Beer And Hacks In London And Beyond

August 18, 2016 by Jenny List 4 Comments

We’ve been all over the UK this month, our most recent Hackaday gathering just two nights past. With much hardware and hacker show and tell (recounted below) I wanted to make sure nobody missed the chance to join in as we’ll be in Bletchley on Saturday and in Cambridge on Wednesday. Whether you need more convincing to walk out the door and join in the fun, or just want to the see the excellent hardware so far displayed, keep reading to share in the fun from Wednesday night.

London pubs have an unfavourable image among provincial folk, one of being strange neon-lit places populated by vast crowds of very loud people in suits drinking cheap wine at expensive prices. The truth is though that the capital’s pubs are as diverse as those anywhere else in the country, from shabby quiet backstreet boozers with their aged customers nursing pints of Fullers to achingly hipster faux-Victorian gin-palaces in which young men sporting preposterous beards they’ll regret in five years time drink microbrewery ales you won’t have heard of served in glass tankards. On a hot August evening the patrons spill out onto the pavement and provide a handy reference to the would-be drinker as to the nature of the establishment.

This warm-evening exodus served our community well night before last, for when a group of Hackaday readers and Tindie sellers converged upon a pub in Fitzrovia there was enough room to reach the bar and though it was hardly quiet we could at least discuss the things we’d brought along. My colleague [Jasmine] had organised the event and was on hand with a pile of stickers and other swag.

A select group of hackers and makers made the journey. Some of them, such as my friend [David], I had encountered frequently online but never met in person so it was good to put a face to a name, while others I knew only by the reputation they had garnered through the projects they’d put on Hackaday.io or Tindie. I will undoubtedly fail to mention a few names in this quick round-up of a few of the projects, so before I start I would like to thank everyone for coming along and making it such a good evening.

[Jasmine] as seen by [Mike]'s LED screen. — [Jasmine] as seen by [Mike]’s LED screen.

Electric Stuff from Mike’s Workshop

Most visible because of an extensive range of very bright LED projects was [Mike], of [Mike’s Electric Stuff] fame. His PCB density was impressive, though he did admit to having a pick-and-place machine. Especially useful for those large LED matrices. Of note was a pentagonal LED screen with integrated camera, originally part of an LED screen polyhedron. This board offered a rare glimpse of a Raspberry Pi Compute Module in the wild.

Scope Probe Sans Pound Sink

Opposite me for most of the evening was [Leonerd], with his oscilloscope current probe adapter. This board as you might expect contains a very low value shunt resistor and an amplifier, allowing the accurate measurement of low current transients without laying down the GDP of a small country to buy one from a high-end test equipment manufacturer. I was party to a very interesting conversation between him and [Mike] on the subject of instrumentation amplifiers, something of personal interest from my experience with RF test equipment.

A Wild Z80 Appeared

Also present was [Spencer] with his RC2014 Z80-based computer. He’d brought along the fully tricked-out version with keyboard and screen, and had it running a fractal graphic generator written in BASIC. It’s a project that touches a spot in the heart of people of a certain age, if your first computer came from Sir Clive Sinclair then maybe you’ll understand.

The value of the evening was not solely in the kits and projects on display though. Whenever you get a group from our wider community together in a convivial environment the creative discourse flows in unexpected direction, knowledge is shared, and new ideas are formed. Part of the global Hackaday and Tindie community got to know each other yesterday evening, and from that will come fresh projects. They may not necessarily change the world, but everything has to start somewhere.

This event was one of a short series following our successful bring-a-hack at EMF Camp. We were very pleased to see the projects people brought along, they comprehensively eclipsed the little radio board that was my offering. The run of UK events isn’t over, we have ones coming up at Bletchley and Cambridge, and as always keep an eye on the Hackaday.io events page for global events within our community.

Capacitive Imaging With A Raspberry Pi Touch Screen

August 18, 2016 by Jenny List 15 Comments

We use touch screens all the time these days, and though we all know they support multiple touch events it is easy for us to take them for granted and forget that they are a rather accomplished sensor array in their own right.

