There Is No Such Thing As An Invalid Unit

September 19, 2017 by Jenny List 356 Comments

The Mars Climate Orbiter was a spacecraft launched in the closing years of the 1990s, whose job was to have been to study the Martian atmosphere and serve as a communications relay point for a series of other surface missions. It is famous not for its mission achieving these goals, but for the manner of its premature destruction as its orbital insertion brought it too close to the planet’s atmosphere and destroyed it.

The ill-fated Mars Climate Orbiter craft. NASA [Public domain].

The cause of the spacecraft entering the atmosphere rather than orbiting the planet was found in a subsequent investigation to be a very simple one. Simplifying matters to an extent, a private contractor supplied a subsystem which delivered a reading whose units were in the imperial system, to another subsystem expecting units in the SI, or metric system. The resulting huge discrepancy caused the craft to steer towards the surface of the planet rather than the intended orbit, and caused the mission to come to a premature end. Billions of dollars lost, substantially red faces among the engineers responsible.

This unit cock-up gave metric-using engineers the world over a brief chance to feel smug, as well as if they were being honest a chance to reflect on their good fortune at it not having happened on their watch. We will all at some time or another have made an error with respect to our unit calculations, even though in most cases it’s more likely to have involved a simple loss of a factor of ten, and not with respect to a billion dollar piece of space hardware.

But it also touches on one of those fundamental divides in the world between the metric and imperial systems. It’s a divide that brings together threads of age politics, geography, nationalism, and personal choice, and though it may be somewhere angels fear to tread (we’ve seen it get quite heated before to the tune of 885+ comments), it provides a fascinating subject for anyone with an interest in engineering culture.

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In-Band Signaling: Quindar Tones

September 19, 2017 by Dan Maloney 29 Comments

So far in this brief series on in-band signaling, we looked at two of the common methods of providing control signals along with the main content of a transmission: DTMF for Touch-Tone dialing, and coded-squelch systems for two-way radio. For this installment, we’ll look at something that far fewer people have ever used, but almost everyone has heard: Quindar tones.

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AI: This Decade’s Worst Buzz Word

September 18, 2017 by Al Williams 84 Comments

In hacker circles, the “Internet of Things” is often the object of derision. Do we really need the IoT toaster? But there’s one phrase that — while not new — is really starting to annoy me in its current incarnation: AI or Artificial Intelligence.

The problem isn’t the phrase itself. It used to mean a collection of techniques used to make a computer look like it was smart enough to, say, play a game or hold a simulated conversation. Of course, in the movies it means HAL9000. Lately, though, companies have been overselling the concept and otherwise normal people are taking the bait.

The Alexa Effect

Not to pick on Amazon, but all of the home assistants like Alexa and Google Now tout themselves as AI. By the most classic definition, that’s true. AI techniques include matching natural language to predefined templates. That’s really all these devices are doing today. Granted the neural nets that allow for great speech recognition and reproduction are impressive. But they aren’t true intelligence nor are they even necessarily direct analogs of a human brain.

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Sneakers: A Love-Fest

September 15, 2017 by John Baichtal 62 Comments

“A TURNIP CURES ELVIS” begins the opening credits, an intriguing beginning to a smart and still timely film that was released around 25 years ago. If you’ve never seen the movie, I’m about to spoil the hell out of it.

Sneakers features the title characters, hackers who work the 1992 gig economy as freelance penetration testers. They work for Martin Bishop, a hippie hacker Obi Wan who works San Francisco’s gray market, doing good deeds and helping banks improve their security.

While there is a fair amount of cheese in Sneakers, a lot of the problems the characters face — physical security and cryptography come to mind — remain the problems of today. Securing our digital business? Check. Surveillance? Check? Gray operators? Absolutely. At the same time, the movie does a good job of exploring different categories of hacker. The various characters seem to offer glimpses of people I see all the time at the hackerspace. Bigger than life, certainly, but they are in a Hollywood movie, after all.

Finally, the movie is just smart. Those opening credits offer a preview: the anagrams that begin the movie (“A TURNIP KILLS ELVIS” translates to Universal Pictures) are not just some art director’s conceit for the opening credits. The anagrams end up being important later on in the film, where there is a key clue hidden but if you think about it, shuffling letters on your Scrabble tray could be taken as a metaphor for hacker thinking — taking the same information as everyone else but looking at it in a different way.

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A Noob’s Guide To McMaster-Carr

September 13, 2017 by Sonya Vasquez 177 Comments

For the penny-pinching basement hacker, McMaster-Carr seems like a weird go-to resource for hardware. For one, they’re primarily a B2B company; and, for two, their prices aren’t cheap. Yet their name is ubiquitous among the hacker community. Why? Despite the price, something makes them too useful to ignore by everyday DIY enthusiasts. Those of us who’ve already been enlightened by the McMaster-Carr can design wonders with a vocabulary of parts just one day away at the click of a button.

Today, this article is for those of us who have yet to receive that enlightenment. When used wisely, this source of mechanical everything brings us a world of fast parts at our fingertips. When used poorly, we find nothing but overpriced stock components in oversized shipping boxes.

Since we, the McMaster-Carr sages, are forever doomed to stuff our desk drawers with those characteristic yellow baggies till the end of time, we thought we’d give an intro to the noobs that are just beginning to flex their muscles with this almighty resource. Grab another cup of coffee as we take you on a tour of the good and good-grievances of McMaster-Carr.

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Video Streaming Like Your Raspberry Pi Depended On It

September 12, 2017 by Lewin Day 23 Comments

The Raspberry Pi is an incredibly versatile computing platform, particularly when it comes to embedded applications. They’re used in all kinds of security and monitoring projects to take still shots over time, or record video footage for later review. It’s remarkably easy to do, and there’s a wide variety of tools available to get the job done.

However, if you need live video with as little latency as possible, things get more difficult. I was building a remotely controlled vehicle that uses the cellular data network for communication. Minimizing latency was key to making the vehicle easy to drive. Thus I set sail for the nearest search engine and begun researching my problem.

My first approach to the challenge was the venerable VLC Media Player. Initial experiments were sadly fraught with issues. Getting the software to recognize the webcam plugged into my Pi Zero took forever, and when I did get eventually get the stream up and running, it was far too laggy to be useful. Streaming over WiFi and waving my hands in front of the camera showed I had a delay of at least two or three seconds. While I could have possibly optimized it further, I decided to move on and try to find something a little more lightweight.

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Hack Space Debris At Your Peril

September 11, 2017 by Steven Dufresne 41 Comments

Who has dibs on space debris? If getting to it were a solved problem, it sure would be fun to use dead orbital hardware as something of a hacker’s junk bin. Turns out there is some precedent for this, and regulations already in place in the international community.

To get you into the right frame of mind: it’s once again 2100 AD and hackers are living in mile-long space habitats in the Earth-Moon system. But from where do those hackers get their raw material, their hardware? The system abounds with space debris, defunct satellites from a century of technological progress. According to Earth maritime law, if space is to be treated like international waters then the right of salvage would permit them to take parts from any derelict. But is space like international waters? Or would hacking space debris result in doing hard time in the ice mines of Ceres?

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