Author: Jenny List

3292 Articles

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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A BCD Clock For Your Desk

September 1, 2018 by 9 Comments

We see so many clocks here at Hackaday, and among those we see our fair share of binary clocks. But to see one that at first sight looks as though it might be a commercial product when it is in fact a one-off project is something special. That’s just what [Tobi4sDE] has done though, with his desktop BCD binary LED clock.

The front panel is a black PCB on which sit the LEDs that form the binary display, and its back holds an ATMega328P microcontroller and DS3231 real-time clock. A smart desktop case is 3D-printed, and while the clock is USB-powered it features a CR2032 coin cell as a backup to hold the time while the USB is disconnected.

Unexpectedly he’s used a mini USB socket rather than the expected micro USB, but the rest of the clock is one we’d probably all have on our desks given the chance. We’d even go so far as to say we’d have this one as a kit if it were available.

Of course, regular readers will notice that this isn’t the only high-standard BCD timepiece you’ll have seen recently, though the other one was a wristwatch.

Dumping A Zelda SNES ROM, And Learning A Few Things Along The Way

August 31, 2018 by 12 Comments

For many of us, being given a big old DIP ROM from nearly thirty years ago and being told to retrieve its contents would be a straightforward enough task. We’d simply do what we would have done in the 1980s, and hook up its address lines to a set of ports, pull its chip select line high, and harvest what came out of the data lines for each address.

But imagine for a minute that an old-fashioned parallel ROM is a component you aren’t familiar with, as [Brad Dettmer] did with the ROM from a SNES Zelda cartridge. We’ve seen plenty of reverse engineering stories with ancient computing gear as their subject, but perhaps it’s time to accept that some of the formerly ubiquitous devices are edging towards that sort of status.

So [Brad] takes us through the process of using the Saleae logic analyser to interrogate the chip while an Arduino stepped through its address lines, and the lesson is probably that while it seems like a sledgehammer to crack a nut it is important to factor in that unfamilarity. If you’d never worked with a 1980s ROM, it would make sense to use the tool you are familiar with, wouldn’t it?

Anyway, all’s well that ends well. While we’re on the subject of Nintendo ROMs, have a read about extracting the boot ROM from a cloned Game Boy.

The Boldport Cordwood And Cuttlefish, Together As A Guitar Tuner

August 30, 2018 by 1 Comment

As regular readers will know, here at Hackaday we are great enthusiasts for the PCB as an art form. On a special level of their own in that arena are the Boldport kits from [Saar Drimer], superlative objets d’art that are beautifully presented and a joy to build.

The trouble some people find with some of their Boldport kits though is that they are just too good. What can you do with them, when getting too busy with hacking them would despoil their beauty? [Paul Gallagher] has the answer in one case, he’s used not one kit but two of them as for a guitar tuner project.

At its heart is a Boldport Cuttlefish ATmega328 development board, and for its display it uses a Cordwood Puzzle as an LED array. All the details are available on a GitHub page, and it’s a modified version of an Arduino guitar tuner he found on Instructables. In particular he’s using a different pre-amp for an electret microphone, and a low-pass filter with a 723Hz cut-off to reduce harmonic content that was confusing the Arduino’s algorithm.

The result is a simple-to-use device with an LED for each string of his guitar, which you can see in the very short YouTube clip below. It joins many other tuners we’ve featured over the years, of which just one is this ATmega168-powered project with MIDI-out.

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GSM Phone Network At EMF Camp Built On Raspberry Pi And LimeSDR

August 30, 2018 by 22 Comments

The Electromagnetic Field 2018 hacker camp in the UK will have its own GSM phone network, and as we have already covered its badge will be a fully-functional GSM phone. This is as far as we are aware a first in the world of badges, and though it may not be a first in hacker camp connectivity it is still no mean achievement at the base station side. To find out more we talked to two of the people behind the network, on the radio side Lime Microsystems‘ [Andrew Back], and on the network side Nexmo‘s developer advocate, [Sam Machin].

