Star Trackers: Telling Up From Down In Any Space

April 2, 2020 by Maya Posch 28 Comments

Keeping track of position is crucial in a lot of situations. On Earth, it’s usually relatively straight-forward, with systems having been developed over the centuries that would allow one to get at least a rough fix on one’s position on this planet. But for a satellite out in space, however, it’s harder. How do they keep their communications dishes pointed towards Earth?

The stars are an obvious orientation point. The Attitude and Articulation Control Subsystem (AACS) on the Voyager 1 and 2 space probes has the non-enviable task of keeping the spacecraft’s communication dish aligned precisely with a communications dish back on Earth, which from deep space is an incomprehensibly tiny target.

Back on Earth, the star tracker concept has become quite popular among photographers who try to image the night skies. Even in your living room, VR systems also rely on knowing the position of the user’s body and any peripherals in space. In this article we’ll take a look at the history and current applications of this type of position tracking. Continue reading “Star Trackers: Telling Up From Down In Any Space” →

Gold Cables Really Do Work The Best

April 1, 2020 by Jenny List 88 Comments

As a writer, I have long harboured a dream that one day an editor will buy me a top-of-the-range audio analyser, and I can set up an audio test lab and write pieces debunking the spurious claims made by audiophiles, HiFi journalists, and the high-end audio industry about the quality of their products. Does that amp really lend an incisive sibilance to the broader soundstage, and can we back that up with some measurable figures rather than purple prose?

An Audio Playground You Didn’t Know You Had

An Audio Precision APx525 audio analyser. Bradp723 (CC-BY-SA 3.0)

Sadly Hackaday is not an audio magazine, and if Mike bought me an Audio Precision he’d have to satisfy all the other writers’ test equipment desires too, and who knows where that would end! So there will be no Hackaday audio lab — for now. But that doesn’t mean I can’t play around with audio analysis.

Last month we carried a write-up of a Supercon talk from Kate Temkin and Michael Ossmann, in which they reminded us that we have a cracking general purpose DSP playground right under our noses; GNU Radio isn’t just for radio. Once I’d seen the talk my audio analysis horizons were opened up considerably. Maybe that audio analyser wouldn’t be mine, but I could do some of the same job with GNU Radio.

It’s important to stress at this point that anything I can do on my bench will not remotely approach the quality of a professional audio analyser. But even if I can’t measure infinitesimal differences between very high-end audio circuitry, I can still measure enough to tell a good audio product from a bad one.

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Perhaps August Dvorak Is More Your Type

March 31, 2020 by Kristina Panos 129 Comments

One of the strangest things about human nature is our tendency toward inertia. We take so much uncontrollable change in stride, but when our man-made constructs stop making sense, we’re suddenly stuck in our ways — for instance, the way we measure things in the US, or define daytime throughout the year. Inertia seems to be the only explanation for continuing to do things the old way, even when new and scientifically superior ways come along. But this isn’t about the metric system — it’s about something much more personal. If you use a keyboard with any degree of regularity, this affects you physically.

Many, many people are content to live their entire lives typing on QWERTY keyboards. They never give a thought to the unfortunate layout choices of common letters, nor do they pick up even a whisper of the heated debates about the effectiveness of QWERTY vs. other layouts. We would bet that most of our readers have at least heard of the Dvorak layout, and assume that a decent percentage of you have converted to it.

Hardly anyone in the history of typewriting has cared so much about subverting QWERTY as August Dvorak. Once he began to study the the QWERTY layout and all its associated problems, he devoted the rest of his life to the plight of the typist. Although the Dvorak keyboard layout never gained widespread adoption, plenty of people swear by it, and it continues to inspire more finger-friendly layouts to this day.

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Behind The Scenes Of Folding@Home: How Do You Fight A Virus With Distributed Computing?

March 31, 2020 by Roger Cheng 25 Comments

A great big Thank You to everyone who answered the call to participate in Folding@Home, helping to understand proteins interactions of SARS-CoV-2 virus that causes COVID-19. Some members of the FAH research team hosted an AMA (Ask Me Anything) session on Reddit to provide us with behind-the-scenes details. Unsurprisingly, the top two topics are “Why isn’t my computer doing anything?” and “What does this actually accomplish?”

The first is easier to answer. Thanks to people spreading the word — like the amazing growth of Team Hackaday — there has been a huge infusion of new participants. We could see this happening on the leader boards, but in this AMA we have numbers direct from the source. Before this month there were roughly thirty thousand regular contributors. Since then, several hundred thousands more started pitching in. This has overwhelmed their server infrastructure and resulted in what’s been termed a friendly-fire DDoS attack.

The most succinct information was posted by a folding support forum moderator.

Here’s a summary of current Folding@Home situation :
* We know about the work unit shortage
* It’s happening because of an approximately 20x increase in demand
* We are working on it and hope to have a solution very soon.
* Keep your machines running, they will eventually fold on their own.
* Every time we double our server resources, the number of Donors trying to help goes up by a factor of 4, outstripping whatever we do.

