Minimal MQTT: Power And Privacy

June 2, 2016 by Elliot Williams 43 Comments

In this installment of Minimal MQTT, I’m going to cover two loose ends: one on the sensor node side, and one on the MQTT server side. Specifically, I’ll tackle the NodeMCU’s sleep mode to reduce power and step you through bridging MQTT servers to get your data securely out of your home server and into “the cloud”, which is really just other people’s servers.

If you’re just stepping into this series now, you should really check out the other three posts, where I set up a server, then build up some sensor nodes, and then flesh-out a few ways to control everything from your phone or the web. That’s the coolest material, anyway. This last installment just refines what we’ve built on. Let’s go!

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Tools Of The Trade – Reflow

June 2, 2016 by Bob Baddeley 40 Comments

In our previous issues in this series on making circuit boards, we covered placing solder paste and placing components. Now it’s time to bake our cake!

There are a variety of methods for reflowing a circuit board, but they all rely on a single principle: heat up the solder paste (a mixture of flux and solder) until the flux burns off and the solder becomes liquid, and then cool it down. Accomplishing this once or twice is easy; once you’ve played with a hot plate you’ll swear off through hole. Scaling it up and doing it repeatedly with high yield is extremely challenging, though. Continue reading “Tools Of The Trade – Reflow” →

How Did Pocket NC Survive And Thrive?

June 1, 2016 by Gerrit Coetzee 49 Comments

We had a chance to talk to Matthew Hertel of PocketNC at the Bay Area Maker Faire this year. During the conversation, he answered some questions I’d had about the project since I saw it on Kickstarter, and told a cool story while he was at it.

When the Pocket NC 5-axis Tabletop CNC Mill KickStarter came out, I immediately chocked it up as a failure out of the gate. I figured that there would never be a single delivered unit. It just seemed too impossible. The price was too low for a machine with that many large machined aluminum pieces. It had real linear guides. It had a real spindle and housed a beagle bone black running linuxCNC. It just couldn’t be that cheap. Ends up, I’m quite happy to be wrong. Pocket NC is doing well, delivering their first units, and taking new orders.

The CNC equivalent of a brag track on a hip-hop record.

It’s easy to get jaded with the Kickstarter and IndieGoGo scams that are out there. Or even the disappointing behavior of projects that could be legitimate. People often do failure analysis of companies, but it is also worth investigating what people did right when they are successful.

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Long-Term Review: Weller Magnastat Soldering Iron

June 1, 2016 by Jenny List 47 Comments

One of the things you find yourself doing as a young engineer is equipping yourself with the tools of your trade. These will be the foundations upon which your career is built in a way that a diploma or degree certificate will never be, for the best degree in the world is less useful if the quality of your tools renders you unable to capitalise upon it. You may be lucky enough to make some of them yourself, but others you’ll lust after as unaffordable, then eventually put the boat out a little to buy at the limit of your meager income.

Your bench may have a few of these lifetime tools. They could be something as simple as screwdrivers or you may have one of those indestructible multimeters, but in my case my lifetime tool is my soldering iron. At some time in 1992 I spent about £60($173 back then), a lot of money for a student, on a mains-powered Weller Magnastat. The World Wide Web was still fairly fresh from Tim Berners-Lee’s NeXT in those days, so this meant a trip to my university’s RS trade counter and a moment poring over a telephone-book-sized catalogue before filling in an order slip.

The Magnastat is a simple but very effective fixed-temperature-controlled iron. The tip has a magnet on its rear end which holds closed a power switch for the heating element. When the tip has heated to the Curie temperature of the magnet, it loses its magnetism and the switch opens. The temperature falls to below the Curie temperature and the magnetism returns, the switch closes, the tip warms up again, and the cycle repeats itself. The temperature of the tip is thus dictated by the magnet’s Curie temperature, and Weller provides a range of tips fitted with magnets for different temperatures.

