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.

Cursing The Curse Of Cursive

September 27, 2022 by Kristina Panos 114 Comments

Unlike probably most people, I enjoy the act of writing by hand — but I’ve always disliked signing my name. Why is that? I think it’s because signatures are supposed to be in cursive, or else they don’t count. At least, that’s what I was taught growing up. (And I’m really not that old, I swear!)

Having the exact same name as my mother meant that it was important to adolescent me to be different, and that included making sure our signatures looked nothing alike. Whereas her gentle, looping hand spoke to her sensitive and friendly nature, my heavy-handed block print was just another way of letting out my teen angst. Sometime in the last couple of decades, my signature became K-squiggle P-squiggle, which is really just a sped-up, screw-you version of my modern handwriting, which is a combination of print and cursive.

D’Nealian print. Notice the ‘monkey tails’ on every possible lowercase letter.

D’Nealian cursive. Notice the stroke order and the ridiculous capital Q.

But let’s back up a bit. I started learning to write in kindergarten, but that of course was in script, with separate letters. Me and my fellow Xennial zeigeistians learned a specific printing method called D’Nealian, which was designed to ease the transition from printing to cursive with its curly tails on every letter.

We practiced our D’Nealian (So fancy! So grown-up!) on something called Zaner-Bloser paper, which is still used today, and by probably second grade were making that transition from easy Zorro-like lowercase Zs to the quite mature-looking double-squiggle of the cursive version. It was as though our handwriting was moving from day to night, changing and moving as fast as we were. You’d think we would have appreciated learning a way of writing that was more like us — a blur of activity, everything connected, an oddly-modular alphabet that was supposed to serve us well in adulthood. But we didn’t. We hated it. And you probably did, too.

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Honor Your Hacker Heroes

September 24, 2022 by Elliot Williams 3 Comments

We recently ran an article on a sweet percussion device made by minimal-hardware-synth-madman [Gijs Gieskes]. Basically, it amplifies up an analog meter movement and plays it by slamming it into the end stops. Rhythmically, and in stereo. It’s got that lovely thud, plus the ringing of the springs. It takes what is normally a sign that something’s horribly wrong and makes a soundtrack out of it. I love it.

[Gijs] has been making electro-mechanical musical hacks for about as long as I’ve been reading Hackaday, if not longer. We’ve written up no fewer than 22 of his projects, and the first one on record is from 2005: an LSDJ-based hardware sequencer. All of his projects are simple, but each one has a tremendously clever idea at its core that comes from a deep appreciation of everything going on around us. Have you noticed that VU meters make a particular twang when they hit the walls? Sure you have. Have you built a percussion instrument out of it? [Gijs] has!

Maybe it’s a small realization, and it’s not going to change the world by itself, but I’ve rebuilt more than a couple projects from [Gijs]’ repertoire, and each one has made my life more fun. And if you’re a regular Hackaday reader, you’ve probably seen hundreds or thousands of similar little awesome ideas played out, and maybe even taken some of them on as your own as well. When they accumulate up, I believe they can change the world, at least in the sense of filling up a geek’s life. I hope that feeling comes across when we write up a project. Those of you out there hacking, we salute you!

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.

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Floppy Disk Sings: I’m Big In Japan

September 13, 2022 by Al Williams 67 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.

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Who Is Responsible For Your Safety?

September 10, 2022 by Elliot Williams 182 Comments

We recently posted a video where some ingenious metal-shop hackers made a simple jig to create zig-zag oil grooves on the inside of a cylinder, and the comment section went wild. What ensued was a flood of complaints that the video displayed unsafe shop practices, from lack of safety glasses to wearing flip-flops while operating a lathe.

Where the comments went off the rails were people asking Hackaday to remove our discussion of the video, because the commenters thought that we were somehow implicitly encouraging open-toed footwear in the presence of machine tools. We certainly weren’t! We wanted you all to see the clever machining hack, and be inspired to build your own. We figure that you’ve got the safety angle covered.

Now don’t get me wrong – there were safety choices made in the video that I would not personally make. But it also wasn’t my shop and I wasn’t operating the machines. And you know who is ultimately responsible for the safety in my basement shop? Me! And guess who is responsible for safety in your shop.

But of course, none of us know everything about every possible hazard. (Heck, I wrote just that a few weeks ago!) So while we’re sympathetic with the “that’s not safe!” crew, we’re not going to censor inspiring hacks just because something done along the way wasn’t done in the way we would do it. Instead, it’s our job, in the comment section as in Real Life™, to help each other out and share our good safety tips when we can.

You’ll see some crazy stuff in videos, and none of it is to be repeated without thinking. And if you do see something dodgy, by all means point it out, and mention how you would do it better. Turn the negative example around for good, rather than calling for its removal. Use the opportunity to help, rather than hide.

But also remember that when the chips are flying toward your personal eyeballs, it’s up to you to have glasses on. We all do potentially hazardous things all the time, and it’s best to be thinking about the risks and their mitigation. So stay safe out there. Keep on learning and keep on hacking!