If you were to scratch any random hacker from the last 100 years, chances are pretty good you’d find an amateur radio operator just beneath the surface. Radio is the first and foremost discipline where hacking was not only welcomed, but required. If you wanted to get on the air, you sat down with some coils of wire, a few random parts — as often as not themselves homemade — and a piece of an old breadboard, and you got to work. Build it yourself or do without, and when it broke down or you wanted to change bands or add features, that was all on you too.
Like everything else, amateur radio has changed dramatically over the decades, and rolling your own radio isn’t exactly a prerequisite for entry into the ham radio club anymore. Cheap but capable handheld radios are available for a pittance, better quality radios are well within most people’s budget, and commercially available antennas have reduced the need to dabble in that particular black art. The barrier to entry for amateur radio has never been lower; you don’t even have to learn Morse anymore! So why haven’t you gotten a license?
Whatever your reason for putting off joining the club of licensed amateur radio operators, we’re going to do our best to change your mind. And to help us do that, we’ve asked Mark Hughes (KE6WOB) and Beau Ambur (K6EAU) to swing by the Chat and share their experiences with getting on the air. Both are relatively recent licensees, and they’ll do their best to answer your questions about getting on the air for the first time, to get on your way to building that first radio.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
Generating videos for projects can be difficult. Not only do you have to create the thing, but you film the process and cut it together in a story that a viewer can follow. Explaining complex topics to the viewer often involves a whiteboard of some sort, but as we all know, it’s not always a perfect solution. [Jacob] was working on a video game and making videos to document the progress and built a tool called Motion Canvas to help visualize topics like custom shaders. A few months ago, he decided to release it as an open source project.
Since then, it has seen quite a few forks and GitHub forks with a lively showcase on the community Discord. Looking at the docs, it is pretty easy to see why. The interface allows you to write procedural animations using the async semantics of TypeScript while still offering the GUI interface we expect from our video editors. In particular, the signal system allows dependencies to be defined between values. The system runs in Node, and the GUI runs in your browser locally while you edit the files in your terminal/notepad/IDE. CSS and Flexbox are available as the video is rendered to a web canvas and then compiled into a video via FFMPEG. The documentation is quite extensive, and it’s a great example of a tool someone built to fit a need they had going on to become something a little more fantastic.
The future, as seen in the popular culture of half a century or more ago, was usually depicted as quite rosy. Technology would have rendered every possible convenience at our fingertips, and we’d all live in futuristic automated homes — no doubt while wearing silver clothing and dreaming about our next vacation on Mars.
Of course, it’s not quite worked out this way. A family from 1965 whisked here in a time machine would miss a few things such as a printed newspaper, the landline telephone, or receiving a handwritten letter; they would probably marvel at the possibilities of the Internet, but they’d recognise most of the familiar things around us. We still sit on a sofa in front of a television for relaxation even if the TV is now a large LCD that plays a streaming service, we still drive cars to the supermarket, and we still cook our food much the way they did. George Jetson has not yet even entered the building.
The Future is Here, and it Responds to “Alexa”
“Alexa, why haven’t you been a commercial success?” Gregory Varnum, CC BY-SA 4.0
There’s one aspect of the Jetsons future that has begun to happen though. It’s not the futuristic automation of projects such as Disneyland’s Monsanto house Of The Future, but instead it’s our current stuttering home automation efforts. We’re not having domestic robots in pinnies hand us rolled-up newspapers, but we’re installing smart lightbulbs and thermostats, and we’re voice-controlling them through a variety of home hub devices. The future is here, and it responds to “Alexa”.
But for all the success that Alexa and other devices like it have had in conquering the living rooms of gadget fans, they’ve done a poor job of generating a profit. It was supposed to be a gateway into Amazon services alongside their Fire devices, a convenient household companion that would help find all those little things for sale on Amazon’s website, and of course, enable you to buy them. Then, Alexa was supposed to move beyond your Echo and into other devices, as your appliances could come pre-equipped with Alexa-on-a-chip. Your microwave oven would no longer have a dial on the front, instead you would talk to it, it would recognise the food you’d brought from Amazon, and order more for you.
Instead of all that, Alexa has become an interface for connected home hardware, a way to turn on the light, view your Ring doorbell on models with screens, catch the weather forecast, and listen to music. It’s a novelty timepiece with that pod bay doors joke built-in, and worse that that for the retailer it remains by its very nature unseen. Amazon have got their shopping cart into your living room, but you’re not using it and it hardly reminds you that it’s part of the Amazon empire at all.
But it wasn’t supposed to be that way. The idea was that you might look up from your work and say “Alexa, order me a six-pack of beer!”, and while it might not come immediately, your six-pack would duly arrive. It was supposed to be a friendly gateway to commerce on the website that has everything, and now they can’t even persuade enough people to give it a celebrity voice for a few bucks.
