EMF Fire Pong

August 11, 2016 by Jenny List 8 Comments

One of the installations that consistently drew a large crowd after dark at EMF Camp 2016 was a game. This wasn’t a conventional computer game though, instead it was a line of gas jets along which a pair of players had to bat a jet of flame between them at ever-increasing speed until one player missed the return. This was the Fire Pong game created by members of Nottingham Hackspace, and though there seems to have been no online write-up of it as yet they have posted enough pictures of its build for us to deduce something of its construction.

A network of gas pipes and jets with all valves brought out to a clearly labeled control panel appears to control the gas flow through solenoid valves connected to a relay board driven by what appears to be an Arduino Pro Mini. The bats are huge for theatrical effect, but contain accelerometers to sense player swipes and send the information back to the gas control circuits. A pair of much larger flame generators indicate the end of a rally, and the score is displayed on a large LED scoreboard. There is very likely to be more to the system than we can glean from these pictures and a shot of the various components, but as yet we are so-to-speak in the dark on their details.

If you will excuse the quality constraints of a mobile phone camera in a darkened field, a video of the game in action is below the break. There was a significant queue for a turn at the bat, this was one of the event’s more popular night-time attractions.

Continue reading “EMF Fire Pong” →

TiLDA MKπ, The EMF Camp 2016 Badge

August 9, 2016 by Jenny List 15 Comments

The Scottish Consulate has stamped its last passport, the Dutch fire tower has belched its final flame, and the Gold Members Lounge has followed the Hacienda and the Marquee into clubland oblivion. EMF Camp 2016 is over, so all the 1500 or so attendees have left are the memories, photographs, and festival diarrhoea to remind them of their three days in the Surrey countryside.

Well, not quite all, there is the small matter of the badge.

In the case of EMF 2016 it was called TiLDA MKπ, and since there was a point earlier in the year when it seemed the badge might never see the light of day it represents a significant achievement from the EMF badge team.

The badge features an STM32L486VGT6 ARM Cortex M4 running at 80MHz, a 320×240 pixel colour LCD, magnetometer and accelerometer, and a CC3100 WiFi processor. The firmware provides a simple interface to an app store containing an expanding array of micropython apps from both the EMF Camp team and submitted by event attendees. As shipped the badge connects to one of the site networks, but this can be adjusted to your own network after the event. It’s been designed for ease of hacking, requiring only a USB connection and mounting as a disk drive without need for special software or IDE. A comprehensive array of I/O lines are brought out to both 0.1″ pitch pins and 4mm edge-mounted holes. At the EMF Camp closing speeches there was an announcement of a competition with a range of prizes for the best hardware and software uses for the badge.

shane-tweetThe TiLDA causes a sticky moment for our colleague, Tindie scribe Shane. — The TiLDA causes a sticky moment for our colleague, Tindie scribe Shane.

As is so often the case the badge was not without its teething troubles, as the network coped with so many devices connecting at once and the on-board Neopixel turned out to have been mounted upside down. Our badge seemed to have a bit of trouble maintaining a steady network connection and apps frequently crashed with miscellaneous Python errors, though a succession of firmware updates have resulted in a more stable experience. But these moments are part of the badge experience; this is after all an event whose attendees are likely to have the means to cope with such problems.

All the relevant files and software for the badge are fully open-source, and can be found in the EMF Camp GitHub repositories. We’ve put a set of images of the board in a gallery below if you are curious. The pinout images are courtesy of the EMF badge wiki.

We’ve featured EMF badges before, here’s our look at the EMF 2014 device.

Fail Of The Week: The Pitfalls Of Designing A Wideband Radio

August 5, 2016 by Jenny List 11 Comments

If you are someone whose interests lie in the field of RF, you won’t need telling about the endless field of new possibilities opened up by the advent of affordable software defined radio technology. If you are a designer or constructor it might be tempting to believe that these radios could reduce some of the problems facing an RF design engineer. After all, that tricky signal processing work has been moved into code, so the RF engineer’s only remaining job should be to fill the not-so-huge gap between antenna and ADC or DAC.

