Hackaday Links Column Banner

Hackaday Links: April 5, 2020

Git is powerful, but with great power comes the ability to really bork things up. When you find yourself looking at an inscrutable error message after an ill-advised late-night commit, it can be a maximum pucker-factor moment, and keeping a clear enough head to fix the problem can be challenging. A little proactive social engineering may be in order, which is why Jonathan Bisson wrote git-undo, a simple shell script that displays the most common un-borking commands he’s likely to need. There are other ways to prompt yourself through Git emergencies, like Oh Shit, Git (or for the scatologically sensitive, Dangit Git), but git-undo has the advantage of working without an Internet connection.

Suddenly find yourself with a bunch of time on your hands and nothing to challenge your skills? Why not try to write a program in a single Tweet? The brainchild of Dominic Pajak, the BBC Micro Bot Twitter account accepts tweets and attempts to run them as BASIC programs on a BBC Microcomputer emulator, replying with the results of the program. It would seem that 280 characters would make it difficult to do anything interesting, but check out some of the results. Most are graphic displays, some animated, and with an unsurprising number of nods to 1980s pop culture. Some are truly impressive, though, like Conway’s Game of Life written by none other than Eben Upton.

The COVID-19 pandemic is causing all sorts of cultural shifts, but we didn’t expect to see much change in the culture of a community that’s been notoriously resistant to change for over a century: amateur radio. One of the most basic facts of life in the amateur radio world is that you need a license to participate, with governments regulating the process. But as a response to the pandemic, Spain has temporarily lifted licensing requirements for amateur radio operators. Normally, an unlicensed person is only allowed to operate on amateur bands under the direct supervision of a licensed amateur. The rules change allows unlicensed operators to use a station without supervision and is intended to give schoolchildren trapped at home an educational experience. In another change, some countries are allowing special callsign suffixes, like “STAYHOME,” to raise awareness during the pandemic. And the boom in interest in amateur radio since the pandemic started is remarkable; unfortunately, finding a way to take your test in a socially distant world is quite a trick. Our friend Josh Nass (KI6NAZ) has some thoughts about testing under these conditions that you might find interesting.

And finally, life goes on during all this societal disruption, and every new life deserves to be celebrated. And when Lauren Devinck made her appearance last month, her proud parents decided to send out unique birth announcement cards with a printed circuit board feature. The board is decorative, not functional, but adds a distinctive look to the card. The process of getting the boards printed was non-trivial; it turns out that free-form script won’t pass most design rule tests, and that panelizing them required making some compromises. We think the finished product is classy, but can’t help but think that a functional board would have really made a statement. Regardless, we welcome Lauren and congratulate her proud parents.

Hackaday Links Column Banner

Hackaday Links: March 22, 2020

Within the span of just two months, our world of unimaginable plenty and ready access to goods manufactured across the globe has been transformed into one where the bare essentials of life are hard to find at any price. The people on the frontline of the battle against COVID-19 are suffering supply chain pinches too, often at great risk to their health. Lack of proper personal protective equipment (PPE), especially face masks, is an acute problem, and the shortage will only exacerbate the problem as healthcare workers go down for the count. Factories are gearing up to make more masks, but in the meantime, the maker and hacker community can pitch in. FreeSewing, an open-source repository of sewing patterns, has a pattern for a simple face mask called the Fu that can be made quickly by an experienced threadworker. Efficacy of the masks made with that pattern will vary based on the materials used, obviously; a slightly less ad hoc effort is the 100 Million Mask Challenge, where volunteers are given a pattern and enough lab-tested materials to make 100 face masks. If you know how to sew, getting involved might make a difference.

As people around the world wrap their heads around the new normal of social distancing and the loss of human contact, there’s been an understandable spike in interest in amateur radio. QRZ.com reports that the FCC has recorded an uptick in the number of amateur radio licenses issued since the COVID-19 outbreak, and license test prep site HamRadioPrep.com has been swamped by new users seeking to prepare for taking the test. As we’ve discussed, the barrier for entry to ham radio is normally very low, both in terms of getting your license and getting the minimal equipment needed to get on the air. One hurdle aspiring hams might face is the cancellation of so-called VE testing, where Volunteer Examiners administer the written tests needed for each license class. Finding a face-to-face VE testing session now might be hard, but the VEs are likely to find a way to adapt. After all, hams were social distancing before social distancing was cool.