Why don’t they just buy more servers?

The answer can be found on Folding@Home donation FAQ. Most of their research grants have restrictions on how that funding is spent. These restrictions typically exclude capital equipment and infrastructure spending, meaning researchers can’t “just” buy more servers. Fortunately they are optimistic this recent fame has also attracted attention from enough donors with the right resources to help. As of this writing, their backend infrastructure has grown though not yet caught up to the flood. They’re still working on it, hang tight!

Computing hardware aside, there are human limitations on both input and output sides of this distributed supercomputer. Folding@Home need field experts to put together work units to be sent out to our computers, and such expertise is also required to review and interpret our submitted results. The good news is that our contribution has sped up their iteration cycle tremendously. Results that used to take weeks or months now return in days, informing where the next set of work units should investigate.

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Coronavirus Testing Follow-Up: Rapid Immunologic Testing

March 30, 2020 by Dan Maloney 12 Comments

When I started writing my recent article on COVID-19 testing, I assumed that I would be doing a compare and contrast sort of article. Like many people, I assumed that the “gold standard” test would be the reverse transcriptase-polymerase chain reaction (RT-PCR) test that I described in some detail. And indeed it is, but it’s not without its problems, such as the lack of certified labs and the need for trained technicians to run the samples. I also assumed there would be another test, a simple serological test that could use antibodies to discern if there was an active or even a previous, resolved infection.

At the time I wrote the first article, I could find no indication of an immunologic test for COVID-19 (more specifically, a test for SARS-Cov-2, the virus that causes COVID-19). But almost as rapidly as the number of COVID-19 cases rises, the news changes, and it appears that simple, rapidly performed antibody tests are now or soon will be available. They likely won’t replace the gold standard RT-PCR test, but they do stand to be a game-changer for the front line providers and the victims of this disease. So it pays to take a quick look at immunoassays for infectious diseases, and learn how they work.

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Phantom Express: The Spaceplane That Never Was

March 27, 2020 by Tom Nardi 12 Comments

Even for those of us who follow space news closely, there’s a lot to keep track of these days. Private companies are competing to develop new human-rated spacecraft and assembling satellite mega-constellations, while NASA is working towards a return the Moon and the first flight of the SLS. Between new announcements, updates to existing missions, and literal rocket launches, things are happening on a nearly daily basis. It’s fair to say we haven’t seen this level of activity since the Space Race of the 1960s.

With so much going on, it’s no surprise that not many people have heard of the XS-1 Phantom Express. A project by the United States Defense Advanced Research Projects Agency (DARPA), the XS-1 was designed to be a reusable launch system that could put small payloads into orbit on short notice. Once its mission was complete, the vehicle was to return to the launch site and be ready for re-flight in as a little as 24 hours.

Alternately referred to as the “DARPA Experimental Spaceplane”, the vehicle was envisioned as being roughly the size of a business jet and capable of carrying a payload of up to 2,300 kilograms (5,000 pounds). It would take off vertically under rocket power and then glide back to Earth at the end of the mission to make a conventional runway landing. At $5 million per flight, its operating costs would be comparable with even the most aggressively priced commercial launch providers; but with the added bonus of not having to involve a third party in military and reconnaissance missions which would almost certainly be classified in nature.

Or at least, that was the idea. Flight tests were originally scheduled to begin this year, but earlier this year prime contractor Boeing abruptly dropped out of the program. Despite six years in development and over $140 million in funding awarded by DARPA, it’s now all but certain that the XS-1 Phantom Express will never get off the ground. Which is a shame, as even in a market full of innovative launch vehicles, this unique spacecraft offered some compelling advantages.

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Stay Informed: How To Pull Your Own COVID-19 Data

March 26, 2020 by Tom Nardi 34 Comments

For all the technology we have, it can still be frustratingly difficult to get any concrete information from the media. Sometimes all you want to do is to cut through the noise and see some real numbers. Watching talking heads argue for a half hour probably isn’t going to tell you much about how the COVID-19 virus is spreading through your local community, but seeing real-time data pulled from multiple vetted sources might.

Having access to the raw data about COVID-19 cases, fatalities, and recoveries is, to put it mildly, eye-opening. Even if day to day life seems pretty much unchanged in your corner of the world, seeing the rate at which these numbers are climbing really puts the fight into perspective. You might be less inclined to go out for a leisurely stroll if you knew how many new cases had popped up in your neck of the woods during the last 24 hours.

But this article isn’t about telling you how to feel about the data, it’s about how you can get your hands on it. What you do with it after that is entirely up to you. Depending on where you live, the numbers you see might even make you feel a bit better. It’s information on your own terms, and in these uncertain times, that might be the best we can hope for.

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