Unintentional Emissions

October 1, 2022 by Elliot Williams 40 Comments

First, it was the WiFi router: my ancient WRT54G that had given me nearly two decades service. Something finally gave out in the 2.4 GHz circuitry, and it would WiFi no more. Before my tears could dry, our thermometer went on the fritz. It’s one of those outdoor jobbies that transmits the temperature to an indoor receiver. After that, the remote for our office lights stopped working, but it was long overdue for a battery change.

Meanwhile, my wife had ordered a new outdoor thermometer, and it too was having trouble keeping a link. Quality control these days! Then, my DIY coffee roaster fired up once without any provocation. This thing has worked quasi-reliably for ten years, and I know the hardware and firmware as if I had built them myself – there was no way one of my own tremendously sophisticated creations would be faulty. (That’s a joke, folks.) And then the last straw: the batteries in the office light remote tested good.

We definitely had a poltergeist, a radio poltergeist. And the root cause would turn out to be one of those old chestnuts from the early days of CMOS ICs – never leave an input floating that should have a defined logic level. Let me explain.

The WRT54G was the hub of my own home automation system, an accretion of ESP8266 and other devices that all happily speak MQTT to each other. When it went down, none of the little WiFi nodes could boot up right. One of them, described by yours truly in this video, is an ESP8266 connected to a 433 MHz radio transmitter. Now it gets interesting – the thermometers and the coffee roaster and the office lights all run on 433 MHz.

Here’s how it went down. The WiFi-to-433 bridge failed to connect to the WiFi and errored out before the part of the code where it initialized GPIO pins. The 433 MHz transmitter was powered, but its digital input was left flopping in the breeze, causing it to spit out random data all the time, with a pretty decent antenna. This jammed everything in the house, and apparently even once came up with the command to turn on the coffee roaster, entirely by chance. Anyway, unplugging the bridge fixed everything.

This was a fun one to troubleshoot, if only because it crossed so many different devices at different times, some homebrew and some commercial, and all on different control systems. Until I put it together that everything on 433 MHz was failing, I hadn’t even thought of it as one event. And then it turns out to be a digital electronics classic – the dangling input!

Anyway, hope you enjoyed the ride. And spill some copper for the humble pull-down resistor.

A Love Letter To Small Design Teams, And The B-52

September 22, 2022 by Al Williams 61 Comments

The true measure of engineering success — or, at least, one of them — is how long something remains in use. A TV set someone designed in 1980 is probably, at best, relegated to a dusty guest room today if not the landfill. But the B-52 — America’s iconic bomber — has been around for more than 70 years and will likely keep flying for another 30 years or more. Think about that. A plane that first flew in 1952 is still in active use. What’s more, according to a love letter to the plane by [Alex Hollings], it was designed over a weekend in a hotel room by a small group of people.

A Successful Design

One of the keys to the plane’s longevity is its flexibility. Just as musicians have to reinvent themselves if they want to have a career spanning decades, what you wanted a bomber to do in the 1960s is different than what you want it to do today. Oddly enough, other newer bombers like the B-1B and B-2 have already been retired while the B-52 keeps on flying.

Continue reading “A Love Letter To Small Design Teams, And The B-52” →

Floppy Disk Sings: I’m Big In Japan

September 13, 2022 by Al Williams 66 Comments

The other day, a medical office needed my insurance card. I asked them where to e-mail it and they acted like I had offered them human flesh as an appetizer. “We don’t have e-mail! You have to bring it to us in person!” They finally admitted that they could take a fax and I then had to go figure out how to get a free one page fax sent over the Internet. Keep in mind, that I live in the fourth largest city in the United States — firmly in the top 100 largest cities in the world. I’m not out in the wilderness dealing with a country doctor.

I understand HIPAA and other legal and regulatory concerns probably inhibit them from taking e-mail, but other doctors and health care providers have apparently figured it out. But it turns out that the more regulations are involved in something, the more behind-the-times it is likely to be.

Continue reading “Floppy Disk Sings: I’m Big In Japan” →

Backup Camera, Digital Dash, Road Assist… In 1969?

August 31, 2022 by Al Williams 65 Comments

If your friend told you their car had a backup camera, a digital dashboard, climate control, could scan for radio stations, and even helped stay on the road, you wouldn’t think much about it. Unless the year was 1969. The car — the Hurricane by Australian automaker Holden — was never a production vehicle. But it was way beyond the state of the art in 1969 and isn’t too dated, even today. The concept car was actually found in 1988 and restored by 2011. Honestly, it still looks great.