The Gadget You Love to Hate
In the first few days after the Echo’s UK launch, a member of my hackerspace installed his one in the space. He soon became exasperated as members learned that “Alexa, add butt plug to my wish list” would do just that. But it was in that joke we could see the problem with the whole idea of Alexa as an interface for commerce. He had locked down all purchasing options, but as it turns out, many people in San Diego hadn’t done the same thing. As the stories rolled in of kids spending hundreds of their parents’ hard-earned on toys, it would be a foolhardy owner who would leave left purchasing enabled. Worse still, while the public remained largely in ignorance the potential of the device for data gathering and unauthorized access hadn’t evaded researchers. It’s fair to say that our community has loved the idea of a device like the Echo, but many of us wouldn’t let one into our own homes under any circumstances.
So Alexa hasn’t been a success, but conversely it’s been a huge sales success in itself. The devices have sold like hot cakes, but since they’ve been sold at close to cost, they haven’t been the commercial bonanza they might have hoped for. But what can be learned from this, other than that the world isn’t ready for a voice activated shopping trolley?
Sadly for most Alexa users it seems that a device piping your actions back to a large company’s data centres is not enough of a concern for them. It’s an easy prediction that Alexa and other services like it will continue to evolve, with inevitable AI pixie dust sprinked on them. A bet could be on the killer app being not a personal assistant but a virtual friend with some connections across a group of people, perhaps a family or a group of friends. In due course we’ll also see locally hosted and open source equivalents appearing on yet-to-be-released hardware that will condense what takes a data centre of today’s GPUs into a single board computer. It’s not often that our community rejoices in being late to a technological party, but I for one want an Alexa equivalent that I control rather than one that invades my privacy for a third party.
The “caterpillar drive” in The Hunt for Red October allowed the sub to travel virtually undetected through the ocean, but real examples of magnetohydrodynamic drives (MHDs) are rare. The US Navy’s recently announced Principles of Undersea Magnetohydrodynamic Pumps (PUMP) intends to jump-start the technology for a new era.
Dating back to the 1960s, research on MHDs has been stymied by lower efficiencies when compared with driving a propeller from the same power source. In 1992 the Japanese Yamato-1 prototype, pictured at the top of the page, was able to hit a blistering 6.6 knots (that’s 12 kph or 7.4 mph for you landlubbers) with a 4 Tesla liquid helium-cooled MHD. Recent advances courtesy of fusion research have resulted in magnets capable of generating fields up to 20 Telsa, which should provide a considerable performance boost.
The new PUMP program will endeavor to find solutions for more robust electrode materials that can survive the high currents, magnetic fields, and seawater in a marine environment. If successful, ships using the technology would be both sneakier and more environmentally friendly. While you just missed the Proposers Day, there is more information about getting involved in the project here.
Having acquired some piece of old electronic equipment, be it a computer, radio, or some test gear, the temptation is there to plug it in as soon as you’ve lugged it into the ‘shop. Don’t be so hasty. Those power supplies and analog circuits often have a number of old aluminium electrolytic capacitors of unknown condition, and bad things can happen if they suddenly get powered back up again. After a visual inspection, to remove and replace any with obvious signs of leakage and corrosion, those remaining may still not be up to their job, with the oxide layers damaged over time when sat idle, they can exhibit lower than spec capacitance, voltage rating or even be a dead short circuit. [TechTangents] presents for us a guide to detecting and reforming these suspect capacitors to hopefully bring them, safely, back to service once more.
Capacitor failure modes are plentiful
When manufactured, the capacitors are slowly brought up to operating voltage, before final encapsulation, which allows the thin oxide layer to form on the anode contact plate, this is an electrically driven chemical process whereby a portion of the electrolyte is decomposed to provide the needed oxygen ions. When operating normally, with a DC bias applied to the plates, this oxidation process — referred to as ‘self-healing’ — continues slowly, maintaining the integrity of the oxide film, and slowly consuming the electrolyte, which will eventually run dry and be unable to sustain the insulating oxide layer.
If left to sit un-powered for too long, the anodic oxide layer will decay, resulting in reduced operating voltage. When powered up, the reforming process will restart, but this will be in an uncontrolled environment, resulting in a lot of excess heat and gases being vented. It all depends on how thin the oxide layer got and if holes have started to form. That is, if there is any electrolyte left to react – it may already be far too late to rescue.
If the oxide layer is sufficiently depleted, the capacitor will start to conduct, with a resultant self-heating and runaway thermal decomposition. They can explode violently, which is why there are score marks at the top of the can to act as a weak point, where the contents can burst through. A bit like that ‘egg’ scene in Aliens!
