Home Safety Monitoring With IoT

Home automation is a popular project to undertake but its complexity can quickly become daunting, especially if you go further than controlling a few lights (or if you’re a renter). To test the waters you may want to start with something like this home safety monitor, which is an IoT device based on an Arduino. It allows remote monitoring of a home for things such as temperature, toxic gasses, light, and other variables, which is valuable even if you don’t need or want to control anything.

The device is built around an Arduino Nano 33 IOT which has WiFi and Bluetooth capabilities as well as some integrated security features. This build features a number of sensors including pressure/humidity, a gas/smoke detector, and a light sensor. To report all of the information it gathers around the home, an interface with Ubidots is configured to allow easy (and secure) access to the data gathered by the device.

The PCB and code for the project are all provided on the project page, and there are a number of other options available if Ubidots isn’t your preferred method of interfacing with the Internet of Things. You might even give Mozilla’s WebThings a shot if you’re so inclined.

Fail Of The Week: Thermostat Almost Causes A House Fire

Fair warning: any homeowners who have thermostats similar to the one that nearly burned down [Kerry Wong]’s house might be in store for a sleepless night or two, at least until they inspect and perhaps replace any units that are even remotely as sketchy as what he found when he did the postmortem analysis in the brief video below.

The story begins back in the 1980s, when the Southern New England area where [Kerry] lives enjoyed a housing boom. Contractors rushed to turn rural farmland into subdivisions, and new suburbs crawled across the landscape. Corners were inevitably cut during construction, and one common place to save money was the home’s heating system. Rather than engage an HVAC subcontractor to install a complicated heating system, many builders opted instead to have the electricians install electric baseboards. They were already on the job anyway, and at the time, both copper and electricity were cheap.

Fast forward 40 years or so, and [Kerry] finds himself living in one such house. The other night, upon catching the acrid scent of burning insulation, he followed his nose to the source: a wall-mounted thermostat for his electric baseboard. His teardown revealed burned insulation, bare conductors, and scorched plastic on the not-so-old unit; bearing a 2008 date code, the thermostat must have replaced one of the originals. [Kerry] poked at the nearly combusted unit and found the root cause: the spot welds holding the wires to the thermostat terminal had become loose, increasing the resistance of the connection. As [Kerry] points out, even a tenth of an ohm increase in resistance in a 15 amp circuit would dissipate 20 watts of heat, and from the toasty look of the thermostat it had been a lot more than that.

The corner-cutting of the 1980s was nothing new, of course – remember the aluminum wiring debacle? Electrical fires are no joke, and we’re glad [Kerry] was quick to locate the problem and prevent it from spreading.

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Lessons In Li-Ion Safety

If you came here from an internet search because your battery just blew up and you don’t know how to put out the fire, then use a regular fire extinguisher if it’s plugged in to an outlet, or a fire extinguisher or water if it is not plugged in. Get out if there is a lot of smoke. For everyone else, keep reading.

I recently developed a product that used three 18650 cells. This battery pack had its own overvoltage, undervoltage, and overcurrent protection circuitry. On top of that my design incorporated a PTC fuse, and on top of that I had a current sensing circuit monitored by the microcontroller that controlled the board. When it comes to Li-Ion batteries, you don’t want to mess around. They pack a lot of energy, and if something goes wrong, they can experience thermal runaway, which is another word for blowing up and spreading fire and toxic gasses all over. So how do you take care of them, and what do you do when things go poorly?

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The Blessings And Destruction Wrought By Lead Over Millennia

Everyone one of us is likely aware of what lead — as in the metal — is. Having a somewhat dull, metallic gray appearance, it occupies atomic number 82 in the periodic table and is among the most dense materials known to humankind. Lead’s low melting point and malleability even when at room temperature has made it a popular metal since humans first began to melt it out of ore in the Near East at around 7,000 BC in the Neolithic period.

Although lead’s toxicity to humans has been known since at least the 2nd century BC and was acknowledged as a public health hazard in the late 19th century, the use of lead skyrocketed in the first half of the 20th century. Lead saw use as a gasoline additive beginning in the 1920s, and the US didn’t abolish lead-based paint until 1978, nearly 70 years after France, Belgium and Austria banned it.

With the rise of consumer electronics, the use of lead-based solder became ever more a part of daily life during the second part of the 20th century, until an increase in regulations aimed at reducing lead in the environment. This came along with the World Health Organization’s fairly recent acknowledgment that there is truly no safe limit for lead in the human body.

