Misc Hacks

4058 Articles

Wire Loop And Amplifier Solve Audio Problem For The Hearing Impaired

January 29, 2020 by 21 Comments

Imagine being asked to provide sound reinforcement for a meeting that occurs in a large room, where anyone can be the speaker, and in a situation where microphones would hinder the flow of the meeting. Throw in a couple of attendees who have hearing disabilities, and you’ve got quite a challenge to make sure everyone gets heard.

Such a situation faced [David Schneider] at his Quaker meetinghouse, which he ended up solving with this home-brew audio induction loop system. The worship style of conservative sects of the Religious Society of Friends, as the Quakers are formally known, is “silent worship”, where congregants sit together in silence until someone feels moved to share something. Anyone can speak at any time from anywhere in the room, leading to the audio problem.

Rooms mics and a low power FM transmitter didn’t work because those using radio as aids to hearing the service felt awkward, so [David] decided to take advantage of a feature in the hearing aids worn by some members: telecoils. These are inductive receivers built into some hearing aids to send sound directly to them using magnetic fields generated by a loop in the listening area. [David]’s loop ended up being 240 meters of 20-gauge copper wire in the attic above the meeting room. The impedance ended up close to 8 ohms, perfect for feeding directly from the speaker terminals of an old stereo amplifier. Pumping 160 Watts into the coil allows the hearing-aid wearers below hear the service now.

There’s still work to be done on the input side to improve audio quality, but [David]’s solution is elegant in that it helps those who need it most using technology they already have. And perhaps those who need but don’t yet have hearing aids can roll their own.

Mr. Carlson Gets Zapped By Snow

January 25, 2020 by 47 Comments

As a Canadian, [Mr. Carlson] knows a thing or two about extreme winter weather. Chances are good, though, that he never thought he’d get zapped with high voltage generated by falling snow.

[Mr. Carlson]’s shocking tale began with a quiet evening in his jam-packed lab as a snowstorm raged outside. He heard a rhythmic clicking coming from the speakers of his computer, even with the power off. Other speakers in the lab were getting into the act, as was an old radio receiver he had on the bench. The radio, which was connected to an outdoor antenna by a piece of coax, was arcing from a coil to the chassis in the front end of the radio. The voltage was enough to create arcs a couple of millimeters long and bright blue-white, with enough current to give [Mr. Carlson] a good bite when he touched the coax. The discharges were also sufficient to destroy an LED light bulb in a lamp that was powered off but whose power cord was unlucky enough to cross the antenna feedline.

Strangely, the coil from which the arc sprang formed a 36-ohm shunt to the radio’s chassis, giving the current an apparently easy path to ground. But it somehow found a way around that, and still managed to do no damage to the sturdy old radio in the process. [Mr. Carlson] doesn’t offer much speculation as to the cause of the phenomenon, but the triboelectric effect seems a likely suspect. Whatever it is, he has set a trap for it, to capture better footage and take measurements should it happen again. And since it’s the Great White North, chances are good we’ll see a follow-up sometime soon.

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The Truth Is In There: The Art Of Electronics, The X-Chapters

January 23, 2020 by 41 Comments

If you’ve been into electronics for any length of time, you’ve almost certainly run across the practical bible in the field, The Art of Electronics, commonly abbreviated AoE. Any fan of the book will certainly want to consider obtaining the latest release, The Art of Electronics: The x-Chapters, which follows the previous third edition of AoE from 2015. This new book features expanded coverage of topics from the previous editions, plus discussions of some interesting but rarely traveled areas of electrical engineering.

For those unfamiliar with it, AoE, first published in 1980, is an unusually useful hybrid of textbook and engineer’s reference, blending just enough theory with liberal doses of practical experience. With its lively tone and informal style, the book has enabled people from many backgrounds to design and implement electronic circuits.

After the initial book, the second edition (AoE2) was published in 1989, and the third (AoE3) in 2015, each one renewing and expanding coverage to keep up with the rapid pace of the field. I started with the second edition and it was very well worn when I purchased a copy of the third, an upgrade I would recommend to anyone still on the fence. While the second and third books looked a lot like the first, this new one is a bit different. It’s at the same time an expanded discussion of many of the topics covered in AoE3 and a self-contained reference manual on a variety of topics in electrical engineering.

I pre-ordered this book the same day I learned it was to be published, and it finally arrived this week. So, having had the book in hand — almost continuously — for a few days, I think I’ve got a decent idea of what it’s all about. Stick around for my take on the latest in this very interesting series of books.