In some cases this is true. If you are designing an SDR front end for a relatively narrow band of frequencies, perhaps a single frequency allocation such as an amateur band, the challenges are largely the same as those you’d find in the front end of a traditional radio. The simplest SDRs are thus well within the abilities of a home constructor, for example converting a below-100kHz-wide segment of radio spectrum to the below-100kHz baseband audio bandwidth of a decent quality computer sound card which serves as both ADC and DAC. You will only need to design one set of not-very-wide filters, and the integrated circuits you’ll use will not be particularly exotic.

But what happens if the SDR you are designing is not a simple narrow-band device? [Chris Testa, KD2BMH] delivered a talk at this year’s Dayton Hamvention looking at some of the mistakes he made and pitfalls he encountered over the last few years of work on his 50MHz to 1GHz-bandwidth Whitebox handheld SDR project. It’s not a FoTW in the traditional sense in that it is not a single ignominious fail, instead it is a candid and fascinating examination of so many of the wrong turnings a would-be RF engineer can make.

The video of his talk can be found below the break, courtesy of Ham Radio Now. [Chris]’s talk is part of a longer presentation after [Bruce Perens, K6BP] who some of you may recognise from his activities when he’s not talking about digital voice and SDRs. We’re jumping in at about the 34 minute mark to catch [Chris], but [Bruce]’s talk is almost worth an article in itself..

Continue reading “Fail Of The Week: The Pitfalls Of Designing A Wideband Radio” →

From Project To Kit: Getting The Hardware Right

August 5, 2016 by Jenny List 29 Comments

In the previous article in this series on making a personal electronic project into a saleable kit, we looked at the broader picture of the kit market for a new entrant, the importance of gauging whether or not your proposed kit has a viable niche and ensuring that it has a good combination of buildability, instructions, and quality. In this article we will look at specifying and pricing the hardware side of a kit, illustrating in detail with an example project. The project we’ve chosen is a simple NE555 LED flasher which we haven’t built and have no intention of assembling into a kit for real, however it provides a handy reference project without the circuit itself having any special considerations which might distract from the job at hand.

Continue reading “From Project To Kit: Getting The Hardware Right” →

EMF: You Shall Find Us At The Sign Of The Jolly Wrencher

August 4, 2016 by Jenny List 2 Comments

It’s frustrating, the reluctance of some of my fellow hackspace members to put the cordless drill battery back in the charger after use. As this is being written I’ve just coaxed enough energy from the drill to make a few holes in a piece of PVC pipe that will form part of an improvised flagpole, and upon that pole will hang Hackaday’s Jolly Wrencher flag at this weekend’s EMF Camp. We’re sharing a village with Oxford Hackspace, and as both your Hackaday scribe and an OxHack member the last week has been a little busy.

In theory it’s a simple enough process, getting a hackspace and all its assorted accoutrements down to Guildford. Three or four members’ cars will be loaded to the gunwales and will set off in good time to have everything under way without still desperately getting ready when the fun begins. In practice it’s been a procession of narrowly averted disasters, from the gazebo someone bought at auction turning out to have five walls and no roof, to the large ball that forms an essential part of one of the projects OxHack will be featuring being a buy-while-stocks-last remaindered product from last years Argos catalogue that only certain stores seem to still have.

We’ll be on the border between camping areas A and B, next to our friends from the Netherlands. I’m told that this location was requested due to likely proximity to a source of stroopwafels. If you come along on Friday between 6 and 8 PM we’re holding the Tindie bring-a-hack event, at which we’ll be inviting attendees to bring along their hacks to share with the masses. All projects are welcome, but if you have a Hackaday Prize entry, a Hackaday.io project or a Tindie item we’d especially love to see you. My colleague Jasmine assures me that there will be a limited amount of Hackaday and Tindie swag on offer.

