The Use and Abuse Of CT Scanners

David Mills is as a research scientist at the cutting edge of medical imaging. His work doesn’t involve the scanners you might find yourself being thrust into in a hospital should you be unfortunate enough to injure yourself. He’s working with a higher grade of equipment, he pushes the boundaries of the art with much smaller, very high resolution CT scanners for research at a university dental school.

He’s also a friend of Hackaday and we were excited for his talk on interesting uses for CT scanners at EMF Camp this summer. David takes us into that world with history of these tools, a few examples of teeth and bone scans, and then delves into some of the more unusual applications to which his very specialist equipment has been applied. Join me after the break as we cover the lesser known ways to put x-ray technology to work.

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Linux, Without The Git Factor

Linux started as a student project in the 1990s, the creation of Linus Torvalds. He has attained celebrity status while steering his creation through the decades, but along the way he has also attracted a different reputation within the Linux and software community. He is famous for his outbursts and rants, some of which become rather personal, and it is not difficult at all to find kernel developers or would-be kernel developers who have turned their backs on the project as a result.

It’s very refreshing indeed then to read an update from [Linus] as part of his regular communications, in which he admits that he has an issue, and says that he is taking the time to seek help for it. There is an accompanying update to the kernel maintenance code of conduct, which suggests that this is likely to mark a sea-change in that environment, as well as we hope salvage that aspect of [Linus]’ reputation.

“My flippant attacks in emails have been both unprofessional and uncalled for. Especially at times when I made it personal. In my quest for a better patch, this made sense to me. I know now this was not OK and I am truly sorry.”

The Hackaday community has a much greater than average proportion of Linux users among its readership. Even those readers who use a desktop OS with BSD, Windows, or other kernels will almost certainly have a Linux kernel somewhere, whether it’s in their phone, their set-top-box, their children’s toys, or even their domestic appliances. And of course a large swath of the Internet runs on Linux. It is in the best interest of us all that we continually attract and retain brilliant people to contribute to the effort put into developing and maintaining the Linux kernel.

Without wishing to lionise [Linus] above the many others whose work has also contributed to Linux and its success, his contribution to our community has been beyond measure and it has been uncomfortable to see his other side. It’s a step in the right direction to apologize for personal attacks and behavior that drives a wedge into the kernel developer community, and seek to change that behavior. We’d urge others to follow his example, we’re sure every grouping has at times had its personality problems, and it’s never too late to enact some repairs.

While Linus steps away to work on his self improvement, veteran kernel developer Greg Kroah-Hartman will take the reigns among the kernel maintainers.

A Look At The Smallest Magnetic Deflection CRT Ever Made

A high-resolution LCD or OLED screen is a commodity component that we can buy on a little breakout board and plug into our microcontrollers without spending more than a dollar or two. We can buy them in sizes ranging from sub-postage-stamp to desktop TV if our budgets stretch that far, and they are easy to drive in every sense of the word. It is not so long ago though that a high-resolution LCD, even a small one, was a seriously expensive component. In consumer electronic devices such as camcorders engineers went to great lengths to avoid those costs, and [12voltvids] recently took a look at one of them.

Inside the viewfinder of a miniaturized Sony camcorder is a CRT. It’s fairly mundane in the scheme of CRTs, in that it’s a monochrome device with no unexpected features. Except that is, for one thing. It’s tiny, with only a 0.5″ inch screen size. Everything else is the same as your vintage full-sized TV, it has an electron gun and a deflection and focusing coil pack, but the entire device has been miniaturized to the point at which the coil pack is larger than the screen it is driving. On the accompanying PCB are all the support circuits, including a tiny flyback transformer and a single IC –  a Rohm BA7149 electronic viewfinder driver that is as near as possible an entire CRT TV on a chip. That’s it, the whole device runs from a single 5 volt supply.

He doesn’t give the date of the camcorder, but given that it looks as though it uses 8mm cassette tapes and has a curved miniaturized design rather than the angular black exteriors that were fashionable earlier we’d guess it to be from some time around the year 2000. To give it some context, at the time one of the hottest pieces of consumer electronics would have been a Diamond Rio MP3 player, and if your desktop PC had the first of the AMD Athlon processors you probably considered it to be about the fastest you could hope to own. The surprise then is that Sony still considered it more economical even at that point to use the CRT and associated circuitry than a tiny LCD. Either way we’d agree with him that it’s a keeper, a fascinating curio for any electronics enthusiast. If we see an old camcorder going for not a lot, we’ll certainly give it a second look after this.

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Electromagnetic Field: Speczilla!

It is a golden rule of the journalist’s art, that we report the news, we don’t make it. But just occasionally we find ourselves in the odd position of being in the right place such that one of our throwaway comments or actions has the unintended consequence of seeding a story. This is one of those moments, so it’s a rare case of use of the first person in a daily piece as your scribe instead of Hackaday’s usual second person.

