Home Automation: Evolution of a Term

Home automation: for me the term recalls rich dudes in the ’80s who could turn off their garage lights with remote-control pads. The stereotype for that era was the more buttons your system had—even non-enabled ones—the more awesome it was, and by extension any luxury remote control had to be three times the size of any TV remote.

And it was a luxury–the hardware was expensive and most people couldn’t justify it. Kind of like the laser-disc player of home improvements. The technology was opaque to casual tinkering, it cost a lot to buy, and also was expensive to install.

The richie-rich stereotypes were reinforced with the technology seen in Bond movies and similar near-future flicks. Everything, even silly things, is motorized, with chrome and concrete everywhere. You, the hero, control everything in the house in the comfort of your acrylic half-dome chair. Kick the motorized blinds, dim the track lighting, and volume up the hi-fi!

This Moonraker-esque notion of home automation turned out to be something of a red herring, because home automation stopped being pretty forever ago; eventually it became available to everyone with a WiFi router in the form of Amazon Echo and Google Nest.

But the precise definition of the term home automation remains elusive. I mean, the essence of it. Let’s break it down.

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Earth Ground And The Grid

The electrical grid transmits power over wires to our houses, and our Bryan Cockfield has covered it very well in his Electrical Grid Demystified series, but what part does the earth ground play? It’s commonly known to be used for safety, but did you know that in some cases it’s also used for power transmission?

Typical House Grounding System

Grounding system normal case
Grounding system normal case

A pretty typical diagram for the grounding system for a house is shown here, along with a few of the current carrying conductors commonly called live and neutral. On the far left is the transformer outside the house and on the far right is an appliance that’s plugged in. In between them is a breaker panel and a wall socket of the style found in North America. The green dashed line shows the normal path for current to flow.

Notice the grounding electrodes for making an electrical connection with the earth ground. To use the US National Electrical Code (NEC) as an example, article 250.52 lists eight types of grounding electrodes. One very good type is an electrode encased in concrete since concrete continues to draw moisture from the ground and makes good physical contact due to its weight. Another is a grounding rod or pipe at least eight feet long and inserted deep enough into the ground. By deep enough, we mean to include factors such as the fact that the frost line doesn’t count as a good ground since it has a high resistance. You have to be careful of using metal water pipes that seemingly go into the ground, as sections of these are often replaced with non-metallic pipes during regular maintenance.

Notice also in the diagram that there are places where the various metal cases are connected to the grounding system. This is called bonding.

Now, how does all this system grounding help us? Let’s start with handling a fault.

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Review: TS100 Soldering Iron

Temperature-controlled soldering irons can be cheap, lightweight, and good. Pick any two of those attributes when you choose an iron, because you’ll never have all three. You might believe that this adage represents a cast-iron rule, no iron could possibly combine all three to make a lightweight high-performance tool that won’t break the bank! And until fairly recently you’d have had a point, but perhaps there is now a contender that could achieve that impossible feat.

The Miniware TS100 is a relatively inexpensive temperature-controlled soldering iron from China that has made a stealthy entry to the market, and which some online commentators claim to be the equal of far more expensive professional-grade irons. We parted with just below £50 (around $60) to place an order for a TS100, and waited for it to arrive so we could see what all the fuss was about.

Constituent parts of a TS100 iron.
Constituent parts of a TS100 iron.

The Goods

The iron arrived well-packaged in a smart cardboard container that was well up to the task of protecting it through international air mail. Nestled in foam were the iron handle, a single combined element and bit, and an envelope containing a short instruction leaflet and a click-seal bag with an Allen key and a spare screw to secure the bit. There was no power supply, you supply your own 12 to 24 V DC to power it.

The handle is a plastic wand containing the temperature control electronics about 100 mm (4″) long, and similar in girth to a chunky fountain pen. At its rear is a barrel socket for the DC supply alongside a micro-USB socket for firmware and configuration, on its top are a small OLED display and a couple of buttons, and at its front is a receptacle for the element unit. Meanwhile the element unit is about 105 mm (3.15″) long, with an exposed length to the end of the bit of about 70 mm (2.75″).

The assembled TS100 iron
The assembled TS100 iron

Assembling the iron is simple enough, the element slots into the receptacle and an Allen screw is tightened to hold it in place. The whole assembled unit weighs 30 g, or a shade over an ounce, and has a balance point almost at its centre.

We hadn’t ordered a power supply with our TS100, but you will doubtless be able to buy one if you don’t have one of the right power level and polarity to hand. We used a 19.5 V netbook supply which was far more than capable of delivering the 40 W the instruction leaflet claims for the iron at 19 V. Maximum power is given as 65 W when supplied with 24 V, while minimum is 17 W with 12 V.