The list of public events that have been postponed or outright canceled by this pandemic is long indeed, with pretty much everything expected to draw more than a handful of people put into limbo. The hacking world is not immune, of course, with many high-profile events scuttled. But we hackers are a resourceful bunch, and the 10th annual Open Source Hardware Summit managed to go off on schedule as a virtual meeting last week. You can watch the nearly eight-hour livestream while you’re self-isolating. We’re confident that other conferences will go virtual in the near-term too rather than cancel outright.

And finally, if you’re sick of pandemic news and just want some escapist engineering eye candy, you could do worse than checking out what it takes to make a DSLR camera waterproof. We’ve honestly always numbered cameras as among the very least waterproof devices, but it turns out that photojournalists and filmmakers are pretty rough on their gear and expect it to keep working even so. The story here focuses (sorry) on Olympus cameras and lenses, which you’ll note that Takasu-san only ever refers to as “splash-proof”, and the complex system of O-rings and seals needed to keep water away from their innards. For our money, the best part was learning that lenses that have to change their internal volume, like zoom lenses, need to be vented so that air can move in and out. The engineering needed to keep water out of a vented system like that is pretty impressive.

The $50 Ham: Getting Your Ticket Punched

Today we start a new series dedicated to amateur radio for cheapskates. Ham radio has a reputation as a “rich old guy” hobby, a reputation that it probably deserves to some degree. Pick up a glossy catalog from DX Engineering or cruise their website, and you’ll see that getting into the latest and greatest gear is not an exercise for the financially challenged. And thus the image persists of the recent retiree, long past the expense and time required to raise a family and suddenly with time on his hands, gleefully adding just one more piece of expensive gear to an already well-appointed ham shack to “chew the rag” with his “OMs”.

Not a $50 ham. W9EVT’s shack. Source: QRZ.com

As I pointed out a few years back in “My Beef With Ham Radio”, I’m an inactive ham. My main reason for not practicing is that I’m not a fan of talking to strangers, but there’s a financial component to my reticence as well – it’s hard to spend a lot of money on gear when you don’t have a lot to talk about. I suspect that there are a lot of would-be hams out there who are turned off from the hobby by its perceived expense, and perhaps a few like me who are on the mic-shy side.

This series is aimed at dispelling the myth that one needs buckets of money to be a ham, and that jawboning is the only thing one does on the air. Each installment will feature a project that will move you further along your ham journey that can be completed for no more than $50 or so. Wherever possible, I’ll be building the project or testing the activity myself so I can pursue my own goal of actually using my license for a change.

Continue reading “The $50 Ham: Getting Your Ticket Punched”

GPL Violations Cost Creality A US Distributor

One of the core tenets of free and open source software licenses is that you’re being provided source code for a project with the hope that you’ll “pay it forward” if and when you utilize that code. In fact some licenses, such as the GNU Public License (GPL), require that you keep the source code for subsequent spin-offs or forks open. These are known as viral licenses, and the hope is that they will help spread the use of open source as derivative works can’t turn around and refuse to release their source code.

Unfortunately, not everyone plays by the rules. In a recent post on their blog, Printed Solid has announced they are ending their relationship with Chinese manufacturer Creality, best known for their popular CR-10 printer. Creality produces a number of printers which make use of Marlin, a GPLv3 licensed firmware that runs (in some form or another) a large majority of desktop 3D printers. But as explained in the blog post, Printed Solid has grown tired with the manufacturer’s back and forth promises to comply with the viral aspects of the GPL license.

Rather than helping to support a company they believe is violating the trust of the open source community, they have decided to mark down their existing stock of Creality printers to the point they will be selling them at a loss until they run out. In addition, for each Creality printer that is sold Printed Solid has promised to make a $50 USD donation to the development of Marlin saying: “if Creality won’t support Marlin development then we will.”

As is often the case when tempers are high and agreements break down, Printed Solid has also pulled back the curtain a bit as to the relationship they have had thus far with the manufacturer. According to the blog post, Printed Solid claims that some models of Creality printers have had a 100% fault rate, and that the company needed to repair and tweak the machines before sending them out to customers. The not so subtle implication being that Creality printers have been benefiting from the work Printed Solid has been doing on their hardware, and that purchasing a unit direct from the manufacturer could be a dicey proposition.

We’ve previously covered an issue with Creality’s CR-10S printer that required the end-user to replace an SMD capacitor just to get reliable results out of the machine, and of course we’ve talked of the extra work that’s often required when wrangling a low-end Chinese printer. It’s even more disheartening when you realize cheap machines sold by shady manufacturers are pushing open source manufacturers out of business.

