Tech In Plain Sight: What Does A Yellow Light Mean?

Ghigleri’s traffic light

The traffic light is a ubiquitous feature of modern life and is quite old — dating back to 1868 London, although that device was a modified railroad semaphore operated by a policeman, but it was the same idea. The initial test of the signal proved disastrous.

The semaphore had gas lamps to illuminate the signs in the dark. A gas leak caused one of the lamps to explode, badly burning the operator and ending the nascent invention for a while. In 1910, American inventor Ernest Sirrine worked out an automatically controlled traffic signal. Two years later, Lester Wire, a police officer, developed a different version powered by overhead trolley wires to light the signal. A 1917 patent by William Ghiglieri also had two lights — red and green. But where was the yellow light?

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A Brief History Of Weather Control

It used to be a common expression to say that something would happen when “people walked on the moon.” That is, something that was never going to happen. Of course, by 1960, it was clear that someone was going to walk on the moon eventually. There were many other things everyone “knew” would happen in the future. Some of them came true, but many of them didn’t. Some, like video phones and robot factory workers, came true in a way, but not as people imagined. For example, people were confident that computers would easily translate between human languages, something we still have trouble doing entirely reliably. Another standard prediction is that people would control the weather.

Controlling the weather, in some ways, seems even less likely than walking on the moon. After all, we know where the moon is and where it will be. We still don’t understand precisely what causes the weather to behave the way it does. We have models and plenty of scientific theories. But you still can’t know exactly what’s going to happen, where, or when.

History

If you farm or live in a hut, weather is especially important. You want rain but not too much rain. Without scientific knowledge, many cultures had rain-making superstitions like a rain dance or other rituals meant to encourage rain. Some think that loud noises like cannon fire prevent hail.  Charlatans would promise rain in exchange for donations.

However, science would eventually surface, and in the 1800’s James Espy — the first U.S. meteorologist — theorized that convection was what really caused rain. He had bold plans to set massive fires to encourage rain but could not convince Congress to go along.

Half a century later, Robert St. George Dyrenforth tested the effect of explosions on rainfall. There is no evidence that his cannon and fireworks did anything. He did, however, claim credit for any rain that happened to occur nearby. There have been many reports that explosions cause rain — rain often falls after a heated battle, apparently.  The government in Thailand tried to induce rain using dry ice flakes dropped into clouds with, reportedly, some success. Abu Dhabi, Russia, and China’s governments claim to have working weather control today.

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3D Printed Stamp Rollers

If you have an artistic bent, you might have seen self-inking stamp rollers. These are like rotary rubber stamps that leave a pattern as you roll across a page. [Becky] wanted a larger custom roller and turned to 3D printing to make it happen. The first prototype used a modified Sharpie. However, she soon moved to an unmodified acrylic marker that had a rectangular tip.

A Tinkercad design produces a cap that fits the marker and a wheel that contains the desired pattern. Text works well, although you can easily do a custom pattern, too, of course.

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General Instruments Video Game Chip Rides Again

Early video games like Pong were not computer-controlled. They used discrete logic to generate the TV signals. As you might expect, the market exploded when you could get all the logic on a chip. Many of those games used the General Instrument AY-3-8500-1 chip, and [Jeff Tranter] shows us the chip and the many different yet similar games it could play. You can check out the retro gameplay in the video below.

These were marvels of their day, although, by today’s standards, they are snoozers. All the games were variations on a theme. A ball moved and hit paddles, walls, or goals. A few available light gun games were rarely seen in the wild because they took extra components.

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Data Science The Stanford Way

Data science is a relatively new term for a relatively old discipline. Essentially, it is data analysis, particularly for large data sets. It involves techniques as wide-ranging as statistics, computer science, and information theory. What to know more? Stanford has a “Data Science Handbook” that you can read online.

Topics range from how to design a study and create an analytic plan to how to do data visualization, summarization, and analysis. The document covers quite a bit but is very concise.

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A Classic Shortwave Radio Restored

Before the Internet, if you wanted to hear news from around the world, you probably bought a shortwave receiver. In the golden age of world band radio, there was a great deal of high-quality programming on the shortwave bands and a large variety of consumer radios with shortwave bands. For example, the Sony CRF-160 that [M Caldeira] is restoring dates from the late 1960s or early 1970s and would have been a cool radio in its day. It retailed for about $250 in 1972, which sounds reasonable, but — don’t forget — in 1972 that would have been a 10% downpayment on a new car or enough to buy a Big Mac every day for a year with change left over.

As you can see in the video below, the radio seemed to work well right out of the gate, but the radio needed some rust removal and other sprucing up. However, it is an excellent teardown, with some tips about general restoration.

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Ham Radio Memes In The 1970s

If you have a fondness for old and unusual ham gear, [Saveitforparts] has a great video (see below) about a Robot slow scan receiver he found at a junk store.  Slow scan or SSTV is a way to send pictures via low-bandwidth audio, such as you often find on the ham bands. The idea is you take a picture, send some squeaks and blips over the air, and in about 8 or 10 seconds, a single frame of video shows up at the receiver. Hams aren’t the only ones who used it. The Apollo missions used an SSTV system in some cases, too.

I’ve been a ham radio operator for a very long time. When I first heard about SSTV, I thought it sounded cool that you could be talking to someone and then show them a picture of your station or your dog or your kids. But when I looked into it, the reality was far different. In the pre-internet days, SSTV-equipped hams hung out on a handful of watering hole frequencies and basically just sent memes and selfies to each other. Everyone would take turns, but there wasn’t really any conversation.

This actually still goes on, but the hardware isn’t a big deal anymore. The Robot in the video had to decode the signal from audio and store the image somehow. On old gear — some of it homebrew — it was simply persistent phosphor that would eventually fade, but, of course, eventually, images were stored in some form of digital memory. These days, you are likely to use a PC soundcard to both send and receive the necessary audio.

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