[Optismon] has long held an interest in capacitive touch screen sensors, and has recently turned his attention to the official Raspberry Pi 7-inch touchscreen display. He set out to read its raw capacitance values, and ended up with a fully functional 2D capacitive imaging device able to sense hidden nails and woodwork in his drywall.

Reading the capacitance values is not a job for the faint-hearted though. There is an I2C bus which is handled by the Pi GPU rather than the processor, and to read it in software would require a change to the Pi’s infamous Broadcom binary blob. His solution which he agrees is non-optimal was to take another of the Pi’s I2C lines that he could talk to and connect it in parallel with the display line. As a result he can catch the readings from the screen’s sensors and with a bit of scripting make a 2D display on the screen. The outlines of hands and objects on his desk can clearly be seen when he places them on the screen, and when he runs the device over his wall it shows the position of the studding and nails behind the drywall.

He’s posted his code in a GitHub repository, and put up the YouTube video of his capacitive imaging in action which you can watch below the break.

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Universal Serial Abuse

August 17, 2016 by Jenny List 26 Comments

It’s probable that most Hackaday readers are aware of their own computer security even if they are not specialists. You’ll have some idea of which ports your machines expose to the world, what services they run, and you’ll know of a heap of possible attack vectors even if you may not know about every last one.

So as part of that awareness, it’s likely you’ll be wary of strange USB devices. If someone drops a Flash drive in the parking lot the chances of one of you blithely plugging it into your laptop is not high at all. USB ports are trusted by your computer and its operating system, and to have access to one is to be given the keys to the kingdom.

Our subject today is a DEF CON talk courtesy of [Dominic White] and [Rogan Dawes] entitled “Universal Serial aBUSe“, and it details a USB attack in which they create an innocuous USB stick that emulates a keyboard and mouse which is shared across a WiFi network via a VNC server. This gives an attacker (who can gain momentary physical access to a USB port to install the device) a way into the machine that completely bypasses all network and other security measures.

Their hardware features an AVR and an ESP8266, the former for USB and HID work and the latter to do the heavy lifting and provide WiFi. They started with a Cactus Micro Rev2, but graduated to their own compatible board to make the device more suitable to pose as a USB stick. Both hardware and software files can be found on their GitHub repository, with the software being a fork of esp-link. They go into significant detail of their development and debugging process, and their write-up should be an interesting read for anyone.

Below the break you can find a video description of the attack. It’s not a shock to know that USB ports have such little defense, but it is a sobering moment to realize how far attacks like this one have come into the realm of what is possible.

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Bone Conduction Skull Radio

August 17, 2016 by Jenny List 20 Comments

There are many ways to take an electrical audio signal and turn it into something you can hear. Moving coil speakers, plasma domes, electrostatic speakers, piezo horns, the list goes on. Last week at the Electromagnetic Field festival in the UK, we encountered another we hadn’t experienced directly before. Bite on a brass rod (sheathed in a drinking straw for hygiene), hear music.

This was Skull Radio, a bone conduction speaker courtesy of [Tdr], one of our friends from TOG hackerspace in Dublin, and its simplicity hid a rather surprising performance. A small DC motor has its shaft connected to a piece of rod, and a small audio power amplifier drives the motor. Nothing is audible until you bite on the rod, and then you can hear the music. The bones of your skull are conducting it directly to your inner ear, without an airborne sound wave in sight.

The resulting experience is a sonic cathedral from lips of etherial sibilance, a wider soft palate soundstage broadened by a tongue of bass and masticated by a driving treble overlaid with a toothy resonance before spitting out a dynamic oral texture. You’ll go back to your hi-fi after listening to [Tdr]’s Skull Radio, but you’ll know you’ll never equal its unique sound.

(If you are not the kind of audiophile who spends $1000 on a USB cable, the last paragraph means you bite on it, you hear music, and it sounds not quite as bad as you might expect.)

This isn’t the first bone conduction project we’ve featured here, we’ve seen a Bluetooth speaker and at least one set of headphones, but our favorite is probably this covert radio.

