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Tech In Plain Sight: Primitive Engineering Materials

December 22, 2021 by 33 Comments

It isn’t an uncommon science fiction trope for our hero to be in a situation where there is no technology. Maybe she’s back in the past or on a faraway planet. The Professor from Gilligan’s Island comes to mind, too. I’d bet the average Hacakday reader could do pretty well in that kind of situation, but there’s one thing that’s often overlooked: materials. Sure, you can build a radio. But can you make wire? Or metal plates for a capacitor? Or a speaker? We tend to overlook how many abstractions we use when we build. Even turning trees into lumber isn’t a totally obvious process.

People are by their very nature always looking for ways to use the things around them. Even 300,000 years ago, people would find rocks and use them as tools. It wasn’t long before they found that some rocks could shape other rocks to form useful shapes like axes. But the age of engineered materials is much younger. Whether clay, metal, glass, or more obviously plastics, these materials are significantly more useful than rocks tied to sticks, but making them in the first place is an engineering story all on its own.

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Tech In Plain Sight: Eyeglasses

November 16, 2021 by 47 Comments

Glasses wearers, try a little experiment. Take off your glasses and look at this page or, at least, at something you can’t see well without your glasses. Now imagine if you lived in a time where there was nothing to be done about your vision. If you wear contacts or you have good vision — perhaps you had surgery — then congratulations. But for most of us, vision changes with age are a fact of life. Even many young people need glasses or some other intervention to get good eyesight. At first glance, you might think eyeglasses are an obvious invention, but it turns out we didn’t get real glasses for quite some time and modern glasses are truly a piece of high tech that hides — quite literally — right in front of your face.

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Tech In Plain Sight: Air Conditioning

October 27, 2021 by 41 Comments

I’m always amazed that technology can totally wipe out industries. Sure, some people make a living making horseshoes, for example, but the demand for them is way down compared to what it would have been when horses were the normal mode of transportation. But even so, people still make horseshoes. But think about the ice harvesting business. Never heard of it? Turns out, before refrigeration, there was a huge business of moving ice from where it naturally occurred to other places and storing it, usually underground with a lot of insulation. As far as I know, that business — including the neighborhood ice man — is totally gone now except for some historical exhibitions. We take refrigeration and air conditioning for granted, but it hasn’t been that long ago that ice was a luxury and your own reprieve from the heat was a fan.

Early Cooling

The story starts a little earlier than you might expect. In the 1840s, physician John Gorrie was concerned about “the evils of high temperature.” His hospital in Florida imported ice using the aforementioned ice trade and it wasn’t cheap nor was it very effective.

Undeterred, he developed a machine that used a horse, a waterwheel, steam, or wind power to drive a compressor to create ice. He got a patent in 1851 but it failed to catch on before his financial backer died. In fact, Oliver Evans had the idea in 1805 but never built a working machine. Jacob Perkins patented the first compression cooler in 1834, again with little practical use.

When U.S. President Garfield was shot, Navy engineers built a cooling box using cloths soaked in ice water to cool the president’s hospital room by 20 degrees. Since the mortally wounded president survived 80 days after the shooting, we presume he appreciated the comfort.

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Tech In Plain Sight: Glucose Meters

October 20, 2021 by 27 Comments

If you or someone you know is diabetic, it is a good bet that a glucose meter is a regular fixture in your life. They are cheap and plentiful, but they are actually reasonably high tech — well, at least parts of them are.

The meters themselves don’t seem like much, but that’s misleading. A battery, a few parts, a display, and enough of a controller to do things like remember readings appears to cover it all. You wouldn’t be surprised, of course, that you can get the whole affair “on a chip.” But it turns out, the real magic is in the test strip and getting a good reading from a strip requires more metrology than you would think. A common meter requires a precise current measurement down to 10nA. The reading has to be adjusted for temperature, too. The device is surprisingly complex for something that looks like a near-disposable piece of consumer gear.