At the SHA2017 hacker camp in the Netherlands, [Matt “Gasman” Westcott] gave his presentation on composing a chiptune from an audience suggestion. Afterwards my Tweet about never having seen a Sinclair Spectrum as large as the one on the presentation screen grew a life of its own and became the idea for a project, which in turn at Electromagnetic Field 2018 was exhibited as a giant-sized fully working Sinclair ZX Spectrum.

Since much of the work was performed in Oxford Hackspace I saw Matt’s progression, his first experiments with foam rubber keys, then as he refined his two-wire switch mechanism. Early experiments hooking a row of them up to a real Spectrum motherboard weren’t the success he’d hoped for, so he moved to the FUSE emulator on a Raspberry Pi. A huge effort and needlework learning curve plus a lot of help from OxHack’s textile specialists and buying his local furniture store’s entire stock of foam allowed him to perfect a facsimile of the classic Spectrum’s case and blue rubber keys, while its lettering and iconic BASIC keywords were vinyl-cut at rLab in Reading. A Milton Keynes Makerspace member provided transport to the camp where it was united with a huge TV in a gazebo, completing the trio of local spaces.

At the camp, though it suffered a few technical hitches along the way it was rather a success. There were two techniques, kneeling down and pressing keys with the palm of your hand, or dancing on them in socked feet for complex manoeuvres. The trademark single-key-press BASIC keywords took a little while to re-learn though, there was a time when those were instinctive.

We’d normally wrap a piece like this one up with a link or two. To other projects perhaps, or other hacks from the same person. But in this case we have neither another home computer on this scale, nor any hacks from [Matt], as he’s well known in the European arm of our community for something completely different. As [Gasman] he’s a chiptune artist par excellence, as you can see if you watch his set from the 2014 Electromagnetic Field.

My Career As A Spammer, And Other Stories From The Sneakernet

A large hacker camp is in microcosm a city, it has all the services you might expect to find in a larger settlement in the wider world. There is a telecommunication system, shops, bars, a health centre, waste disposal services, a power grid, and at some camps, a postal system. At Electromagnetic Field, the postal system was provided by the Sneakernet, a select group of volunteers including your Hackaday scribe under the direction of the postmaster Julius ter Pelkwijk. I even had the fun of delivering some chopped pork and ham. (More on that later.) Continue reading “My Career As A Spammer, And Other Stories From The Sneakernet”

Behind The Scenes Of A Hacker Conference

If you’ve been to a few hacker camps then you’re aware they are not the products of giant corporate entities but volunteer run community groups. You may even have volunteered yourself, and done all sorts of interesting tasks that go towards the running of the camp. But few of you will have been on the orga team of a camp, the people who put in the hard work of making it happen from start to finish. Julius ter Pelkwijk has, and at the 2018 Electromagnetic Field camp in the UK he gave us an insight into the experience.

Of course, Julius isn’t a member of the EMF orga, instead the camp that gave him the experience was last year’s SHA2017 in the Netherlands. This was over twice the size of EMF 2018, on the Dutch polder at Scoutinglandgoed Zeewolde, a scout camp in a forest next to a dyke, and while from our perspective it was a huge success, it was fascinating to pull back the curtain and hear from the other side of the event.

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Electromagnetic Field: A Cyberpunk Headdress To Be Noticed In

At the recent Electromagnetic Field hacker camp in the UK, one of the highlights was the Null Sector, a cyberpunk-themed zone best described as something close to the set of Blade Runner made from shipping containers, clever props, and lighting. Our community rose to the occasion with some truly impressive costumes and wearable electronics, lending the venue a real authenticity.

Among the many creations on show there was one that stood quite literally head and shoulders above the rest. [Chebe]’s colour stealing sound reactive LED headdress is a confection of Neopixels, organza, and transparent floor protectors on a wire frame, driven by a Lillypad wearable microcontroller board with a microphone and colour sensor attached. The resulting sound-and-colour-reactive display stood out across a crowded venue full of hackers who’d all made their own efforts to produce similar outfits, which is really saying something!

The Lillypad and LEDs are standard fare, but the wire part of this project isn’t, and that’s what makes it rather interesting from our perspective. Anyone can make something that goes over their head, but to make something that’s comfortable takes a bit of effort and thought. Have you ever tried a set of ill-fitting sunglasses? If you have then you might understand. In this case stiff garden wire is used, bent to shape and joined with rolled-up tape, before being covered with wound-on ribbon for extra comfort. A Hackaday scribe travels the field at a hacker camp, and though [Chebe]’s cranium is a little more petite than the Hackaday bonce it was certainly an enveloping fit when we tried it.

Anyone can attach an LED to an item of clothing and call it a wearable. But to be noticed like this one it has to be done with style. If you’ve not had your fill of this topic, we suggest you continue with the Hackaday Belgrade talk from our friend [Rachel “Konichiwakitty” Wong].