Hackerspacing: Making A Temperature Logger

August 13, 2016 by Jenny List 7 Comments

The folks at Swindon Makerspace took possession of a new space a few months ago after a long time in temporary accommodation. They’ve made impressive progress making it their own, and are the envy of their neighbours.

A small part of the new space is a temperature logger, and it’s one whose construction they’ve detailed on their website. It’s a simple piece of hardware based around a Dallas DS18B20 1-wire temperature sensor and an ESP8266 module, powered by 3 AA batteries and passing its data to data.sparkfun.com. The PCB was created using the space’s CNC router, and the surface-mount components were hand-soldered. The whole thing is dwarfed by its battery box, and will eventually be housed in its own 3D printed case. Sadly they’ve not posted the files, though it’s a simple enough circuit that’s widely used, it looks similar to this one with the addition of a voltage regulator.

The device itself isn’t really the point here though, instead it serves here to highlight the role of a typical small hackspace in bringing simple custom electronic and other prototyping services to the grass roots of our community. Large city hackspaces with hundreds of members will have had the resources to create the space program of a small country for years, but makers in provincial towns like Swindon – even with their strong engineering heritage – have faced an uphill struggle to accumulate the members and resources to get under way.

So to the wider world it’s a simple temperature logger but it really represents more than that — another town now has a thriving and sustainable makerspace. Could your town do the same?

If you’ve never used a Dallas 1-wire temperature sensor like the one the Swindon folks have in their logger, we suggest you read our primer on the parts and their protocol.

A VNA On A 200 Euro Budget

August 13, 2016 by Jenny List 24 Comments

If you were to ask someone who works with RF a lot and isn’t lucky enough to do it for a commercial entity with deep pockets what their test instrument of desire would be, the chances are their response would mention a vector network analyser. A VNA is an instrument that measures the S-parameters of an RF circuit, that rather useful set of things to know whose maths in those lectures as an electronic engineering student are something of a painful memory for some of us.

The reason your RF engineer respondent won’t have a VNA on their bench already will be fairly straightforward. VNAs are eye-wateringly expensive. Second-hand ones are in the multi-thousands, new ones can require the keys to Fort Knox. All this is no obstacle to [Henrik Forstén] though, he’s built himself a 30MHz to 6 GHz VNA on the cheap, with the astoundingly low budget of 200 Euros.

On paper, the operation of a VNA is surprisingly simple. RF at a known power level is passed through the device under test into a load, and the forward and reverse RF is sampled on both its input and output with a set of directional couplers. Each of the four couplers feeds what amounts to an SDR, and the resulting samples are processed by a computer. His write-up contains a full run-down of each section of the circuit, and is an interesting primer on the operation of a VNA,

[Henrik] admits that his VNA isn’t as accurate an instrument as its commercial cousins, but for his tiny budget the quality of his work is evident in that it is a functional VNA. He could have a batch of these assembled and he’d find a willing queue of buyers even after taking into account the work he’s put in with his pricing.

[Henrik]’s work has appeared on these pages several times before, and every time he has delivered something special. We’ve seen his radar systems, home-made horn antennas, and a very well-executed ARM single board computer. This guy is one to watch.

Thanks [theEngineer] for the tip.

From Project To Kit: Instructions Are Everything

August 12, 2016 by Jenny List 26 Comments

A printed copy of the instructions for our example kit

We’ve had two previous articles in this series on turning a personal electronic project into a saleable kit, in which we’ve examined the kit market in a broader context for a new entrant, and gone on to take a look at the process of assembling the hardware required to create a product. We’ve used an NE555 LED flasher as a simple example , from which we’ve gone through the exercise of setting a cost of production and therefore a retail price.

The remaining task required to complete our kit production is to write the documentation that will accompany it. These will be the instructions from which your customers will build the kit, and their success and any other customers they may send your way will hang on their quality. So many otherwise flawless kits get this part of the offering so wrong, so for a kit manufacturer it represents an easy win into which to put some effort.
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