My Beef With Ham Radio

My amateur radio journey began back in the mid-1970s. I was about 12 at the time, with an interest in electronics that baffled my parents. With little to guide me and fear for my life as I routinely explored the innards of the TVs and radios in the house, they turned to the kindly older gentleman across the street from us, Mr. Brown. He had the traditional calling card of the suburban ham — a gigantic beam antenna on a 60′ mast in the backyard – so they figured he could act as a mentor to me.

Mr. Brown taught me a lot about electronics, and very nearly got me far enough along to take the test for my Novice class license. But I lost interest, probably because I was an adolescent male and didn’t figure a ham ticket would improve my chances with the young ladies. My ham ambitions remained well below the surface as life happened over the next 40 or so years. But as my circumstances changed, the idea of working the airwaves resurfaced, and in 2015 I finally took the plunge and earned my General class license.

The next part of my ham story is all-too-familiar these days: I haven’t done a damn thing with my license. Oh, sure, I bought a couple of Baofeng and Wouxun handy-talkies and lurked on the local repeaters. I even bought a good, solid HF rig and built some antennas, but I’ve made a grand total of one QSO — a brief chat with a ham in Texas from my old home in Connecticut on the 10-meter band. That’s it.

Continue reading “My Beef With Ham Radio”

Get Your Amateur Radio License Already!

We run a lot of posts on amateur radio here at Hackaday, and a majority of our writers and editors* are licensed hams. Why? Because playing around with radio electronics is fun, and because having a license makes a lot more experimentation legal. (*We’re sure you have good reasons for slacking, Szczys.)

So let’s say that you want to get your “ticket” (and you live in the USA). It’s easy: just study for an exam or two, and take them. How to study? We’re glad you asked, because we just found this incredibly long video that’ll prep you for the exam.

swr_powerAt six and a half hours, we’ll admit that we haven’t watched the whole thing, but what we did see looks great. Admittedly, we were a little bit unnerved by [John (KD65CY)]’s overdone enthusiasm. But the content is fundamental, broad-ranging, and relevant. Heck, even a bit entertaining.

Even if you’re not interested in taking the exam, but are just interested in some radio basics, it’s worth looking. If you give it a shot, and like what you see, let us know in the comments what times stamps you found interesting.

The other “secret” about the amateur radio exams is that all of the questions and their answers are drawn from a publicly available pool of questions. This means that you can just cram the right answers, pass the exam, and you’ll have your grey cells back good as new in no time. To help you along your path, here are all the current Technician questions with only the correct answer for each. (And here is the Python script that generated them.) Read through this, take a couple of practice exams, and you’ll be ready to go.

In our experience, the Technician exam is easy enough that it’s probably worth your while to study up for the General exam as well. You have to take the former before the latter, but there’s nothing stopping you from taking them all in one sitting. (General gets you a lot more international shortwave frequencies, so it’s at least worth a shot.)

But don’t let that slow you down. Just getting the Tech license is easily worth studying up for a couple of hours or so. You have no excuses now. Go do it!

Continue reading “Get Your Amateur Radio License Already!”

RPiTX Turns Rasberry Pi Into Versatile Radio Transmitter

Since the discovery that some USB TV tuner dongles could be used to monitor radio waves across a huge amount of spectrum, the software-defined radio world has exploded with interest. The one limiting factor, though, has been that the dongles can only receive signals; they can’t transmit them. [Evariste Okcestbon, F5OEO] (if that is his real name! Ok c’est bon = Ok this is good) has written some software that will get you transmitting using SDR with only a Raspberry Pi and a wire.

There have been projects in the past that use a Pi to broadcast radio (PiFM), but this new software (RPiTX) takes it a couple steps further. Using just an appropriately-sized wire connected to one of the GPIO pins, the Raspberry Pi is capable of broadcasting using FM, AM, SSB, SSTV, or FSQ signals. This greatly increases the potential of this simple computer-turned-transmitter and anyone should be able to get a lot of use out of it. In the video demo below the break, [Evariste] records a wireless doorbell signal and then re-transmits it using just the Rasbperry Pi.

The RPiTX code is available on GitHub if you want to try it out. And it should go without saying that you will most likely need an amateur radio license of some sort to use most of these features, depending on your locale. If you don’t have a ham radio license yet, you don’t need one to listen if you want to get started in the world of SDR. But a ham license isn’t hard to get and at this point it shouldn’t take much convincing for you to get transmitting.

Continue reading “RPiTX Turns Rasberry Pi Into Versatile Radio Transmitter”