In the hand, the iron is light and easy on the fingers. On its own it is similar in weight and feel to holding a fountain pen, and it is easy to see where comparisons with more expensive irons from the likes of Weller come from. However the iron itself is not the whole story, because your choice of power supply and in particular its lead will make a huge difference to how it feels in practice. The Weller will come fitted with an extra-flexible silicone lead probably designed to work at higher temperatures, by comparison the lead on a cheap power supply is likely to be a stiffer and cheaper affair. Our netbook supply had a right-angled plug, and though it wasn’t a nice flexible silicone cable it turned out not to be a significant burden once it was ensured to be out of range of the hot end.

The TS100 ready to use
The TS100 ready to use

Heating up, the TS100 may not be as quick as some irons, but it’s no slouch. It’s quoted as 15 seconds to 300 Celsius at 19 volts in its instruction leaflet, and our iron certainly didn’t disappoint. Setting the temperature is a simple case of using the buttons to move the temperature up and down on the OLED display, and once it remains at a particular temperature it stores that setting in its non-volatile memory.

In Test

To test the iron we assembled a little radio kit, a surface mount design intended for first-time surface mount solderers and thus using fairly substantial 1206 components and SOICs rather than SOPs or smaller integrated circuits. We found the iron perfectly easy to use, but with one caveat: the stock bit is a pencil tip, type “B2” that is fine for the larger surface mount devices but which would in our opinion probably be a little unwieldy for anything smaller than an 0805. Fortunately there is a large range of other bits of all shapes and sizes for the iron, including one with a finer point that surface-mount wizards may want to look at.

One of the features of the TS100 is that its firmware can be easily upgraded over USB, and to that end it is easy to download the latest version and install it. Simply hold down one of the buttons on live USB plug-in to enter firmware upgrade mode, and when it appears as a drive on the computer into which you’ve plugged it, copy the firmware file to the drive and it upgrades itself.

Unfortunately, in our case the curse of the firmware upgrade struck us, and after downloading and unpacking the file we were unable to make our iron accept it. We can confirm that the process failed for us on Ubuntu, Windows, and MacOS computers, so maybe it just wasn’t our lucky day. Fortunately the TS100 is not one of those devices that is easily bricked by a failed firmware upgrade, so we were simply presented with an error file rather than a dead iron. A soldering iron is in essence a hardware device not a software one, and the shipped firmware version is fine for soldering, so that’s what we’re reviewing.

It’s worth pointing out here that the TS100 firmware is billed as open-source, and that the code and schematics are available from the link above. We say billed as open-source though, because while the code is officially freely available it does not seem to be accompanied by any form of open-source licence. This may be of more concern to software libre purists than many readers, but still, it is worth mentioning.

The TS100 config file
The TS100 config file

We’re told that the latest versions of the firmware provide adjustment of the iron parameters other than temperature through a menu system on the device itself, but on our model the older firmware requires the editing of a text file that appears in a drive when you plug the iron’s USB port into a computer without holding a button down to enter firmware upgrade mode. In the file you can find settings for the different temperatures and timings, and adjust them to your taste.

The Bottom Line

After having the TS100 for a few weeks, what’s our verdict? Is it a good iron, does it give those expensive irons a run for their money, and would we recommend that you consider one?

It’s important to consider the soldering iron market as a whole when answering those questions. If you spend a four-figure sum on a soldering station, you will find yourself with an iron that is lighter than the TS100, it will have a shorter reach, a quicker warm-up time, better software control, more available bits, in fact it will beat the TS100 in every way possible. You’ll be using that soldering station hard every day for a decade, and it will still deliver the goods.

If however you spend a low three-figure sum on a soldering station from a quality manufacturer, you’ll get something closer. It’ll probably have a similar choice of bits and a nice extra-flexible silicone cable, and it will probably last longer, but in soldering terms it will be a surprisingly similar experience. Even having to spend a few more dollars on a power supply, a decent soldering station in this range will still cost you over twice as much as the TS100.

At the same price range or lower as the TS100 it’s likely that soldering stations will start to decrease in quality, be from anonymous manufacturers with no replacement bit support, and not have quite such a good user experience. Perhaps an all-in-one iron for a similar price such as the Antex TCS50 we reviewed earlier in the year is a better comparison, and at this point we start to see how the TS100 is redefining this sector. The Antex is a good iron for everyday soldering, it is the same weight as the TS100 and has the same reach. It’s mains-powered and comes with an extra-flexible silicone cable, but when you compare the irons side-by-side it becomes obvious that the Antex is being left behind. Its handle is huge by comparison, and its temperature control is limited to a very basic up/down setting with no configurability.