In this article I’ll examine the question of why we are still using lead, and if we truly must, then how we can use this metal in the safest way possible.

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Ask Hackaday: What Good Is A Robot Dog?

It is said that Benjamin Franklin, while watching the first manned flight of a hot air balloon by the Montgolfier brothers in Paris in 1783, responded when questioned as to the practical value of such a thing, “Of what practical use is a new-born baby?” Dr. Franklin certainly had a knack for getting to the heart of an issue.

Much the same can be said for Spot, the extremely videogenic dog-like robot that Boston Dynamics has been teasing for years. It appears that the wait for a production version of the robot is at least partially over, and that Spot (once known as Spot Mini) will soon be available for purchase by “select partners” who “have a compelling use case or a development team that [Boston Dynamics] believe can do something really interesting with the robot,” according to VP of business development Michael Perry.

The qualification of potential purchasers will certainly limit the pool of early adopters, as will the price tag, which is said to be as much as a new car – and a nice one. So it’s not likely that one will show up in a YouTube teardown video soon, so until the day that Dave Jones manages to find one in his magic Australian dumpster, we’ll have to entertain ourselves by trying to answer a simple question: Of what practical use is a robotic dog?

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Hackaday Links: July 21, 2019

Ordering a PCB used to be a [Henry Ford]-esque experience: pick any color you like, as long as it’s green. We’ve come a long way in the “express yourself” space with PCBs, with slightly less than all the colors of the rainbow available, and some pretty nice silkscreening options to boot. But wouldn’t it be nice to get full-color graphics on a PCB? Australian company Little Bird thinks so, and they came up with a method to print graphics on a board. The results from what looks like a modified inkjet printer are pretty stunning, if somewhat limited in application. But I bet you could really make a splash with these in our Beautiful Hardware contest.

The 50th anniversary of the Apollo 11 landing has come and gone with at least as much fanfare as it deserves. Part of that celebration was Project Egress, creation of a replica of the Columbia crew hatch from parts made by 44 hackers and makers. Those parts were assembled on Thursday by [Adam Savage] at the National Air and Space Museum in an event that was streamed live. A lot of friends of Hackaday were in on the build and were on hand, like [Fran Blanche], [John Saunders], [Sophy Wong], and [Estefannie]. The Smithsonian says they’ll have a recording of the stream available soon, so watch this space if you’re interested in a replay.

From the “Don’t try this at home” department, organic chemist [Derek Lowe] has compiled a “Things I won’t work with” list. It’s real horror show stuff that regales the uninitiated with all sorts of chemical nightmares. Read up on chlorine trifluoride, an oxidizer of such strength that it’s hypergolic with anything that even approaches being fuel. Wet sand? Yep, bursts into flames on contact. Good reading.

Continuing the safety theme, machinist [Joe Pieczynski] offers this lathe tip designed to keep you in possession of a full set of fingers. He points out that the common practice of using a strip of emery cloth to polish a piece of round stock on either a wood or metal lathe can lead to disaster if the ends of the strip are brought into close proximity, whereupon it can catch and act like a strap wrench. Your fingers don’t stand a chance against such forces, so watch out. [Joe] doesn’t share any gory pictures of what can happen, but they’re out there. Only the brave need to Google “degloving injury.” NSFL – you’ve been warned.

On a happier note, wouldn’t it be nice to be able to print water-clear parts on a standard 3D printer? Sure it would, but the “clear” filaments and resins all seem to result in parts that are, at best, clearish. Industrial designer [Eric Strebel] has developed a method of post-processing clear SLA prints. It’s a little wet sanding followed by a top coat of a super stinky two-part urethane clearcoat. Fussy work, but the results are impressive, and it’s a good technique to file away for someday.

Blacksmithing For The Uninitiated: Hammer And Tongs

Regular readers will recognise this as the third part of a series exploring blacksmithing for those who have perhaps always fancied having a go but have never quite known where to start. It’s written from a position of the unusual experience of having grown up around a working forge, my dad may now be retired but he has a blacksmith specialising in architectural ironwork.

So far in this series we’ve looked in detail at the hearth and anvil that you might find in a typical forge, and delivered some pointers as to where you might look to find or even construct your own.Those are the signature pieces of equipment you’ll find in a forge, but with them alone you can still not be a blacksmith.

If I Had A Hammer…

An array of hammers of different weights and types.
An array of hammers of different weights and types.

