Spanning The Tree : Dr Radia Perlman & Untangling Networks

May 29, 2018 by Richard Baguley 33 Comments

As computer networks get bigger, it becomes increasingly hard to keep track of the flow of data over this network. How do you route data, making sure that the data is spread to all parts of the network? You use an algorithm called the spanning tree protocol — just one of the contributions to computer science of a remarkable engineer, Dr. Radia Perlman. But before she created this fundamental Internet protocol, she also worked on LOGO, the first programming language for children, creating a dialect for toddlers.

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Hacking When It Counts: The Pioneer Missions

May 25, 2018 by Dan Maloney 16 Comments

If the heady early days of space exploration taught us anything, it was how much we just didn’t know. Failure after failure mounted, often dramatic and expensive and sometimes deadly. Launch vehicles exploded, satellites failed to deploy, or some widget decided to give up the ghost at a crucial time, blinding a multi-million dollar probe and ending a mission long before any useful science was done. For the United States, with a deadline to meet for manned missions to the moon, every failure in the late 1950s and early 1960s was valuable, though, at least to the extent that it taught them what not to do next time.

For the scientists planning unmanned missions, there was another, later deadline looming that presented a rare opportunity to expand our knowledge of the outer solar system, a strange and as yet unexplored wilderness with the potential to destroy anything humans could build and send there. Before investing billions in missions to take a Grand Tour of the outer planets, they needed more information. They needed to send out some Pioneers.

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Ask Hackaday: How Do You DIY A Top-Octave Generator?

May 24, 2018 by Elliot Williams 157 Comments

One of the great joys of Hackaday are the truly oddball requests that we sometimes get over the tip line. Case in point: [DC Darsen] wrote in with a busted 1970s organ in need of a new top-octave generator, and wondered if we could help. He had found a complicated but promising circuit online, and was wondering if there was anything simpler. I replied “I should be able to get that done with a single Arduino” and proceeded to prove myself entirely wrong in short order.

So we’re passing the buck on to you, dear Hackaday reader. Can you help [DC Darsen] repair his organ with a minimum amount of expenditure and hassle? All we need to do is produce twelve, or maybe thirteen, differently pitched square waves simultaneously.

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Mechanisms: Solenoids

May 23, 2018 by Dan Maloney 34 Comments

Since humans first starting playing with electricity, we’ve proven ourselves pretty clever at finding ways to harness that power and turn it into motion. Electric motors of every type move the world, but they are far from the only way to put electricity into motion. When you want continuous rotation, a motor is the way to go. But for simpler on and off applications, where fine control of position is not critical, a solenoid is more like what you need. These electromagnetic devices are found everywhere and they’re next in our series on useful mechanisms.

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Robert Hall And The Solid-State Laser

May 22, 2018 by Dan Maloney 14 Comments

The debt we all owe must be paid someday, and for inventor Robert N. Hall, that debt came due in 2016 at the ripe age of 96. Robert Hall’s passing went all but unnoticed by everyone but his family and a few close colleagues at General Electric’s Schenectady, New York research lab, where Hall spent his remarkable career.

That someone who lives for 96% of a century would outlive most of the people he had ever known is not surprising, but what’s more surprising is that more notice of his life and legacy wasn’t taken. Without his efforts, so many of the tools of modern life that we take for granted would not have come to pass, or would have been delayed. His main contribution started with a simple but seemingly outrageous idea — making a solid-state laser. But he ended up making so many more contributions that it’s worth a look at what he accomplished over his long career.

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Explaining Efail And Why It Isn’t The End Of Email Privacy

May 21, 2018 by Pedro Umbelino 25 Comments

Last week the PGPocalipse was all over the news… Except that, well, it wasn’t an apocalypse.

A team of researchers published a paper(PDF) where they describe how to decrypt a PGP encrypted email via a targeted attack. The research itself is pretty well documented and, from a security researcher perspective, it’s a good paper to read, especially the cryptography parts.

But we here at Hackaday were skeptical about media claims that Efail had broken PGP. Some media reports went as far as recommending everyone turn off PGP encryption on all email clients., but they weren’t able to back this recommendation up with firm reasoning. In fact, Efail isn’t an immediate threat for the vast majority of people simply because an attacker must already have access to an encrypted email to use the exploit. Advising everyone to disable encryption all together just makes no sense.

Aside from the massive false alarm, Efail is a very interesting exploit to wrap your head around. Join me after the break as I walk through how it works, and what you can do to avoid it.

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3D Printering: When An STL File Is Not Quite Right

May 16, 2018 by Donald Papp 50 Comments

STL files are everywhere. When there’s something to 3D print, it’s probably going to be an STL. Which, as long as the model is good just as it is, is no trouble at all. But sooner or later there will be a model that isn’t quite right in some way and suddenly project progress hits a snag.

When models interface with other physical things, those other components may not always be exactly as the designer expected. Being mindful about such potential inconsistencies during the design phase can help prevent problems, but it’s not always avoidable. The reason it’s a problem is because an STL file represents a solid model as a finished unit; it is not really intended to be rolled back into CAD programs for additional design changes.

STL files can be edited, but just like re-modeling a component from scratch, it can be a tricky process for those who don’t live and breathe this stuff. I’ll describe a few common issues related to STLs that can hold up getting that new project together, along with ways to deal with them. Thanks to 3D printing becoming much more commonplace, basic tools are within reach of even the least CAD-aware among us.

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