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.
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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.

Your Laundry Is Done!

August 1, 2016 by Jenny List 20 Comments

Have you ever put a load of dirty clothing in the washing machine and set the cycle running, only to forget all about it and discover a mouldering congealed mass in the machine a few days later? [Xose Pérez] has more than once, and to stop it happening again he’s got a project that monitors the machine in his basement and notifies him when his wash is done.

At the centre of his washing machine monitor is an ITead Sonoff IoT mains on-off switch. This device contains a 10A mains relay, an ESP8266 chip to control it, and a small mains switch-mode power supply. The Sonoff doesn’t use the ESP’s ADC pins, so he’s broken one of them out on a lead to a current transformer which captures the power level being consumed by the washing machine. The Sonoff is one of those IoT devices that relies on a proprietary cloud service and doesn’t have its own API, so [Xose] has created his own firmware for it incorporating an ESP port of an Arduino current sensing library. To round off the project and because he could, he’s added an ambient humidity sensor to the device.

The resulting boxed-up unit returns minute-by-minute current readings for the entire wash cycle. To spot when the cycle has finished, he waits for a moment when it has been using no power for more than five minutes, at which point his Node-RED system sends him a notification via Pushover.

This project is a very neatly executed hack on an extremely cheap piece of hardware whose capabilities would ordinarily be somewhat curtailed due to its proprietary interface. Surprisingly it’s not the first laundry monitor we’ve seen here at Hackaday, we’ve had this apartment laundry monitor using an accelerometer and a Raspberry Pi, and a notifier for a finicky dryer that insisted on stopping mid-cycle.

The Tiny Radio Telescope

July 31, 2016 by Jenny List 40 Comments

Radio telescopes are one of the more high-profile pieces of scientific apparatus. There is an excitement to stories of radio astronomers of old probing the mysteries of the Universe on winter nights in frigid cabins atop massive parabolas, even if nowadays their somewhat more fortunate successors do the same work from the comfort of their labs using telescopes that may be on the other side of the world.

You might think if you look at the Arecibo Observatory, Lovell Telescope, or other famous pieces of apparatus, that this is Big Science, out of reach for mere mortals such as yourself without billion-dollar research programs. Maybe [Paul Scott] and [Allen Versfeld]’s Tiny Radio Telescope project will change that view.

The NRAO published a radio telescope design a few years ago for use mainly as an educational tool, the Itty Bitty Telescope. It used a satellite TV dish and LNB feeding a signal meter as a simple telescope to detect the Sun, and black body radiation from the surrounding objects. It’s a simple design for kids to get their heads around, and [Scott] and [Allen] have set out to turn it into something more useful with an RTL-SDR instead of a signal meter and a motorised mount for automated observations.

This is one of those projects on Hackaday.io that moves slowly but you know will eventually deliver on its promise. With a 1m dish and a consumer LNB it’s never going to make a discovery that will rock the world, but that’s not the point. It may be science that the astrophysicists moved on from decades ago, but it’s still quite an achievement that the radio sky can be imaged using such mundane equipment.

We’ve featured backyard radio astronomy before a few times, from this UHF school science project to another satellite TV based telescope. Keep them coming!

A thank you to Southgate ARC for the prod.

A One LED Clock

July 29, 2016 by Jenny List 18 Comments

Esoteric clocks are something of a staple among hardware hacker projects. If it can be made to tell the time correctly, even if only twice a day, the chances are someone’s made a clock from it. And if the only person who can read that clock is its creator, so much the better. Universal accessibility is not always a virtue in the world of unusual timepieces.

[Setvir] writes to us with details of his One LED Clock. It’s an Arduino Pro Micro with an RTC module and an LED. That’s all, time is communicated to the world through LED flashes. You might expect therefore that it would use Morse Code, but he’s come up with his own timing communication scheme which does have some merit. Long flashes cover a quarter of the clock face, while short flashes cover individual hours or five-minute segments. He goes into detail on the project page and we can see that once you are used to the scheme it has an elegance to it, but it certainly ticks the essential unreadable-to-the-uninitiated box for an esoteric clock.

We like it though for its simplicity and for the flashing scheme, which once explained is both efficient and easy to read. If you would like to have a go yourself he’s published his code, so go forth and cover the world with baffling single-LED timepieces!

We’ve featured a few minimalist LED clocks before, at least one with a minimal face, and another single-LED offering. But that one used a bi-colour LED, so [Setvir] takes the minimalism crown.

[Nick Thatcher]’s Plan-B Is A Commuter Electric Unicycle

July 29, 2016 by Jenny List 19 Comments

[Nick Thatcher] is a serial builder of self-balancing rides. His various Segway clones and unicycles have until now suffered from one significant problem, that of portability when not being ridden. Taking one on a train was a significant undertaking, hardly convenient in a personal transport machine.

His latest design, the Plan-B, is an electric unicycle designed to address this problem to create a truly portable piece of commuter transport. It has been designed to be as compact as possible with the ability to fold to fit in a confined space, and the weight has been reduced to a minimum.

Power comes from a 24V 350W geared motor kept on a leash through a Dimension Engineering motor controller by an Arduino with a gyro to maintain the unit’s stability The battery is an ULTRAMAX LiFePO4 , and the single wheel is an inexpensive plastic wheelbarrow part with chain drive from the motor.

The result is both rideable and portable, though with a 10mph top speed not the fastest of personal transport. He’s posted a video which you can see below the break, showing him taking it on a train journey and traversing the British urban landscape.

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From Project To Kit: So You Want To Sell Electronic Kits

July 29, 2016 by Jenny List 41 Comments

Many of us have enjoyed building electronic projects that come not from our own inspiration or ingenuity but from a ready-made kit. It makes sense, after all in buying a kit you should receive a tried-and-tested design that you can assemble without some of the heartache associated with getting a self-designed project right. And though in recent years the barriers to entry into the professional PCB market for small projects have lowered significantly, there is still an attraction to a kit that comes with a decent PCB and case.

The kit version of the Sinclair ZX81 microcomputer. By Smaddison (Own work) [CC BY-SA 3.0], via Wikimedia Commons.

If you start your electronic odyssey through kit-building, you gain more than a set of electronic projects. You learn about the circuits you build, and you gain a feel for how a well-designed project should go together. Eventually this feeds into your own projects, and in time you are producing builds that equal or surpass those you can buy as kits.

From the point of having a nicely executed project to that of wondering whether it too could be sold as a kit is not a huge step. This is the first of a series of articles that will examine the kit manufacturing process from project to customer, and will with luck deliver some insight to those of you who have always wondered whether you could make it as a kit vendor.

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