The result is an iron with enough power to solder heat-sucking jobs that would leave lesser irons gasping for juice, while also having the delicacy to solder tiny surface-mount components without destroying them or lifting tracks. It’s not a particularly small or lightweight iron if you are used to the featherlight pencil irons from today’s soldering stations, but neither is it too large or heavy to be unwieldy. In the nearly quarter century I have owned my Magnastat it has had a hand in almost everything I have made, from hi-fi and tube amplifiers through radio transmitters, stripline filters, kits, and too many repairs to mention. It has even been pressed into service plastic-welding a damaged motorcycle fairing. It has truly been a lifetime tool.

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Kids! Don’t Try This At Home! Robot Destroys Mankind

June 1, 2016 by Al Williams 195 Comments

From the Forbin Project, to HAL 9000, to War Games, movies are replete with smart computers that decide to put humans in their place. If you study literature, you’ll find that science fiction isn’t usually about the future, it is about the present disguised as the future, and smart computers usually represent something like robots taking your job, or nuclear weapons destroying your town.

Lately, I’ve been seeing something disturbing, though. [Elon Musk], [Bill Gates], [Steve Wozniak], and [Stephen Hawking] have all gone on record warning us that artificial intelligence is dangerous. I’ll grant you, all of those people must be smarter than I am. I’ll even stipulate that my knowledge of AI techniques is a little behind the times. But, what? Unless I’ve been asleep at the keyboard for too long, we are nowhere near having the kind of AI that any reasonable person would worry about being actually dangerous in the ways they are imagining.

Smart Guys Posturing

Keep in mind, I’m interpreting their comments as saying (essentially): “Soon machines will think and then they will out-think us and be impossible to control.” It is easy to imagine something like a complex AI making a bad decision while driving a car or an airplane, sure. But the computer that parallel parks your car isn’t going to suddenly take over your neighborhood and put brain implants in your dogs and cats. Anyone who thinks that is simply not thinking about how these things work. The current state of computer programming makes that as likely as saying, “Perhaps my car will start flying and we can go to Paris.” Ain’t happening.

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How To Fail At Laser Cutting

May 31, 2016 by Donald Papp 64 Comments

Laser cutters are CNC power tools, which means an operator uploads a job digitally and then pushes START to let the machine do all the work while they lie back in a hammock sipping a margarita, occasionally leaping out in a panic because the sound coming from the machine changed slightly.

Like other power tools, laser cutters are built around doing one thing very well, but they require an operator’s full attention and support. The operator needs to handle all the other things that go on before, during, and after the job. It’s not too hard to get adequate results, but to get truly professional and repeatable ones takes work and experience and an attention to detail.

People often focus on success stories, but learning from failures is much more educational. In the spirit of exploring that idea, here are my favorite ways to fail at laser cutting and engraving. Not all of these are my own personal experience, but they are all someone’s personal experience.

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Path To Craftsmanship: The Art Of Throwing It Away

May 31, 2016 by Gerrit Coetzee 154 Comments

Some hackers build sharp, mildly toxic nests of parts, components, and thrifty finds around themselves. These nests, while not comfortable, are certainly comforting. They allow the hacker’s psyche to inhabit a locale as chaotic as their minds. Within these walls of stuff and clutter, stunning hacks pour out amid a small cloud of cursing. This article is not for them.

http://www.computerhistory.org/atchm/an-analog-life-remembering-jim-williams/ — Very few of us can actually function in a workplace such like that of the venerable Jim Williams (photo from linked article). Thanks to the commenters for mentioning him in the previous article.

For the rest of us, clutter is a Zen destroying, seemingly unconquerable, monster that taunts our poor discipline and organizational skill from the dark corner of our minds. However, there is an easy solution that is oft overlooked. Somewhat obviously, most organization problems can be solved by simply not having things to organize.

It’s taken me a very long time to realize the source of my clutter woes. My first tactic was to blame myself for my inability to keep up with the mess. A more superior human would certainly be able to use their effortless discipline to keep a space organized. However, the clutter was a symptom of a problem completely separate from my actual ability to keep a space clean.

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