Ourselves As Others See Us Through The Lens Of Traditional Media

August 29, 2017 by Jenny List 25 Comments

When I presented myself at the SHACamp 2017 info desk bright and early on the first full day of the camp, I was surprised to find that I was to be assigned a volunteer along with my press badge. Because of the way our community is sometimes covered by the traditional media, it was necessary that any journalists touring the site have a helping hand to ensure that they respect the privacy of the attendees, gain permission from people likely to be in any photographs, and generally not be idiots about the whole Hacker thing. I pointed out that I was working for Hackaday and not The Sun, and that as an active hackspace member and former hackspace director I was very much a part of the community attending SHA 2017 who would simply be wasting the valuable time of any volunteer assigned to me. Fortunately for the next volunteer in line they agreed with my point of view, so one of the angels was spared a day of my breakneck walking pace and impenetrable British colloquialisms.

It’s interesting therefore a few weeks after the event, to investigate how it was portrayed through the eyes of people who aren’t coming as Hackaday is, from within the bubble. To take a look at that disconnect between what we know about our community and its events, and how the traditional media sometimes like to portray us. Are they imagining the set of a Hollywood “hacker” movie in which assorted geniuses penetrate the computer systems of various international institutions by the simple expedient of banging wildly at a keyboard for a few seconds, or will the reality of a bunch of like-minded technology enthusiasts gathering in a field for several days of tinkering and other fun activities be what makes their reports?

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A Flame Diode Pilot Light Sensor For A Burning Man Installation

August 28, 2017 by Jenny List 22 Comments

A naked flame is a complex soup of ionised gases, that possesses an unexpected property. As you might expect with that much ionisation there is some level of electrical conductivity, but the unusual property comes in that a flame can be made to conduct in only one direction. In other words, it can become a diode of sorts, in a manner reminiscent of a vacuum tube diode.

[Paul Stoffregen] has made use of this phenomenon in a flame detector that he’s built to be installed on a Burning Man flame-based art installation. It forms part of a response to a problem with traditional pilot lights: when the wind blows a pilot light out, a cloud of unignited gas can accumulate. The sensor allows the pilot light to be automatically re-ignited if the flame is no longer present.

The circuit is a surprisingly simple one, with a PNP transistor being turned on by the flame diode being placed in its base circuit. This allows the intensity of the flame to be measured as well as whether or not it is present, and all at the expense of a microscopic current consumption. A capacitor is charged by the transistor, and the charge time is measured by a Teensy that uses it to estimate flame intensity and trigger the pilot light if necessary. Interestingly it comes from a patent that expired in 2013, it’s always worth including that particular line of research in your investigations.

All the construction details are in the page linked above, and you can see the system under test in the video below the break.

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Britain Invented Rock-N-Roll, And Other Stories

August 28, 2017 by Jenny List 58 Comments

An elderly relative of mine used to get irate at the BBC news. When our Prime Minister [Edward Heath] or another of her bêtes noirs of the day came on, she’d rail at the radio or the TV, expressing her views to them in no uncertain terms. It taught a young me a lot about the futility of shouting at the telly, as well as about making a spectacle of oneself.

The ISS in flight. NASA(Public Domain) — The ISS in flight. NASA [Public domain].

The other evening though I found myself almost at the point of shouting at a TV programme, and since it’s one with a clear message about technology I feel it’s worth sharing here. The programme in question was one of the Impossible Engineering series, and it was talking about the technology behind the International Space Station. It was recent enough to include last year’s mission involving [Tim Peake], so it was by no means a show dredged from the archives.

All very well, you say. Impossible Engineering‘s format of looking at a modern engineering marvel and tracing the historical roots of some of its innovations would find fertile ground in the ISS, after all it’s one of our most impressive achievements and could easily provide content for several seasons of the show. And I’ll give them this, they did provide an interesting episode.

The trouble was, they made an omission. And it wasn’t just a slight omission, one of those minor cock-ups that when we Hackaday scribes make them the commenters pounce upon with glee, this one was a doozy. They managed to fill an hour of television talking about space stations and in particular a space station that was assembled by multiple countries under an international co-operation, without mention of any of the Russian technology that underpins much of its design. An egregious example among many was their featuring a new Boeing capsule designed to touchdown on land rather than on water as a novel invention, when as far as I am aware every Russian capsule ever made has performed a land-based touchdown.

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Turning On Your Amplifier With A Raspberry Pi

August 27, 2017 by Jenny List 17 Comments

Life is good if you are a couch potato music enthusiast. Bluetooth audio allows the playing of all your music from your smartphone, and apps to control your hi-fi give you complete control over your listening experience.

Not quite so for [Daniel Landau] though. His Cambridge Audio amplifier isn’t quite the latest generation, and he didn’t possess a handy way to turn it on and off without resorting to its infrared remote control. It has a proprietary interface of some kind, but nothing wireless to which he could talk from his mobile device.

