Ben Franklin’s Weak Motor And Other Forgotten Locomotion

October 3, 2017 by Steven Dufresne 11 Comments

Most of the electric motors we see these days are of the electromagnetic variety, and for good reason: they’re powerful. But there’s a type of motor that was invented before the electromagnetic one, and of which there are many variations. Those are motors that run on high voltage, and the attraction and repulsion of charge, commonly known as electrostatic motors.

Ben Franklin — whose electric experiments are most frequently associated with flying a kite in a thunderstorm — built and tested one such high-voltage motor. It wasn’t very powerful, but was good enough for him to envision using it as a rotisserie hack. Food is a powerful motivator.

What follows is a walk through the development of various types of these motors, from the earliest ion propelled ones to the induction motors which most have never heard of before, even an HV hacker such as yours truly.

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Books You Should Read: Feynman’s Appendix To The Challenger Disaster Report

October 2, 2017 by Donald Papp 84 Comments

It isn’t really a book, but Richard Feynman’s Appendix to the Challenger Disaster Report is still definitely something you should read. It’s not particularly long, but it’s educational and relevant not just as an example of critical thinking in action, but as a reminder not to fool oneself; neither individually, nor on an organizational level. Sadly, while much was learned from the events leading to and surrounding the Challenger disaster, over thirty years later many of us can still find a lot of the same things to relate to in our own professional lives. There isn’t a single magic solution, because these problems are subtle and often masquerade as normal.

Feynman and the Challenger Disaster

Richard Feynman (1918-1988) was a Nobel Prize winning physicist and one of the best-known scientists of his time. In 1986 he somewhat reluctantly agreed to join the Rogers Commission, whose task was to investigate the Challenger disaster. The space shuttle Challenger had exploded a little more than a minute after launch, killing everyone on board. The commission’s job was to find out what had gone wrong and how it had happened, and figure out how to keep it from happening again.

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We’re Using The Word Firmware Wrong

September 29, 2017 by Mike Szczys 123 Comments

I had an interesting discussion the other day about code written for an embedded system. I was speaking with Voja Antonic about ‘firmware’. The conversation continued forward but I noticed that he was calling it ‘software’. We later discussed it and Voja told me he thought only the parts of the code directly interacting with the microcontroller were firmware; the rest falls under the more generic term of software. It really had me wondering where firmware stops being firmware and is merely software?

The topic has remained on my mind and I finally got around to doing some dictionary searches. I’m surprised that I’ve been using the word differently and I think most of the people I’ve heard use it are doing the same — at least as far as dictionary definitions are concerned. My go to sources are generally Merriam-Webster and Oxford English dictionaries and both indicate that firmware is a type of software that is indelible:

Permanent software programmed into a read-only memory.

–Oxford English Dictonary

computer programs contained permanently in a hardware device (such as a read-only memory)

–Merriam-Webster Dictonary

According to this definition, I have never written a single bit of firmware. Everything I have written has been embedded software. But surely this is a term that must change with the times as technology progress so I kept digging.

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The Engineering That Survives Hurricanes

September 27, 2017 by Bryan Cockfield 84 Comments

Florida is a great place to live, especially around January when it’s sunny and 24 degrees outside (76F) while all of your friends from back home are dealing with scraping ice off of their windshields every morning. In the late summer, though, this pleasant tropical paradise can sometimes take a turn for the worse, because Florida is one of the handful of places that frequently see some of the worst storms on the planet: hurricanes. As a Floridian myself, perhaps I can shed some light on some of the ways that the various local governments and their residents have taken to mitigate the destruction that usually accompanies these intense tropical storms when it seems that, to outsiders, it might be considered unwise to live in such a place.

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Return To The Asus Tinker Board: Have Six Months Changed Anything?

September 26, 2017 by Jenny List 70 Comments

Back in February this year, we ordered a new single board computer, and reviewed it. The board in question was the Asus Tinker Board, a Raspberry Pi 3 competitor from the electronics giant in a very well-executed clone of the Raspberry Pi form factor.

Our review found its hardware to be one of the best of that crop of boards we had yet seen, but found serious fault with the poor state of its software support at the time. There was no website, the distro had to be downloaded from an obscure Asus download site, and there was no user community or support channel to speak of. We were then contacted by some of the folks from Asus who explained that the board had not yet been officially launched, and that the unit we’d secured had escaped the fold a little early. Continue reading “Return To The Asus Tinker Board: Have Six Months Changed Anything?” →

An Introduction To Solid State Relays

September 26, 2017 by Sean Boyce 56 Comments

When we think of relays, we tend to think of those big mechanical things that make a satisfying ‘click’ when activated. As nice as they are for relay-based computers, there are times when you don’t want to deal with noise or the unreliability of moving parts. This is where solid-state relays (SSRs) are worth considering. They switch faster, silently, without bouncing or arcing, last longer, and don’t contain a big inductor.

An SSR consists of two or three standard components packed into a module (you can even build one yourself). The first component is an optocoupler which isolates your control circuit from the mains power that you are controlling. Second, a triac, silicon controlled rectifier, or MOSFET that switches the mains power using the output from the optocoupler. Finally, there is usually (but not always) a ‘zero-crossing detection circuit’. This causes the relay to wait until the current it is controlling reaches zero before shutting off. Most SSRs will similarly wait until the mains voltage crosses zero volts before switching on.

If a mechanical relay turns on or off near the peak voltage when supplying AC, there is a sudden drop or rise in current. If you have an inductive load such as an electric motor, this can cause a large transient voltage spike when you turn off the relay, as the magnetic field surrounding the inductive load collapses. Switching a relay during a peak in the mains voltage also causes an electric arc between the relay terminals, wearing them down and contributing to the mechanical failure of the relay.

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Cuban Embassy Attacks And The Microwave Auditory Effect

September 25, 2017 by Adam Fabio 323 Comments

If you’ve been paying attention to the news, you may have seen a series of articles coming out about US staffers in Cuba. It seems that 21 staffers have suffered a bizarre array of injuries ranging from hearing loss to dizziness to concussion-like traumatic brain injuries. Some staffers have reported hearing incapacitating sounds in the embassy and in their hotel rooms. The reports range from clicking to grinding, humming, or even blaring sounds. One staffer described being awoken to a horrifically loud sound, only to have it disappear as soon as he moved away from his bed. When he got back into bed, the mysterious sound came back.

Cuba has denied any wrongdoing. However, the US has already started to take action – expelling two Cuban diplomats from the US in May. The question though is what exactly could have caused these injuries. The press has gone wild with theories of sonic weaponry, hidden bugs, and electronic devices, poisons, you name it. Even Julian Assange has weighed in, stating “The diversity of symptoms suggests that this is a pathogen combined with paranoia in an isolated diplomatic corps.”

So what’s going on? Bizarre accidents? Cloak and dagger gone awry? Mass hysteria among the US state department, or something else entirely? Continue reading “Cuban Embassy Attacks And The Microwave Auditory Effect” →