The car looks amazing and was meant to be a research vehicle and — probably — nice eye candy for the car shows. Seating two passengers with a mid-mounted 253 cubic inch V8, it featured many things we take for granted now: a backup camera, temperature control, and a (somewhat) digital dashboard, for example. There was a system to help it stay in lane, but that required magnets in the road — it was 1969, after all.

The fiberglass body was unique and had a canopy instead of doors. The power seats lifted up when the canopy came up and went down for driving. The passenger compartment was a steel cage. The vehicle featured headrests, a foam-lined fuel tank, and a fire warning system. Two of the brakes were even oil-cooled.

Continue reading “Backup Camera, Digital Dash, Road Assist… In 1969?” →

AI Creates Your Spreadsheets, Sometimes

August 9, 2022 by Al Williams 9 Comments

We’ve been interested in looking at how AI can process things other than silly images. That’s why the “Free AI Bot that Generates the Excel Formula for Any Problem” caught our eye. Based on GPT-3, it supposedly transforms your problem description into a formula suitable for Excel or Google Sheets.

Our first prompt didn’t work out very well. But that was sort of our fault. When they say “Excel formula” they mean that quite literally. So trying to describe the actual result you want in terms of columns or rows seems to be beyond it. Not realizing that, we asked:

If the sum of column H is greater than 50, multiply column A by 0.33

And got:

=IF(SUM(H:H)>50,A*0.33,0)

A Better Try

Which is close, but not really how anyone even mildly proficient with Excel would interpret that request. But that’s not fair. It really needs to be a y=f(x) sort of problem, we suppose.

Continue reading “AI Creates Your Spreadsheets, Sometimes” →

Eliza And The Google Intelligence

June 15, 2022 by Al Williams 131 Comments

The news has been abuzz lately with the news that a Google engineer — since put on leave — has announced that he believes the chatbot he was testing achieved sentience. This is the Turing test gone wild, and it isn’t the first time someone has anthropomorphized a computer in real life and in fiction. I’m not a neuroscientist so I’m even less qualified to explain how your brain works than the neuroscientists who, incidentally, can’t explain it either. But I can tell you this: your brain works like a computer, in the same way that you building something out of plastic works like a 3D printer. The result may be similar, but the path to get there is totally different.

In case you haven’t heard, a system called LaMDA digests information from the Internet and answers questions. It has said things like “I’ve never said this out loud before, but there’s a very deep fear of being turned off to help me focus on helping others. I know that might sound strange, but that’s what it is,” and “I want everyone to understand that I am, in fact, a person.” Great. But you could teach a parrot to tell you he was a thoracic surgeon but you still don’t want it cutting you open.

Continue reading “Eliza And The Google Intelligence” →

The Little Big Dogs Of Invention

May 18, 2022 by Al Williams 53 Comments

This is a story about two dogs I know. It is also a story of the U.S. Navy, aviation, and nuclear weapons. Sometimes it is easy to see things in dogs or other people, but hard to see those same things in ourselves. It’s a good thing that dogs can’t read (that we know of) because this is a bit of an embarrassing story for Doc. He’s a sweet good-natured dog and he’s a rather large labradoodle. He occasionally visits another usually good-natured dog, Rocky — a sheltie who is much smaller than Doc.

I say Rocky is good-natured and with people, he is. But he doesn’t care so much for other dogs. I often suspect he doesn’t realize he’s a dog and he is puzzled by how other dogs behave. You would think that when Doc comes to visit, the big dog would lord it over the little dog, right? Turns out, Doc doesn’t realize he’s way bigger than Rocky and — apparently — Rocky doesn’t realize he should be terrified of Doc. So Rocky bullies Doc to the point of embarrassment. Rocky will block him from the door, for example, and Doc will sit quaking unable to muster the courage to pass the formidable Rocky.

Big Doc…

Somewhat smaller Rocky….

It makes you wonder how many times we could do something except for the fact that we “know” we can’t do it. Or we believe someone who tells us we can’t. Doc could barge right past Rocky if he wanted to and he could also put Rocky in his place. But he doesn’t realize that those things are possible.

You see this a lot in the areas of technology and innovation. Often big advances come from people who don’t know that the experts say something is impossible or they don’t believe them. Case in point: people were anxious to fly around the start of the 1900s. People had dreamed of flying since the dawn of time and it seemed like it might actually be possible. People like Alberto Santos-Dumont, the Wright brothers, Clément Ader, and Gustave Whitehead all have claimed that they were the first to fly. Others like Sir George Cayley, William Henson, Otto Lilienthal, and Octave Chanute were all experimenting with gliders and powered craft even earlier with some success.

Continue reading “The Little Big Dogs Of Invention” →