? Historically, many of us would reach straight for a Raspberry Pi, even if we didn’t absolutely need the GPIO. But with prices elevated and supplies in the dumps, [Andreas Spiess] decided that it was time to look for alternatives to now-expensive Pi’s which you can see in the video below the break.

Setting up Debian for IOTstack

Many simply use the Pi for its software ecosystem, its lower power requirements, and diminutive size. [Andreas] has searched eBay, looking for thin PC clients that can be had for as little as $10-15. A few slightly more expensive units were also chosen, and in the video some comparisons are made. How do these thin clients compare to a Pi for power consumption, computing power, and cost? The results may surprise you!

Software is another issue, since many Pi projects rely on Raspbian, a Pi-specific ARM64 Linux distribution. Since Raspbian is based on Debian, [Andreas] chose it as a basis for experimentation. He thoughtfully included such powerful software as Proxmox for virtualization, IOTstack, and Home Assistant, walking the viewer through each step of running Home Assistant on x86-64 hardware and noting the differences between the Linux distributions.

All in all, if you’ve ever considered stepping out of the Pi ecosystem and into general Linux computing, this tutorial will be an excellent starting point. Of course [Andreas] isn’t the first to bark up this tree, and we featured another thin client running Klipper for your 3D printer earlier this month. Have you found your own perfect Pi replacement in these Pi-less times? Let us know in the comments below.

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Thin Client And Smartphone Step In For 3D Printer’s Raspberry Pi And Touchscreen

It’s no secret that Raspberry Pi’s are a little hard to come by these days. Unless you had the foresight to stock up before the supply dried up — and if you did, we want to talk to you — chances are good that you’ve got a fair number of projects that use the ubiquitous SBC on indefinite hold. And maybe that’s got you thinking about alternatives to the Pi.

That’s apparently what was on [Crimson Repair]’s mind lately, the result being the discovery that an old thin client PC makes a dandy stand-in for a Raspberry Pi, at least in some cases. The video below is on the long side, true, But it’s chock full of command-by-command instructions for getting a Dell Wyse 3040, a thin client that can be found on the secondary market for $25 or so, up and running as a Klipper alternative for a 3D printer. These machines, which usually see use in point-of-sale applications and the like, sport a 1.4-GHz Intel Atom processor and a couple of gigs of RAM, and the form factor is just right for tucking into the base of an Ender 3.

Getting one up and running is a matter of getting a Debian image onto a USB key and configuring the thin client to boot from USB. After that it’s a simple matter of installing Klipper and wiring up a buck converter to power the machine. It’s not exactly rocket surgery, but why muddle through the process when someone has already been down the path ahead of you? And if you want to take it further, the second video below walks you through all the steps needed to add a touchscreen using an old Android phone. With a 3D printed bracket, the whole thing is a nicely complete printer control solution.

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More Software-Defined Radio Projects Using DragonOS

DragonOS, a Debian-based Linux distribution specifically packaged for software-defined radio functionality, roared onto the wavelengths during the beginnings of the various pandemic lockdowns last year. Since then [Aaron], the creator of the OS, has been busy adding features to the distribution as well as creating plenty of videos which show off its capabilities and also function as how-tos for people who might want to learn about software-defined radio. The latest is a video about using this software to detect radio signals in certain specified spectrums.

This build uses two  RTL-SDR devices paired with the DragonOS software suite to automatically detect active frequencies within a specified frequency range and that aslo exceed a threshold measured above the average noise floor. The video includes the setup of the software and its use in detecting these signals, but also includes setup of influxdb and Grafana which provide logging capabilities as well. Using this setup, multiple receivers either local or over the internet can then be configured to dump all the identified frequencies, powers, and time stamps into DragonOS.

[Aaron] has also been helping developers to build the SDR4space.lite application which includes GPS support, so he hopes that in a future video a user will be able to easily associate location to identified frequencies. Projects like these also serve as a reminder that getting into software-defined radio is as easy as buying a $10 USB radio receiver and configuring some free software to do anything that you can imagine like tracking ships and airplanes in real time.

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Software-Defined Radio Made Easy

Just a few decades ago, getting into hobby radio meant lots of specialty hardware, and making changes to your setup to work on various frequencies wasn’t particularly easy. Since software-defined radio (SDR) came onto the scene in an accessible way for most of us, this barrier to entry was reduced significantly and made the process of getting on the air a lot easier. It goes without saying that it does require some software, but [Aaron]’s latest project makes even getting that software extremely simple.

What he has done is created a custom Linux distribution based on Debian, called DragonOS, with the entire suite of SDR programs needed to get up and running. Out of the box, it supports RTL-SDR, HackRF and LimeSDR packages and even includes other fun tools you’ll need like Kismet. There are several video demonstrations of his distribution, including using RTL-SDR for ADS-B reception, and also shows off several custom implementations of the OS in various scenarios on his YouTube channel. The video linked below also shows how to set up the distribution in a virtual machine, so you can run this even if you don’t have a computer to dedicate to SDR.

Getting into SDR has never been easier, and the odds of having something floating around in the junk drawer that you can use to get started are pretty high. The process is exceptionally streamlined with [Aaron]’s software suite. If you’re a little short on hardware, though, there’s no better place to get started than with the classic TV-tuner-to-SDR hack from a few years back.