Given an anvil, a hearth, and a vat of water to quench hot work in, and you’re almost set for your forge, but not quite. Most of a modern blacksmith’s workshop is the standard metalworking assortment of welders and angle grinders, but there is a set of tools that remain essential for blacksmithing alone. Your hammers are what connect you to the work, and can be as individual as the preferences of the blacksmiths themselves. There is no “right” answer to the question of what hammer you should use, instead you should use the one that works best for you. I instinctively favour a round-faced ball-peen hammer  because that’s what my dad mostly used, but for example my Dutch friends use square faced cross-peen hammers. Blacksmiths will often make their own hammers to suit their needs, for example my dad made more than one using the high-quality steel of vehicle half-shafts as a starting point. Hardening them is a specialist skill in its own right, and I remember quite a few experiments before he perfected it.

It may well be stating the obvious, but the weight of the hammer influences how much energy it can impart to the work, and in turn the size of work that can be done. Casting an eye over my dad’s hammers the three workaday weights were 2 pound, 3 pound, and 4 pound (roughly 1 kg, 1.5 kg, and 2 kg), allowing a variety from fine work to heavier hitting of larger pieces. In a recent project, making a mediaeval nail, I selected an unsubtle lump hammer to draw out the larger square stock, and a much smaller one to finish it up, create the fine point, and relatively thin head. These are only a subsection of the hammers at his disposal though, like most blacksmiths he has a variety for all tasks, up to sledgehammers. I have frequently taken my turn either holding a piece with tongs while he used a sledgehammer, or on the sledgehammer myself.

Tongs, for Hot Gripping Moments

A selection of tongs, including some designed for very specific tasks. Our thanks to [Igor Nikolic] for making this picture possible.
A selection of tongs, including some designed for very specific tasks. Our thanks to [Igor Nikolic] for making this picture possible.
The constant companion to a blacksmith’s hammer is a pair of tongs. These can be bought from blacksmith’s suppliers, but making a pair can be a task within the reach of most smiths. Two identical sides are made from pieces of stock, with long thin handles, a flat piece to form the hinge, and whatever jaw piece is required. It feels like cheating to form the hole for the hinge on a drill press rather than on the anvil with a punch, but riveting it with a short piece of bar is a straightforward enough process. Blacksmiths will have a huge array of tongs with different jaws for specific jobs, built up over years as jobs demand it. If you cast your mind back to the Finnish smith pictured halfway down the first installment of this series, you’ll find several racks of tongs. A later episode of this series will look at making a set of tongs, though we can’t promise in advance the quality of the finished article.

Keeping yourself clean, safe, and not on fire

My usual forging attire of steel toecap workboots, spark-resistant overalls, and blacksmith's leather apron. The forge is outside Hack42 hackerspace, Arnhem, and is set up a bit too low for me. Photo: (c) Martina Short, used here with permission.
My usual forging attire of steel toecap workboots, spark-resistant overalls, and blacksmith’s leather apron. The forge is outside Hack42 hackerspace, Arnhem, and the anvil is set up a bit too low for me. Photo: © Martina Short, used here with permission.

A final moment for today should be spent on the subject of protective equipment. The hazards of blacksmithing are relatively uncomplicated, but some basic protective clothing is still very much worth having. The most obvious hazard is heat, you will be working in a noisy environment with red hot metal and fire. Though you will generate fewer sparks than you’d expect, I have a blacksmith’s leather apron and a set of fire-resistant overalls. Both of these are readily available from blacksmith’s supply stores, and are well worth the investment. There are also a lot of heavy and sharp items involved, not to mention hot particles on the floor. For that reason I also have a set of steel-toecapped workboots rated for hot particles. They aren’t the most elegant of footwear, but they have saved me from a few nasty moments.

I do not have any face protection specifically for blacksmithing, but depending on the work in hand there may be some sparks created. A polycarbonate face shield rated for hot particles should be available from any safety equipment supplier, and shouldn’t cost too much, and is an essential thing to own if you are doing any grinding or rotary wire brushing. Beyond that, there are also leather gloves designed for handling hot metal. I don’t use them because I prefer the feel of  the hammer directly and am happy to use a pair of tongs to hold hot pieces of steel.

We’ve taken you through the basic workshop equipment of a blacksmith over the last few episodes of this series, and you should now have a basic idea of the safety kit you would be well advised to own. From this foundation we’ll next take you into the forge and start looking at a few blacksmithing techniques and simple projects, and along the way we’ll see some of the materials involved, too.