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The Use And Abuse Of CT Scanners

September 20, 2018 by 22 Comments

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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Electromagnetic Field: Speczilla!

September 15, 2018 by 9 Comments

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

September 13, 2018 by 12 Comments

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

September 10, 2018 by 10 Comments

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

September 9, 2018 by 3 Comments

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].

Electromagnetic Field: TIM, A Relay Computer

September 8, 2018 by 12 Comments

We are probably all familiar with computing history to the extent that we know the earliest computers were surprisingly simple devices. While early electronic machines such as Colossus or ENIAC were hugely complex racks of tubes, once expressed as a schematic or as a network of logic gates they would be relatively straightforward for today’s electronic engineer to understand their operation. Those who have made an in-depth study of computing history may have heard of the work of Konrad Zuse in the mid-20th century, his relay-based machines predate their fully electronic cousins by several years.

A relay-based computer can be simple enough to be built by a home constructor, and at the recent Electromagnetic |Field hacker camp [Rory Mangles] outlined his TIM relay computer built while he was at school. It’s an engaging story starting from first principles and describing a series of TIM devices from a simple binary adder to the final fully Turing-complete computer. He describes the design process for his ALU, eventually going with a 1-bit serial design to economise on relays.

The machine has a Harvard architecture, with the program pathway consisting of a paper tape from which the code is run directly. The instruction set is called BLT, which of course means Basic Language of Tim, and there is a T++ assembly language. Loops and if statements are handled in a nod to the classical Turing machine by looping the paper tape. The original TIM is a few years old, but he reveals that he’s recently brought it out of storage and added a parallel port. Thus the finale of the talk is a demonstration, printing a “Hello World”.

We’ve placed the full video below the break, meanwhile we were lucky enough that [Rory] brought TIM along to the EMF Hackaday Readers village for our bring-a-hack, so the header image is from when we had a chance to examine it. If you’re curious to know more, he has a web site with some more TIM details.

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Electromagnetic Field: A Hacked Knitting Machine, Knitting The Universe

September 6, 2018 by 9 Comments

A large hacker camp attracts attendees from all over the world, and at the recent Electromagnetic Field in the UK there were certainly plenty of international visitors. Probably one of those with the longest journey was [Sarah Spencer] from Australia, and she deserves our admiration not just for her work but also for devoting much of her meagre luggage space to the installation she’d brought over for the event. In the lounge tent you could find the Knitted Universe, a map of the night sky with light-up Neopixel constellations covering an entire wall, and among the talks you could find her in-depth description of how  she created it by hacking a 1980s Brother knitting machine into a network printer.

She starts with a potted history of knitting machine hacking, leading to the use of an emulated floppy drive replacing the mechanical item used to store scanned designs on the original hardware. She took an existing hack for a 16-bit Brother knitting machine and re-wrote it for her later 32-bit model, and then created a web interface for it called Octoknit which runs upon a Raspberry Pi. We’re then taken through the operation of a knitting machine and her further adventures in reverse engineering the file format. She ends up with a dithered 4-colour image, but there remains a problem. On the Brother, colour changes are performed by pressing a button, so something to automate the process was required. This task was taken on by her husband, who created an Arduino-driven mechanical button-presser in what had become a team effort. With this in place her only manual task became a periodic adjustment of the weight that preserves the tension in the finished knit.

Finally she moves on to the Knitted Universe itself, which at that point had become something of a viral sensation.  Those of us who have created hacker camp installations will appreciate the volume of work that went into the piece, and she truly deserves the applause at the end of the talk. Watch it below the break, it’s a fascinating half-hour.

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