His solution is fairly straightforward, which in itself says something about the technology available to us in the hardware world these days. He took a Raspberry Pi with the Home Assistant home automation package and the LIRC infrared subsystem installed, and had it drive an infrared LED within range of the amplifier’s receiver. Coupled with the Home Assistant app, he was then able to turn the amplifier on and off as desired. It’s a fairly simple use of the software in question, but this is the type of project upon which so much more can later be built.

Not so many years ago this comparatively easy project would have required a significant amount more hardware and effort. A few weeks ago [John Baichtal] took a look at the evolution of home automation technology, through the lens of the language surrounding the term itself.

Via Hacker News.

A Functioning 3D Printer For 10€

August 26, 2017 by Jenny List 42 Comments

There was a time when crowdfunding websites were full of 3D printers at impossibly low prices. You knew that it would turn out to be either blatant vaporware or its delivery date would slip into the 2020s, but still there seemed always to be an eager queue ready to sign up. Even though there were promised models for under $200, $150, and then $100, there had to be a lower limit to the prices they were prepared to claim for their products. A $10 printer on Kickstarter for example would have been just a step too far.

There is a project that’s come close to that mark though, even though the magic figure is 10 euros rather than 10 dollars, so just short of 12 dollars at today’s exchange rate. [Michele Lizzit] has built a functioning 3D printer for himself, and claims that magic 10€ build price. How on earth has he done it? The answer lies in extensive use of scrap components, in this case from broken inkjet printers and an image scanner. These provide all the mechanical parts for the printer, leaving him only having to spend his 10€ on some hot end parts and the printer’s electronics. In an unusual move, the frame of the machine appears to come from a set of cardboard biscuit boxes, a master stroke of junk box construction.

The claimed resolution is 33µm, and using the position encoders from the inkjet printers he is able to make it a closed loop device. We salute his ingenuity in building such an impressive printer from so little, and were we ever locked by the bad guys in a room full of IT junk and lacked a handy escape device, we’d wish to be incarcerated with [Michele] any day over [Angus MacGyver] or [Sgt. Bosco BA Baracus].

You can see the printer in action in the video below the break.

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Blast Your Battery’s Sulphates, Is It Worth It?

August 25, 2017 by Jenny List 55 Comments

When a friend finds her caravan’s deep-cycle battery manager has expired over the summer, and her holiday home on wheels is without its lighting and water pump, what can you do? Faced with a dead battery with a low terminal voltage in your workshop, check its electrolyte level, hook it up to a constant current supply set at a few hundred mA, and leave it for a few days to slowly bring it up before giving it a proper charge. It probably won’t help her much beyond the outing immediately in hand, but it’s better than nothing.

A lot of us will own a lead-acid battery in our cars without ever giving it much thought. The alternator keeps it topped up, and every few years it needs replacing. Just another consumable, like tyres or brake pads. But there’s a bit more to these cells than that, and a bit of care and reading around the subject can both extend their lives in use and help bring back some of them after they have to all intents and purposes expired.

One problem in particular is sulphation of the lead plates, the build-up of insoluble lead sulphate on them which increases the internal resistance and efficiency of the cell to the point at which it becomes unusable. The sulphate can be removed with a high voltage, but at the expense of a dangerous time with a boiling battery spewing sulphuric acid and lead salts. The solution therefore proposed is to pulse it with higher voltage spikes over and above charging at its healthy voltage, thus providing the extra kick required to shift the sulphation build up without boiling the electrolyte.

If you read around the web, there are numerous miracle cures for lead-acid batteries to be found. Some suggest adding epsom salts, others alum, and there are even people who talk about reversing the charge polarity for a while (but not in a Star Trek sense, sadly). You can even buy commercial products, little tablets that you drop in the top of each cell. The problem is, they all have the air of those YouTube videos promising miracle free energy from magnets about them, long on promise and short on credible demonstrations. Our skeptic radar pings when people bring resonances into discussions like these.

So so these pulse desulphators work? Have you built one, and did it bring back your battery from the dead? Or are they snake oil? We’ve featured one before here, but sadly the web link it points to is now only available via the Wayback Machine.

A Disc Shooter For When Rubber Bands Or Nerf Darts Aren’t Enough

August 25, 2017 by Jenny List 27 Comments

There are times in everybody’s life when they feel the need to shoot at things in a harmless manner. For those moments there are rubber bands and Nerf darts, but even then they feel like mere toys. If that is the point at which you find yourself, then maybe [Austin]’s home-made electric disc shooter can help.

Operation of the shooter is simple enough. A stack of 3D-printed plastic discs is loaded into a tubular magazine, from which individual disks are nudged by a motor-driven cam controlled by the trigger. Once the disc leaves the magazine it reaches a vacuum cleaner belt driven by a much more powerful motor, that accelerates the disc to ejection velocity.

The video below the break shows the gun’s construction, as well as a sequence involving the destruction of plenty of balloons, soda cans, and food items. The 3D-printed ammunition seems to us to be the weak link as in our experience it is inevitable that there is a high ammunition loss rate with these type of weapons, but maybe [Austin] has a line on some cheap filament. Either way, his disc gun looks like the kind of toy that could provide an entertaining diversion for many readers.

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