If you’re going down to EMF Camp this weekend then please drop by and have a chat if you’re passing our village. Otherwise you’ll probably encounter us on our travels as we try to seek out the interesting projects and hacks to feature on these pages. We hope the British weather doesn’t deliver any unpleasant surprises, and may all your projects work when you demonstrate them in front of the masses!

Jenny List is a director of Oxford Hackspace when she is not writing for Hackaday.

Electrostatic Loudspeakers: High End HiFi You Can Build Yourself

August 3, 2016 by Jenny List 52 Comments

If you have an interest in audio there are plenty of opportunities for home construction of hi-fi equipment. You can make yourself an amplifier which will be as good as any available commercially, and plenty of the sources you might plug into it can also come into being on your bench.

There will always be some pieces of hi-fi equipment which while not impossible to make will be very difficult for you to replicate yourself. Either their complexity will render construction too difficult as might be the case with for example a CD player, or as with a moving-coil loudspeaker the quality you could reasonably achieve would struggle match that of the commercial equivalent. It never ceases to astound us what our community of hackers and makers can achieve, but the resources, economies of scale, and engineering expertise available to a large hi-fi manufacturer load the dice in their favour in those cases.

The subject of this article is a piece of extreme high-end esoteric hi-fi that you can replicate yourself, indeed you start on a level playing field with the manufacturers because the engineering challenges involved are the same for them as they are for you. Electrostatic loudspeakers work by the attraction and repulsion of a thin conductive film in an electric field rather than the magnetic attraction and repulsion you’ll find in a moving-coil loudspeaker, and the resulting very low mass driver should be free of undesirable resonances and capable of a significantly lower distortion and flatter frequency response than its magnetic sibling.
Continue reading “Electrostatic Loudspeakers: High End HiFi You Can Build Yourself” →

HardwareX Is A Scientific Journal For Open Hardware

August 2, 2016 by Jenny List 19 Comments

Disruption is a basic tenet of the Open Hardware movement. How can my innovative use of technology disrupt your dinosaur of an establishment to make something better? Whether it’s an open-source project chipping away at a monopoly or a commercial start-up upsetting an industry with a precarious business model based on past realities, we’ve become used to upstarts taking the limelight.

As an observer it’s interesting to see how the establishment they are challenging reacts to the upstart. Sometimes the fragility of the challenged model is such that they collapse, other times they turn to the courts and go after the competitor or even worse, the customers, in an effort to stave off the inevitable. Just occasionally though they embrace the challengers and try to capture some of what makes them special, and it is one of these cases that is today’s subject.

A famously closed monopoly is the world of academic journals. A long-established industry with a very lucrative business model hatched in the days when its product was exclusively paper-based, this industry has come under some pressure in recent years from the unfettered publishing potential of the Internet, demands for open access to public-funded research, and the increasing influence of the open-source world in science.

Elsevier, one of the larger academic publishers, has responded to this last facet with HardwareX, a publication which describes itself as “an open access journal established to promote free and open source designing, building and customizing of scientific infrastructure“. In short: a lot of hardware built for scientific research is now being created under open-source models, and this is their response.

Some readers might respond to this with suspicion, after all the open-source world has seen enough attempts by big business to embrace its work and extend it into the proprietary, but the reality is that this is an interesting opportunity for all sides. The open access and requirement for all submissions to be covered under an open hardware licence mean that it would be impossible for this journal to retreat behind any paywalls. In addition the fact of it being published in a reputable academic journal will bring open-source scientific hardware to a new prominence as it is cited in papers appearing in other journals. Finally the existence of such a journal will encourage the adoption of open-source hardware in the world of science, as projects are released under open-source licences to fulfill the requirements for submission.

So have the publishing dinosaurs got it right, and is this journal an exciting new opportunity for all concerned? We think it has that potential, and the results won’t be confined to laboratories. Inevitably the world of hackers and makers will benefit from open-source work coming from scientists, and vice versa.

Thanks [Matheus Carvalho] for the tip.

Bookbinding workshop image: By Nasjonalbiblioteket from Norway [No restrictions], via Wikimedia Commons.