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1028 Articles

Set Your Clocks To Decimal Time

December 14, 2016 by 168 Comments

Many stop lights at street intersections display a countdown of the remaining seconds before the light changes. If you’re like me, you count this time in your head and then check how in sync you are. But did you know that if the French had their way back in the 1890s when they tried to introduce decimal time, you’d be counting to a different beat? Did you know the Chinese have used decimal time for millennia? And did you know that you may have unknowingly used it already if you’ve programmed in Linux? Read on to see what decimal time is along with the answers to these questions.

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My Beef With Ham Radio

December 12, 2016 by 373 Comments

My amateur radio journey began back in the mid-1970s. I was about 12 at the time, with an interest in electronics that baffled my parents. With little to guide me and fear for my life as I routinely explored the innards of the TVs and radios in the house, they turned to the kindly older gentleman across the street from us, Mr. Brown. He had the traditional calling card of the suburban ham — a gigantic beam antenna on a 60′ mast in the backyard – so they figured he could act as a mentor to me.

Mr. Brown taught me a lot about electronics, and very nearly got me far enough along to take the test for my Novice class license. But I lost interest, probably because I was an adolescent male and didn’t figure a ham ticket would improve my chances with the young ladies. My ham ambitions remained well below the surface as life happened over the next 40 or so years. But as my circumstances changed, the idea of working the airwaves resurfaced, and in 2015 I finally took the plunge and earned my General class license.

The next part of my ham story is all-too-familiar these days: I haven’t done a damn thing with my license. Oh, sure, I bought a couple of Baofeng and Wouxun handy-talkies and lurked on the local repeaters. I even bought a good, solid HF rig and built some antennas, but I’ve made a grand total of one QSO — a brief chat with a ham in Texas from my old home in Connecticut on the 10-meter band. That’s it.

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You Can Have My LM386s When You Pry Them From My Cold Dead Hands

December 7, 2016 by 137 Comments

Everyone has a chip-of-shame: it’s the part that you know is suboptimal but you keep using it anyway because it just works well enough. Maybe it’s not what you would put into a design that you’re building more than a couple of, but for a quick and dirty lashup, it’s just the ticket. For Hackaday’s [Adam Fabio], that chip is the TIP120 transistor. Truth be told, we have more than one chip of shame, but for audio amplification purposes, it’s the LM386.

The LM386 is an old design, and requires a few supporting passive components to get its best performance, but it’s fundamentally solid. It’s not noise-free and doesn’t run on 3.3 V, but if you can fit a 9 V battery into your project and you need to push a moderate amount of sound out of a speaker, we’ll show you how to get the job done with an LM386.

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Daylight Saving Time – Whys And Why Nots

November 28, 2016 by 87 Comments

We recently went through our twice yearly period of communal venting called adjusting for daylight saving time (DST), or British Summer Time (BST) as it’s called in the UK. But why are we changing the time? Seriously, who caused all this? Does it do any good? Do we still need it? And what can we do about it? As it turns out, most of us want it, as you’ll see below.

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A Rebel Alliance For Internet Of Things Standards

November 21, 2016 by 41 Comments

Back when the original Internet, the digital one, was being brought together there was a vicious standards war. The fallout from the war fundamentally underpins how we use the Internet today, and what’s surprising is that things didn’t work out how everyone expected. The rebel alliance won, and when it comes to standards, it turns out that’s a lot more common than you might think.

Looking back the history of the Internet could have been very different. In the mid eighties the OSI standards were the obvious choice. In 1988 the Department of Commerce issued a mandate that all computers purchased by government agencies should be OSI compatible starting from the middle of 1990, and yet two years later the battle was already over, and the OSI standards had already lost.

In fact by the early nineties the dominance of TCP/IP was almost complete. In January of 1991 the British academic backbone network, called JANET (which was based around X.25 colored book protocols), established a pilot project to host IP traffic on the network. Within ten months the IP traffic had exceeded the levels of X.25 traffic, and IP support became official in November.

“Twenty five years ago a much smaller crowd was fighting about open versus proprietary, and Internet versus OSI. In the end, ‘rough consensus and running code’ decided the matter: open won and Internet won,”

—Marshall Rose, chair of several IETF Working Groups during the period

This of course wasn’t the first standards battle, history is littered with innumerable standards that have won or lost. It also wasn’t the last the Internet was to see. By the mid noughties SOAP and XML were seen as the obvious way to build out the distributed services we all, at that point, already saw coming. Yet by the end of the decade SOAP and XML were in heavy retreat. RESTful services and JSON, far more lightweight and developer friendly than their heavyweight counterparts, had won.

“JSON appeared at a time when developers felt drowned by misguided overcomplicated XML-based web services, and JSON let them just get the job done,”

“Because it came from JavaScript, and pretty much anybody could do it, JSON was free of XML’s fondness for design by committee. It also looked more familiar to programmers.”

—Simon St. Laurent, content manager at LinkedIn and O’Reilly author

Yet, depending on which standards body you want to listen to, ECMA or the IETF, JSON only became a standard in 2013, or 2014, respectively and while the IETF RFC talks about semantics and security, the ECMA standard covers only the syntax. Despite that it’s unlikely many people have actually read the standards, and this includes the developers using the standard and even those implementing the libraries those developers depend on.

We have reached the point where standardization bodies no longer create standards, they formalize them, and the way we build the Internet of Things is going to be fundamentally influenced by that new reality.

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Smartphone Bench Instrument Apps: Disappointment Or Delight?

November 17, 2016 by 24 Comments

If you are interested in electronics or engineering, you’ll have noticed a host of useful-sounding apps to help you in your design and build work. There are calculators, design aids, and somewhat intriguingly, apps that claim to offer an entire instrument on your phone. A few of them are produced to support external third-party USB instrument peripherals, but most of them claim to offer the functionality using just the hardware within the phone. Why buy an expensive oscilloscope, spectrum analyzer, or signal generator, when you can simply download one for free?

Those who celebrate Christmas somewhere with a British tradition are familiar with Christmas crackers and the oft-disappointing novelties they contain. Non-Brits are no doubt lost at this point… the crackers in question are a cardboard tube wrapped in shiny paper drawn tight over each end of it. The idea is that two people pull on the ends of the paper, and when it comes apart out drops a toy or novelty. It’s something like the prize in a Cracker Jack Box.

Engineering-oriented apps follow this cycle of hope and disappointment. But there are occasional exceptions. Let’s tour some of the good and the bad together, shall we?

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Crossing Wheatstone Bridges

November 8, 2016 by 18 Comments

The Wheatstone bridge is a way of measuring resistance with great accuracy and despite having been invented over 150 years ago, it still finds plenty of use today. Even searching for it on Hackaday brings up its use in a number of hacks. It’s a fundamental experimental device, and you should know about it.

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