The (UV) Writing’s On The Wall

[Michael Karliner]’s Belshazzar, named for the Biblical character upon whose wall the writing appeared, is a unique light painting machine, that tracks an array of UV LEDs across a glow-in-the-dark background to paint transient dot-matrix letters in light. It was one of many cyberpunk-themed art pieces in Null Sector at the 2018 Electromagnetic Field hacker camp this summer.

The row of LEDs hangs down from a carriage that traverses a tubular rail, and is edged forward by means of a stepper motor driving a roller. This arrangement delivers the benefit that it can be scaled for displays of any length. The LEDs are driven from an Arduino via a Texas Instruments TLC5940 PWM driver ship.The result can be seen in the video below the break, and those who saw it at EMF may remember it tracing suitably dystopian phrases.

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Electromagnetic Field 2018: Event Review

This summer’s Electromagnetic Field hacker camp in a field in western England gave many of the European side of our community their big fix of cool stuff for the year.

Some lucky individuals can spend the year as perpetual travelers, landing in a new country every week or so for the latest in the global round of camps. For the rest of us it is likely that there will be one main event each year that is the highlight, your annual fill of all that our global community has to offer. For many Europeans the main event was the biennial British event, Electromagnetic Field. From a modest start in 2012 this has rapidly become a major spectacle, one of the ones to include in your calendar, delivered both for our community and by our community.

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Faux Aircon Units, Made Entirely From 2D Cuts

2D design and part fabrication doesn’t limit one to a 2D finished product, and that’s well-demonstrated in these Faux Aircon Units [Martin Raynsford] created to help flesh out the cyberpunk-themed Null Sector at the recent 2018 Electromagnetic Field hacker camp in the UK. Null Sector is composed primarily of shipping containers and creative lighting and props, and these fake air conditioner units helped add to the utilitarian ambiance while also having the pleasant side effect of covering up the occasional shipping container logo. Adding to the effect was that the fan blades can spin freely in stray air currents; that plus a convincing rust effect made them a success.

Fan hubs, showing spots for fan blades to be glued. With the exception of embedded bearings, the entire hub (like the rest of the unit) is made from laser-cut MDF.

The units are made almost entirely from laser-cut MDF. The fan blades are cut from the waste pieces left over from the tri-pronged holes, and really showing off the “making 3D assemblies out of 2D materials” aspect are the fan hubs which are (with the exception of bearings) made from laser-cut pieces; a close-up of the hubs is shown here.

Capping off the project is some paint and the rusted appearance. How did [Martin] get such a convincing rust effect? By using real rust, as it turns out. Some cyanoacrylate glue force-cured with misted water for texture, followed by iron powder, then vinegar and hydrogen peroxide with a dash of salt provided the convincing effect. He was kind enough to document the fake rust process on his blog, complete with photos of each stage.

Null Sector showcased a range of creativity; it’s where this unusual headdress was spotted, a device that also showed off the benefits of careful assembly and design.

Retrotechtacular: Here’s How They Programmed the EDSAC Computer

When you write a program for your computer, whether it is a desktop machine, a microcontroller, or a supercomputer, the chances are that you use software tools to help you get the job done. High level languages, compilers, linkers, assemblers, debuggers, and code libraries have become so integrated that in many cases you will barely be aware of their existence. To all intents and purposes this huge toolchain will be the computer. But the first computer programmers had none of these luxuries. They had to hand assemble their own binaries, check them by hand, and debug them by guessing what had happened when they failed.

EDSAC I, 1948, W.Renwick with 5 hole tape reader and Creed teleprinter. Copyright Computer Laboratory, University of Cambridge. Reproduced by permission. [CC BY 2.0 UK]
EDSAC I, 1948, W.Renwick with 5 hole tape reader and Creed teleprinter. Copyright Computer Laboratory, University of Cambridge. Reproduced by permission. [CC BY 2.0 UK]
EDSAC (Electronic delay storage automatic calculator) was the first computer operated by the University of Cambridge in the UK and one of the first few computers in the entire world when it was built in the late 1940s. It is the subject of the 1951 film you’ll find embedded below. Originally produced for a conference, the video sports a 1976 introduction and narration from the machine’s creator Professor Maurice Wilkes. It doesn’t take us through the design of the machine itself, instead it concentrates on the workflow required to program it.

The Paper-Heavy Process of Programming EDSAC

To illustrate the programming process, a committee of people who would now call themselves computer scientists, but probably then called themselves mathematicians, breaking a formula into subroutines before the code is laboriously hand assembled. The linking process is performed manually too by the secretary who types the code into a teletype for transfer to a punched tape. When a library function is required she reaches into a filing cabinet for the roll of tape containing it before running it through a tape duplicator to add it to the program. Finally the completed tape is checked and added to a job queue that consists of a row of hooks on the wall. Never complain that your toolchain is unwieldy again!

The original EDSAC was decommissioned in the late 1950s after serving the university and spawning a commercial version, the LEO, which became the first ever computer manufactured for use in commerce. That was not the end of the EDSAC story though, because in this century a team at the National Museum of Computing at Bletchley Park set about recreating EDSAC as an exhibit. And as luck would have it a member of that team was at the recent Electromagnetic Field hacker camp to give a talk about their work which you will also find below.

Building a Faithful Reproduction of EDSAC

Tony Abbey gives us both a history of the machine and a description of its architecture, followed by a run through their efforts in rebuilding it. You may be surprised by some of the unexpected facts from the talk. For instance, while all the tubes used in the EDSAC are still available, their bases are not. Equivalents were sourced from China, but team members had to modify them with dental drills.

They also needed to manufact the 1940s-style tube chassis, and the solution to that problem happened to be just down the road. Bletchley is part of modern-day Milton Keynes, a post-war new town that is also home to another famous name: Marshall amplifiers. Tube amps are built in a surprisingly similar way, so they took on the manufactured challenge. Not all the parts of the new EDSAC are original though. The memory used mercury delay lines in 1949, but for 2018 recreation the computer has a delay line using nickel wire and modern components. Tony admits that even that has caused problems, and there is a simulator using a microcontroller.

You can see the restored EDSAC at the National Museum of Computing. We visited it in 2016, and you can read our review. Meanwhile if you are an FPGA wizard, you can even have a virtual EDSAC of your own.

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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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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.

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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