There are sixteen base stations spread around the site, of which each one is a Raspberry Pi 3 B+ with a LimeSDR Mini. Development of the system was undertaken prior to the release of the Raspberry Pi Foundation’s PoE board, so they take a separate 24V supply which powers the Pi through a DC-to-DC converter. This arrangement allows for a significant voltage drop should any long cable runs be required.

On the software side the base stations all run the Osmocom (Open Source Mobile Communications) cellular base station infrastructure package. It was a fine decision between the all-in-one Osmocom NITB package and the fully modular Osmocom, going for the former for its reliability. It was commented that this would not necessarily be the case at a future event but that it made sense in the present. It appears on the network as a SIP phone system, meaning that it can easily integrate with the existing DECT network. Let’s take a look at how the network operates from the user side, and the licencing loophole that makes everything possible.

Continue reading “GSM Phone Network At EMF Camp Built On Raspberry Pi And LimeSDR” →

The Electric Vehicles Of Electromagnetic Field: The Ottermobile And The Ottercar

August 30, 2018 by 2 Comments

If you’ve followed these pages over the last few weeks, you’ll have seen an occasional series of posts featuring the comedic electric vehicle creations of the British Hacky Racers series, which will make their debut at the forthcoming Electromagnetic Field hacker camp. So far these intrepid electro-racers have come largely from the UK hackerspace and Robot Wars communities, but it was inevitable that before too long there would arrive some competition from further afield.

[Jana Marie Hemsing] and [Lucy Fauth] are a pair of prolific German hardware hackers whose work you may have seen from time to time in other fields. When they heard about Hacky Racers with barely two weeks until they were due to set off for England for EMF, they knew they had to move fast. The Ottermobile and the Ottercar are the fruits of their labours, and for vehicles knocked together in only two or three days they show an impressive degree of sophistication.

In both cases the power comes courtesy of hoverboard wheels with integrated motors. If you cast your mind back to last year’s SHA Camp in the Netherlands, our coverage had a picture of them on a motorised armchair, so this is a drive system with which they have extensive experience. The Ottercar is based upon a lengthened Kettler kids’ tricycle with the larger variant of the hoverboard motors, and unusually it sports three-wheel drive. Control for the rear pair comes from a hoverboard controller with custom firmware, while the front is supplied by a custom board. The Ottermobile meanwhile is a converted Bobby Car, with hoverboard drive. It’s an existing build that has been brought up to the Hacky Racer rules, and looks as though it could be one of the smaller Hacky Racers.

At the time of writing there is still just about enough time to create a Hacky Racer for Electromagnetic Field. Following the example set from Germany, it’s possible that the hoverboard route could be one of the simplest ways to do it.

Where’s The Cat? Locating Your Moggy Without Eating Batteries

August 28, 2018 by 38 Comments

Where the Hackaday Cat goes when she steps over the threshold into the wider world is a mystery, she reveals her whereabouts strictly on her terms and would we suspect be very cagey were we able to ask her about it. [Andy C] however has a need to know where his cat is spending her time, so he’s made a GPS collar for a bit of feline spying.

There are commercial GPS collars for pets, but they all share the flaw of extremely limited battery life. His challenge then was to create a collar that delivered the required pinpoint fix alongside a battery life measured in months. The solution was a combination of a low-power miniature GPS receiver and a low-power PC microcontroller hooked up to an FSK radio whose frequency he doesn’t give but which we suspect is probably the usual 433 MHz. The collar remains in low power mode until it receives a call on the FSK, at which point it wakes up, gets a GPS fix, transmits it, and returns to sleep.

The summary links to a series of posts which provide an extremely detailed look at all aspects of the project, and go well beyond mere GPS trackers for a cat. If you have an interest in low power devices or antenna matching for example, you’ll find a lot of interesting stuff in these pages. Of course, if all you need is a GPS tracker though, you may prefer a simpler option.