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A Ploopy Pick And Place

January 23, 2020 by 11 Comments

A fair number of hackers reach that awkward age in their careers – too old for manual pick and place, but too young for a full-fledged PnP machine. The obvious solution is to build your own PnP, which can be as simple as putting a suction cup on the Z-axis of an old 3D-printer. Feeding parts into the pick and place, though, can be a thorny problem.

Or not, if you think your way through it like [Phil Lam] did and build these semi-automated SMD tape feeders. Built for 8-mm plastic or paper tapes, the feeders are 3D-printed assemblies that fit into a rack that’s just inside the work envelope of a pick and place machine. Each feeder has a slot in the top for the tape, which is advanced by using the Z-axis of the PnP to depress a lever on the front of the case. A long tongue in the tape slot gradually peels back the tape’s cover to expose a part, which is then picked up by the PnP suction cup. Any machine should work; [Phil] uses his with a LitePlacer. We like the idea that parts stay protected until they’re needed; the satisfyingly clicky lever action is pretty cool too. See it briefly in action in the video below.

It looks like [Phil] built this in support of his popular Ploopy trackball, which is available both as a kit and fully assembled. We think the feeder design is great whether you’re using PnP or not, although here’s a simpler cassette design for purely manual SMD work.

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Scorigami Bot Charts NFL History In The Making

January 22, 2020 by 6 Comments

NFL Football is a curious game to those who live beyond the borders of the continental United States. Its rules are many and complex, and its scoring system is built on arcane magic. This system means that there are many possible final game scores that have never actually happened in practice. For fans keen to hear of any first-time scores as they happen, Scorigami bot is here to help.

Charting and researching these is the practice of Scorigami, an idea first posited by Jon Bois, and is explored in this SB Nation video. It covers the many impossible scores in NFL, such as 1-0 and 1-1, as well as the possible-but-extremely-unlikely, like 6-1. To keep track of the state of Scorigami means following every score of every NFL game as its played. The ‘bot makes this easier; scraping the NFL livescores page with some nifty Javascript, it tracks each game live for potential first-time scores; the most recent as of writing being the Chiefs beating the Texans 51-31. Not only that, but the ‘bot estimates the most likely possible scorigami scores of games in progress, keeping fans on tenterhooks until the final whistle is blown. Or is it a siren in NFL? Inquiring minds need to know.

Code is naturally available on Github if you want to independently audit the Twitter feed; obviously the sanctity of scorigami results is absolutely paramount, and ensuring as such is a community responsibility. We’ve seen other live-score projects before, like this glowing Super Bowl football.

Paper Glows Up With This Origami Wall Piece

January 22, 2020 by 3 Comments

[Charlyn] recently found herself dissatisfied with the blank expanse of her bedroom walls. Deciding to take matters into her own hands, she set out to build this exquisite origami wall sculpture.

The piece was inspired by a work originally created by [Coco Sato], which she saw on Design Sponge. Materials were sourced, and [Charlyn] began the arduous process of cutting and folding the many, many pieces of paper that would make up the final piece. There were some missteps along the way, which served as a lesson to test early and test often, but a cup of tea and perseverance got the job done.

With the paper components completed, she looked to the electronics. Ten Neopixel LEDs were hooked up to a Particle Photon, giving the project easy IoT functionality. Thanks to IFTTT, the display can be controlled via Google Home, either glowing to create a relaxing vibe, or shutting off when it’s time to sleep. There’s also a smattering of flowers decorating the piece, somewhat of a [Charlyn] trademark.

The LEDs shine from behind the paper structure, creating a subtle, attractive glow. We’re big fans of the combination of LEDs with origami, and hope to see more projects using the material as an effective diffuser. You can even experiment with conductive materials to take things further. Video after the break.

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P-51 Cockpit Recreated With Help Of Local Makerspace

January 22, 2020 by 22 Comments

It’s surprisingly easy to misjudge tips that come into the Hackaday tip line. After filtering out the omnipresent spam, a quick scan of tip titles will often form a quick impression that turns out to be completely wrong. Such was the case with a recent tip that seemed from the subject line to be a flight simulator cockpit. The mental picture I had was of a model cockpit hooked to Flight Simulator or some other off-the-shelf flying game, many of which we’ve seen over the years.

I couldn’t have been more wrong about the project that Grant Hobbs undertook. His cockpit simulator turned out to be so much more than what I thought, and after trading a few emails with him to get all the details, I felt like I had to share the series of hacks that led to the short video below and the story about how he somehow managed to build the set despite having no previous experience with the usual tools of the trade.

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