Yucky leaky capacitor. Replace these! and clean-up that conductive goo too.
The ‘safe’ way to reform old capacitors is to physically remove them from the equipment, and apply a low, controlled voltage below the rated value to keep the bias current at a low value, perhaps just 2 mA. Slowly, the voltage can be increased to push the current back up to the initial forming level, so long as the current doesn’t go too high, and the temperature is within sensible bounds. The process ends when the applied voltage is at the rated value and the current has dropped off to low leakage values.
A word of warning though, as the ESR of the reformed caps could be a little higher than design, which will result in higher operating temperature and potentially increased ripple current in power supply applications.
If you want to start a heated discussion in 3D printing circles, ask people about the requirements to print safely. Is ABS safe to print without ventilation? Can you drink out of a PLA cup? How nasty is that photo resin if you spill it on yourself? If you are at home, it’s more or less up to you. But if you are building a shared hackerspace, a corporate workstation, or a classroom, these questions might come up, and now, the UL has your answer. The UL200B document is aimed at 3D printers in “institutions of higher education,” but we imagine what’s good for the university is good for us, too.
The 45-page document isn’t an easy read. It does cover both “material extrusion” and “vat photopolymerization” technology. In fact, they identify seven “most common” processes ranging from powder bed fusion, energy deposition, and more. The work results from a UL task force with participants from Harvard, Princeton, and Carnegie-Mellon. We were surprised there didn’t seem to be any industry representation, but maybe that was on purpose.
With extrusion printing — what we’d call FDM — the focus seems to be on ultra-fine particles and volatile organic compounds (VOCs). However, the level of VOCs rose up to six times with resin printers when compared to FDM. Filters helped with ABS, nylon, and ASA, and polycarbonate/ABS. The paper does acknowledge that PLA is probably safer, although it is quick to point out that PLA with additives may not be as safe as plain PLA. If you want a quick summary, check out Table 2, starting on page 23.
The rest of the document is about creating a safety plan for all the printers that might be on a college campus — that might not be as interesting. However, you’ll want to skip forward to the appendix section. It has some data about relevant industrial standards and other data.
This is a great step in analyzing the risks of 3D printing. Of course, laser printers and copiers also spew micro-particles, and we seem to have survived those for a number of decades. Still, more data is good — you should be informed to make decisions about your health and safety. We didn’t see much in the document that covered food safety, something we’ve talked about before. If you want to monitor your VOC exposure, we got you.
Characterizing the aerodynamic performance of a vehicle usually requires a wind tunnel since it’s difficult to control all variables when actually driving. Unless you had some kind of perfectly straight, environmentally controlled, and precision-graded section of road, anyway. Turns out the Catesby Tunnel in the UK meets those requirements exactly, and [Tom Scott] recently got to take a tour of it.
The 2.7 kilometer (1.7 mile) long tunnel was constructed as a railway tunnel between 1895 and 1897, thanks to the estate owner objecting to the idea of “unsightly trains” crossing his property. The tunnel’s construction was precise even by modern standards, deviating only 3 mm from being perfectly straight along its entire length. It lay abandoned for many years until it was paved and converted into a test facility, opening in 2021.
To measure the speed without the luxury of GPS reception, a high-speed camera mounted inside a vehicle detects reflective tags mounted every 5 m along the tunnel’s wall. This provides accurate speed measurement down to 0.001 km/h. A pair of turntables are installed at the ends of the tunnel to avoid an Austin Powers multi-point turn (apparently that’s the technical term) when turning around inside the confined space.
Due to the overhead soil and sealed ends, the temperature in the tunnel only varies by 1 – 2 °C year round. This controlled environment makes the tunnel perfect for coastdown tests, where a vehicle accelerates to a designated speed and then is put into neutral and allowed to coast. By measuring the loss of speed across multiple runs, it’s possible to calculate the aerodynamic drag and friction on the wheels. Thanks to the repeatable nature of the tests, it was even possible to calculate the aerodynamic losses caused by [Tom]’s cameras mounted to the outside of the vehicle.
The Catesby Tunnel is an excellent example of repurposing old infrastructure for modern use. Some other examples we’ve seen include using coal mines and gold mines for geothermal energy.
Whatever your reason for putting off joining the club of licensed amateur radio operators, we’re going to do our best to change your mind. And to help us do that, we’ve asked Mark Hughes (KE6WOB) and Beau Ambur (K6EAU) to swing by the Chat and share their experiences with getting on the air. Both are relatively recent licensees, and they’ll do their best to answer your questions about getting on the air for the first time, to get on your way to building that first radio.
