Tech In Plain Sight: Tasers Shooting Confetti

October 16, 2024 by Al Williams 40 Comments

One of the standard tropes in science fiction is some kind of device that can render someone unconscious — you know, like a phaser set to stun. We can imagine times when being aggressively knocked out would lead to some grave consequences, but — we admit — it is probably better than getting shot. However, we don’t really have any reliable technology to do that today. However, if you’ve passed a modern-day policeman, you’ve probably noticed the Taser on their belt. While this sounds like a phaser, it really isn’t anything like it. It is essentially a stun gun with a long reach thanks to a wire with a dart on the end that shoots out of the gun-like device and shocks the target at a distance. Civilian Tasers have a 15-foot long wire, while law enforcement can get longer wires. But did you know that modern Tasers also fire confetti?

It sounds crazy, and it isn’t celebratory. The company that makes the Taser — formerly, the Taser company but now Axon — added the feature because of a common complaint law enforcement had with the device. Interestingly, many things that might be used in comitting a crime are well-understood. Ballistics can often identify that a bullet did or did not come from a particular weapon, for example. Blood and DNA on a scene can provide important clues. Even typewriters and computer printers can be identified by variations in their printing. But if you fire a taser, there’s generally little evidence left behind.

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Tech In Plain Sight: Speedometers

August 22, 2024 by Al Williams 29 Comments

In a modern car, your speedometer might look analog, but it is almost certainly digital and driven by the computer that has to monitor all sorts of things anyway. But how did they work before your car was a rolling computer complex? The electronic speedometer has been around for well over a century and, when you think about it, qualifies as a technlogical marvel.

If you already know how they work, this isn’t a fair question. But if you don’t, think about this. Your dashboard has a cable running into it. The inner part of the cable spins at some rate, which is related to either the car’s transmission or a wheel sensor. How do you make a needle deflect based on the speed?

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Tech In Plain Sight: Escalators

January 29, 2024 by Al Williams 36 Comments

If you are designing a building and need to move many people up or down, you probably will at least consider an escalator. In fact, if you visit most large airports these days, they even use a similar system to move people without changing their altitude. We aren’t sure why the name “slidewalk” never caught on, but they have a similar mechanism to an escalator. Like most things, we don’t think much about them until they don’t work. But they’ve been around a long time and are great examples of simple technology we use so often that it has become invisible.

Of course, there’s always the elevator. However, the elevator can only service one floor at a time, and everyone else has to wait. Plus, a broken elevator is useless, while a broken escalator is — for most failures — just stairs.

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Tech In Plain Sight: Skyscrapers

October 11, 2023 by Al Williams 3 Comments

It is hard to imagine that for thousands of years, the Great Pyramid of Giza was the tallest manmade structure in the world. However, like the Lincoln Cathedral and the Washington Monument, which also held that title, these don’t count as skyscrapers because they didn’t provide living or working space to people. But aside from providing living, retail, or office space, skyscrapers also share a common feature that explains why they are even possible: steel frame construction.

Have you ever wondered why pyramids appear in so many ancient civilizations? The answer is engineering. You build something. Then, you build something on top of it. Then you repeat. It just makes sense. But each upper layer adds weight to all the lower layers, so you must keep getting smaller. Building a 381-meter skyscraper like the Empire State Building using self-supporting walls would mean the ground floor walls would be massive. Steel lets you get around this.

In Antiquity

You might think of high-rise buildings as a modern thing, but that’s actually not true. People seem to have built up to the best of their abilities for a very long time. Some Roman structures were as high as ten stories. Romans built so high that Augustus even tried to limit building height to 25 meters — probably after some accidents. In the 12th century, Bologna had as many as 100 towers, one nearly 100 meters tall.

There are many other examples, including mudbrick structures rising 30 meters in Yemen and 11th-century Egyptian structures rising 14 stories. In some cases, building up was due to the cost or availability of property. In others, it was to stay inside a defensive wall. But whatever the reason, self-supporting walls can only go so high before they are impractical.

So steel and iron frames grabbed the public’s attention with things like Joseph Paxton’s Crystal Palace in 1851, and Gustav Eiffel’s Tower in 1887.

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Tech In Plain Sight: Microwave Ovens

September 26, 2023 by Al Williams 31 Comments

Our homes are full of technological marvels, and, as a Hackaday reader, we are betting you know the basic ideas behind a microwave oven even if you haven’t torn one apart for transformers and magnetrons. So we aren’t going to explain how the magnetron rotates water molecules to produce uniform dielectric heating. However, when we see our microwave, we think about two things: 1) this thing is one of the most dangerous things in our house and 2) what makes that little turntable flip a different direction every time you run the thing?

First, a Little History

Westinghouse Powercaster which could, among other things, toast bread in six seconds

People think that Raytheon engineer Percy Spenser, the chief of their power tube division, noticed that while working with a magnetron he found his candy bar had melted. This is, apparently, true, but Spenser wasn’t the first to notice. He was, however, the first to investigate it and legend holds that he popped popcorn and blew up an egg on a colleague’s face (this sounds like an urban legend about “egg on your face” to us). The Raytheon patent goes back to 1945.

However, cooking with radio energy was not a new idea. In 1933, Westinghouse demonstrated cooking foods with a 10 kW 60 MHz transmitter (jump to page 394). According to reports, the device could toast bread in six seconds. The same equipment could beam power and — reportedly — exposing yourself to the field caused “artificial fever” and an experience like having a cocktail, including a hangover on overindulgence. In fact, doctors would develop radiothermy to heat parts of the body locally, but we don’t suggest spending an hour in the device.

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Tech In Plain Sight: Rain-Sensing Wipers

August 25, 2022 by Al Williams 37 Comments

While it is definitely a first-world problem that you don’t want to manually turn on your windshield wipers when it starts raining, it is also one of those things that probably sounds easier to solve than it really is. After all, you can ask a four-year-old if it is raining and expect a reasonable answer. But how do you ask that question of a computer? Especially a tiny cheap computer that is operating pretty much on its own.

You might want to stop here and try to think of how you’d do it. Measure the conductivity of the glass? Maybe water on the glass affects its dielectric constant and you could measure the resulting capacitance? Modern cars don’t do either. The problem is complicated because you need a solution that works with the glass and isn’t prone to false positives due to dirt or debris.

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Tech In Plain Sight: Fire Hydrants

July 19, 2022 by Al Williams 42 Comments

You probably see them so often that you don’t even notice they are there. Fire hydrants are one of those things that aren’t interesting until you need them, but then they are of paramount importance. You sometimes hear them called fireplugs and it made us wonder what was a plug about it. Perhaps it was because that’s where you plug in your hose? Turns out, no. The real story is much stranger. Not to mention, did you know that there are even “dry” fire hydrants?

Apparently, in the 16th century, water mains were made of wood. When there was a fire, a team would dig the cobblestones out to expose the wooden mains and cut a hole to make an ad hoc well to fill buckets or to pump. Of course, after the fire, you had to repair the mains and that was done with a plug. The city would keep a record of plugs so that if a fire was nearby in the future, you could just “pull the plug” instead of making a new hole.

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