Of course, there are announcements all the time about new technology that won’t require a needle stick. So far, none of those have really caught on for one reason or another, but that, of course, could change. GlucoWatch G2, for example, was a watch that could read blood glucose, but — apparently — was unable to cope with perspiration.

Even the meters that continuously monitor still work in more or less the same way as the cheap meters. As Hackaday’s Dan Maloney detailed a few years back, continuous glucose monitors leave a tiny sensor under your skin and measure fluid in your body, not necessarily blood. But the way the sensor works is usually the same.

For the purposes of this article, I’m only going to talk about the traditional meter: you insert a test strip, prick your finger, and let the test strip soak up a little bit of blood.

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Bar code shown in a 3D plain in Vaporwave Aesthetic

Tech In Plain Sight: Check Digits And Human Error

August 25, 2021 by 31 Comments

Computers in working order and with correct software don’t make mistakes. People, however, make plenty of mistakes (including writing bad software or breaking computers). In quality circles, there’s a Japanese term, poka yoke, which roughly means ‘error avoidance’. The idea is to avoid errors by making them too obvious for them to occur. For example, consider a SIM card in your phone. The little diagonal corner means it only goes in one way. If you put it in the wrong way, it is obviously wrong.

To be successful at poka yoke, you have to be able to imagine what a user might do wrong and then come up with some way to make it obvious that it is wrong. There are examples of this all around us and we sometimes don’t even know it. For example, what do your credit card number, your car’s VIN code, and a UPC code on a can of beans have in common?

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Tech Hidden In Plain Sight: Cruise Control

July 8, 2021 by 29 Comments

The advent of the microcontroller changed just about everything. Modern gadgets often have a screen-based interface that may hide dozens or hundreds of functions that would have been impractical and confusing to do with separate buttons and controls. It also colors our thinking of what is possible. Imagine if cars didn’t have cruise control and someone asked you if it were possible. Of course. Monitor the speed and control the gas using a PID algorithm. Piece of cake, right? Except cruise control has been around since at least 1948. So how did pre-microcontroller cruise control work? Sure, in your modern car it might work just like you think. But how have we had seventy-plus years of driving automation?

A Little History

A flyball governor from a US Navy training film.

Controlling the speed of an engine is actually not a very new idea. In the early 1900s, flyball governors originally designed for steam engines could maintain a set speed. The idea was that faster rotation caused the balls would spread out, closing the fuel or air valve while slower speeds would let the balls get closer together and send more fuel or air into the engine.

The inventor of the modern cruise control was Ralph Teetor, a prolific inventor who lost his sight as a child. Legend has it that he was a passenger in a car with his lawyer driving and grew annoyed that the car would slow down when the driver was talking and speed up when he was listening. That was invented in 1948 and improved upon over the next few years.

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Tech Hidden In Plain Sight: Gas Pumps

November 12, 2020 by 67 Comments

Ask someone who isn’t technically inclined how a TV signal works or how a cell phone works, or even how a two-way switch in a hall light works and you are likely to get either a blank stare or a wildly improbable explanation. But there are some things so commonplace that even the most tech-savvy of us don’t bother thinking about. One of these things is the lowly gas pump.

Gas pumps are everywhere and it’s a safe bet to assume everyone reading this has used one at some point, most of use on a regular basis. But what’s really going on there?

Most of it is pretty easy to figure out. As the name implies, there must be a pump. There’s some way to tell how much is pumping and how much it costs and, today, some way to take the payment. But what about the automatic shut off? It isn’t done with some fancy electronics, that mechanism dates back decades. Plus, we’re talking about highly combustible materials, there has to be more to it then just a big tank of gas and a pump. Safety is paramount and, experientially, we don’t hear about gas stations blowing up two or three times a day, so there must be some pretty stout safety features. Let’s pay homage to those silent safety features and explore the tricks of the gasoline trade.

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