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Hackaday Links: November 24, 2019

It barely seems like it, but it’s been a week since the 2019 Hackaday Superconference wrapped up in sunny Pasadena. It was an amazing weekend, filled with fun, food, camaraderie, and hacks galore. For all who were there, it’ll likely take quite some time before spinning down to Earth again from the post-con high. For those who couldn’t make it, or for those who did but couldn’t squeeze in time for all those talks with everything else going on, luckily we’ve got a ton of content for you to review. Start on the Hackaday YouTube channel, where we’ve got videos already posted from most of the main stage talks. Can’t-miss talks include Chris Gammell’s RF deep-dive, Kelly Heaton’s natural electronic art, and Mohit Bhoite’s circuit sculpture overview. You’ll also want to watch The State of the Hackaday address by Editor-in-Chief Mike Szczys. More talks will be added as they’re edited, so watch that space for developments.

One of the talks we missed – and video of which appears not to be posted yet – was Adam Zeloof’s talk on thermodynamic design for your circuits. While we wait for that, here’s an interesting part that might prove useful for your next high-power design. It’s a Thermal Jumper Chip, which is essentially a ceramic SMD component that can conduct heat but not electricity. It’s intended to be used where a TO-220 case needs to be electrically isolated but thermally connected to a heatsink. Manufacturer TT Electronics has a whole line of the chips in various sizes and specs, plus a lot of other cool components like percussive igniters.

We got an interesting tip this week about a new development in the world of 3D-printing. A group from Harvard demonstrated a multinozzle extruder that can print multimaterial objects in a single pass. The work is written up in a Nature article entitled “Voxelated soft matter via multimaterial multinozzle 3D printing”, which is unfortunately paywalled, but the abstract and supplementary videos are really interesting. This appears not to be a standard hot plastic extrusion process; rather, the extruder uses elastomeric inks that cure after they’re extruded. They manage some clever tricks, including a millipede-like, vacuum-powered soft robot extruded in one pass from both soft and rigid silicone elastomers. It’s genuinely interesting stuff, and watching the multimaterial extruder head switch materials at up to 50 times per second is mesmerizing.

People really seemed to get worked up over the transit of Mercury across the face of the Sun last week, and for good reason – astronomical alignments such as these which can be seen from Earth are rare indeed, and worth taking time to see. Not everyone was in the right place at the right time with the right gear to view the transit directly, though, which is why we were glad that Justin over at The Thought Emporium did a video on leveraging online assets for space-based observations. We’ve featured a ton of hacks using SDRs and the like to intercept data from weather satellites, and while those hacks are fun and you should totally try them, Justin points out that most of these streams are readily available for free over the Internet. Clouds, lightning, forest fires and Earth changes, and yes, even the state of the Sun can all be monitored from the web.

Speaking of changes, do you know what has changed in Unix over the last 50 years? For that matter, did you know that Unix turned 50 recently? Sean Haas did after reading this article in Advent of Computing, which he shared on the tipline. The article compares a modern Debian distro to documentation from 1971 that pre-dates Unix version 1; we assume the “Dennis_v1” folder in the doc’s URL refers to none other than Dennis Ritchie himself. It turns out that Unix is remarkably well-conserved over 50 years, at least in the userspace. File system navigation and shell commands are much the same, while programming was much different. C didn’t yet exist – Dennis was busy – but there were assemblers and linkers, plus a FORTRAN compiler and an interpreter for BASIC. It’s comforting to know that if you drop into a wormhole and end up sitting in front of a PDP-11 with Three Dog Night singing “Joy to the World” on the radio in the background, you’ll at least be able to look like you belong there.

And finally, it’s nearly Sparklecon time again. Sparklecon VII will be held on January 25 and 26, 2020, at the 23b Shop hackspace in Fullerton, California. We’ve covered previous Sparkelcons and we’ve even sponsored the meetup in the past, and it looks like a blast. The organizers have put out a Call for Proposals for talks and workshops, so if you’re in the mood for some mischief, get your application going. And be quick about it – the CFP closes on December 8.

HOPE XII: A FOSS Operating System For E-Readers

Free and open source software (FOSS) was a recurring theme during many of the talks during the HOPE XII conference, which should probably come as no surprise. Hackers aren’t big fans of being monitored by faceless corporate overlords or being told what they can and cannot do on the hardware they purchased. Replacing proprietary software with FOSS alternatives is a way to put control back into the hands of the user, so naturally many of the talks pushed the idea.

In most cases that took the form of advising you to move your Windows or Mac OS computer over to a more open operating system such as GNU/Linux. Sound advice if you’re looking for software freedom, but it’s a bit quaint to limit such thinking to the desktop in 2018. We increasingly depend on mobile computing devices, and more often than not those are locked down hard with not only a closed proprietary operating system but also a “Walled Garden” style content delivery system. What’s the point of running all FOSS software at home on your desktop if you’re carrying a proprietary mobile device around?

That’s precisely the thinking that got Marc Juul interested in the possibility of bringing a FOSS operating system to e-reader devices. During his talk “Liberate Your E-book Reader with fread.ink!”, he gave examples such as Amazon’s infamous remote deletion of 1984 off of users’ Kindles as a perfect example of the sort of control these companies exert on our personal devices. Marc believes the goal should be to completely replace the operating system on these devices with a free software alternative that still retains the ability to open electronic book formats. Not only would this keep the likes of Amazon or Barnes and Noble out of our reading habits, but turn these cheap readers into more capable devices in the bargain.

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Giving Linux The Remote Boot

A lot of embedded systems are running Linux on platforms like Raspberry Pi. Since Linux is fully functional from a command line and fully network-capable, it is possible to run servers that you’ve never had physical access to.

There are a few problems, though. Sometimes you really need to reboot the box physically. You also need to be at the console to do things like totally install a new operating system. Or do you? Over on GitHub, user [marcan] has a C program and a shell script that allows you to take over a running system without using any software on the root filesystem. It starts an ssh server and you can remotely unmount the main drive, do any maintenance you want and –presumably–reboot into a new operating system.

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