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

August 30, 2018 by Jenny List 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.

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

August 30, 2018 by Jenny List 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 Jenny List 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.

2018 Electromagnetic Field Badge: It’s An Entire Phone!

August 26, 2018 by Jenny List 16 Comments

As is always the case with a significant hacker camp, we’ve been awaiting the official badge announcement for the upcoming Electromagnetic Field 2018 hacker camp with huge interest. These badges, for readers who may have been on Mars for the past few years, are part of a lively scene of wearable electronics at hacker conferences and camps, and can usually be expected to sport a fully-fledged computer in their own right along with other special functionality.

The announcement of the 2018 badge, dubbed the TiLDA Mk4, does not disappoint. We’d been told that there would be an on-site GSM network for which the welcome packs would contain a SIM, and the well-prepared among us had accordingly dusted off our old Nokia handsets alongside our DECT phones. What we hadn’t expected was that the SIM would be for the badge, because the Mk4 is a fully-fledged hackable mobile phone in its own right. The network will be fully functional for calls and texts within the camp, though since it does not explicitly say so we expect that external calls may be an impossibility. Afterwards though it will remain a usable device on any GSM network, giving it a lease of post-camp life that may see more of them staying in use rather than joining the hacker’s dusty collection in a drawer.

Beyond the party-piece phone it appears to follow the lead of its 2016 predecessor, with the same Python environment atop a TI chipset including an MSP432E4 ARM Cortex M4F microcontroller running at 120MHz with 256kB of internal and 8MB of external RAM, a CC3210 WiFi processor, and the usual battery of sensors, LEDs and GPIOs. Importantly, it also has a Shitty Add-on connector. The 2016 badge was remarkably easy to develop for, and we expect that there will soon be an impressive array of apps for this badge too. If any reader would like to put together a Hackaday feed reader app, we can’t offer you fortune but fame such as we can bestow awaits.

We’ll bring you more information as we have it about the TiLDA Mk4, as well as a hands-on report when one lands in front of us. Meanwhile you’d like to see a retrospective of past EMF badges as a demonstration of where this one has come from, have a read of our coverage of the 2016 and 2014 badges.

3D Printing A Printing Press

August 26, 2018 by Jenny List 3 Comments

If you move among artists, you may have encountered a few printmakers. They create a drawing by cutting through a wax layer that has been deposited on a sheet of copper, then etching the plate and removing the wax. Ink is then rolled onto the plate and cleaned from the flat surface, remaining in the cracks created by the etching. A print is made by putting inked plate and a sheet of paper through a roller press at significant pressure, squeezing the ink from the cracks onto the paper. The result is a beautiful print, but the press required to do the job is by no means cheap.

[Martin Schneider] has addressed this expense with his Open Press project, by producing a printmaking press that can be 3D-printed for a fraction of the outlay of a traditional press. It’s by no means a large model, but appears no less functional for it.

The form of the press is straightforward enough, with a print bed that is drawn between a pair of rollers by a rack-and-pinion gear, and as you would imagine the construction is quite substantial. It’s all CC licensed, and you can make one for yourself if you would like, by downloading the files from Thingiverse.

It’s fair to say that printmaking hasn’t appeared much here, but we can see this press could have significant use beyond artistic applications. Meanwhile it’s a great example of 3D printing providing the means to reduce the barrier to entry for something that was previously quite an expensive pursuit.

Demystifying The ESP8266 With A Series Of Tutorials

August 26, 2018 by Jenny List 28 Comments

If your interest has been piqued by the inexpensive wireless-enabled goodness of the ESP8266 microcontroller, but you have been intimidated by the slightly Wild-West nature of the ecosystem that surrounds it, help is at hand. [Alexander] is creating a series of ESP8266 tutorials designed to demystify the component and lead even the most timid would-be developer to a successful first piece of code.

If you cast your mind back to 2014 when the ESP8266 first emerged, it caused great excitement but had almost no information surrounding it. You could buy it on a selection of modules, but there were no English instructions and no tools to speak of. A community of software and hardware hackers set to work, resulting in a variety of routes into development including the required add-ons to use the ever-popular Arduino framework. Four years later we have a mature and reliable platform, with a selection of higher-quality and well supported boards to choose from alongside that original selection.

The tutorials cover the Arduino and the ESP, as well as Lua and the official SDK. They are written for a complete newcomer, but the style is accessible enough that anyone requiring a quick intro to each platform should be able to gain something.

Our community never ceases to amaze us with the quality of the work that emerges from it. We’ve seen plenty of very high quality projects over the years, and it’s especially pleasing to see someone such as [Alexander] giving something back in this way. We look forward to future installments in this series, and you should keep an eye out for them.

Air Conditioner Remote Reverse Engineered Despite Esoteric Protocol

August 25, 2018 by Jenny List 23 Comments

Infra-red remote control is something of a Done Deal when it comes to hardware hacking, it has been comprehensively reverse engineered, and there exist libraries and software packages to seamlessly take care of all its quirks. Just occasionally though, along comes an IR remote whose protocol doesn’t follow that well-worn path

[William Dudley] found himself in this position with an air-conditioning unit remote control. He found it sent a stream of data with all settings of the machine rather than the single command codes you might expect from a familiar TV remote. The solution was to reverse engineer and reimplement the IR codes.

His reverse engineering relied on an Arduino and IR receiver which he used to sniff the packets coming out of the remote. Eventually he was able to recognise some of the functions from the remote, and create his own protocol that can recreate most of the remote’s functions. This was pushed over to a Raspberry Pi Zero which uses an IR LED to command the air conditioner, joining the ranks of his growing home automation setup.

The write-up makes for a fascinating primer on analysis of obscure IR protocols, and is well worth a read for anybody with an interest in the topic. Meanwhile if you want more IR reverse engineering stories, try this tale of a bathroom scale.