So if you are a high-end professional user looking for an iron to work with every day, the TS100 is probably not a choice that will displace your top-of-the-range model. But if you are a regular solderer or serious electronics hobbyist who is looking for the best bang for buck, you should definitely consider one as an alternative to a low-end soldering station. And if you are buying at the bottom of the temperature-controlled iron food chain then you should really give the TS100 a serious look. Returning to our point at the start of this review, it’s cheap, lightweight, and certainly good enough.

Meanwhile if you manufacture soldering irons, this one will probably have you worried. We look forward to seeing what the models produced to compete with it have to offer.

The Miniware TS100 soldering iron, along with associated bits and power supplies, can be found online from all the usual vendors of Chinese electronics.

Serious DX: The Deep Space Network

Humanity has been a spacefaring species for barely sixty years now. In that brief time, we’ve fairly mastered the business of putting objects into orbit around the Earth, and done so with such gusto that a cloud of both useful and useless objects now surrounds us. Communicating with satellites in Earth orbit is almost trivial; your phone is probably listening to at least half a dozen geosynchronous GPS birds right now, and any ham radio operator can chat with the astronauts aboard the ISS with nothing more that a $30 handy-talkie and a homemade antenna.

But once our spacecraft get much beyond geosynchronous orbit, communications get a little dicier. The inverse square law and the limited power budget available to most interplanetary craft exact a toll on how much RF energy can be sent back home. And yet the science of these missions demands a reliable connection with enough bandwidth to both control the spacecraft and to retrieve its precious cargo of data. That requires a powerful radio network with some mighty big ears, but as we’ll see, NASA isn’t the only one listening to what’s happening out in deep space. Continue reading “Serious DX: The Deep Space Network”

Books You Should Read: The Idea Factory

You’ve heard of Bell Labs, but likely you can’t go far beyond naming the most well-known of discoveries from the Lab: the invention of the transistor. It’s a remarkable accomplishment of technological research, the electronic switch on which all of our modern digital society has been built. But the Bell Labs story goes so far beyond that singular discovery. In fact, the development of the transistor is a microcosm of the Labs themselves.

The pursuit of pure science laid the foundation for great discovery. Yes, the transistor was conceived, prototyped, proven, and then reliably manufactured at the Labs. But the framework that made this possible was the material researchers and prototyping ninjas who bridged the gap between the theory and the physical. The technology was built on what is now a common material; semiconducting substances which would not have been possible without the Labs refinement of the process for developing perfectly pure substances reliably doped to produce the n-type and p-type substances that made diode and transistor possible.

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Beyond a Boot Print: The Lasting Effect of Apollo on Humanity

July 20th, 1969 was the day that people from Earth set foot on different soil for the first time. Here we are 48 years later, and the world’s space programs are — well — not very close to returning to the moon. If you aren’t old enough to remember, it was really amazing. The world was in a lot of turmoil in the 1960s (and still is, of course) but everyone stopped to look at the sky and listen to the sound of [Neil Armstrong] taking that first step. It was shocking in a good way and almost universally observed. Practically everyone in the world was focused on that one event. You can see some of that in the NASA video, below.

Space flight was an incredible accomplishment, but it paled in comparison with the push to actually landing a person on the moon and bringing them home safely. The effort is a credit to the ability of people to work together (on the order of thousands of minds) to overcome a difficult challenge. We can learn a lot from that alone, and it makes a compelling argument to continue taking on tough problems. Today, as we remember the Apollo landings, let’s take a moment to recognize what came of it beyond an iconic boot-print in the floury lunar soil.

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The 4-20 mA Current Loop

The I/O capabilities built into most microcontrollers make it easy to measure the analog world. Say you want to build a data logger for temperature. All you need to do is get some kind of sensor that has a linear voltage output that represents the temperature range you need to monitor — zero to five volts representing 0° to 100°C, perhaps. Hook the sensor up to and analog input, whip up a little code, and you’re done. Easy stuff.

Now put a twist on it: you need to mount the sensor far from the microcontroller. The longer your wires, the bigger the voltage drop will be, until eventually your five-volt swing representing a 100° range is more like a one-volt swing. Plus your long sensor leads will act like a nice antenna to pick up all kinds of noise that’ll make digging a usable voltage signal off the line all the harder.

Luckily, industrial process engineers figured out how to deal with these problems a long time ago by using current loops for sensing and control. The most common standard is the 4-mA-to-20-mA current loop, and here we’ll take a look at how it came to be, how it works, and how you can leverage this basic process control technique for your microcontroller projects.

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