Month: January 2021

3D Printed Pi Arcade Is An Emulation Horn Of Plenty

January 20, 2021 by 19 Comments

Let’s be honest, building a home arcade cabinet isn’t exactly the challenge it once was. There’s plenty of kits out there that do all the hard work for you, and they even sell some pretty passable turn-key units at Walmart now. If you want to put a traditional arcade cabinet in your home, it’s not hard to get one.

Which is why this wild build by [Rafael Rubio] is so interesting. The entirely 3D printed enclosure looks like some kind of art piece from the 1970s, and is a perfect example of the kind of unconventional designs made possible by low-cost additive manufacturing. Building something like this out of wood or metal would be nightmare, especially for the novice; but with even a relatively meager desktop 3D printer you’re only a few clicks away from running off your own copy.

Removable side panels allow access to the electronics.

Inside the nautilus-like enclosure is a Raspberry Pi running Retropie, a 10″ LCD panel from Pimoroni, and a GeeekPi interface board that connects up to the 8-way joystick and arcade buttons. [Rafael] has included a Bill of Materials and an assembly overview that you can follow along with, though the cavernous internal dimensions of the enclosure certainly give you ample of room for improvisation if you’d rather blaze your own path.

Like the retro-futuristic computer terminals created by [Oriol Ferrer Mesià], this arcade machine completely reinvents a traditional design that most people take for granted. Is this layout actually better than the standard arcade cabinet? It’s not really our place to say. But it’s certainly a new and unconventional approach to “solved” problem, and that’s what we’re all about.

A One-Transistor Ham Transmitter Anyone Can Build

January 20, 2021 by 65 Comments

What attracts a lot of people to amateur radio is that it gives you the ability to make your own gear. Scratch-building hams usually start by making their own antennas, but eventually, the itch to build one’s own radio must be scratched. And building this one-transistor transmitter is just about the simplest way to dive into the world of DIY radio.

Of course, limiting yourself to eight components in total entails making some sacrifices, and [Kostas (SV3ORA)]’s transmitter is clearly a study in compromise. For starters, it’s only a transmitter, so you’ll need to make other arrangements to have a meaningful conversation. You’ll also have to learn Morse code because the minimalist build only supports continuous-wave (CW) mode, although it can be modified for amplitude modulation (AM) voice work.

The circuit is flexible enough that almost any part can be substituted and the transmitter will still work. Most of the parts are junk-bin items, although the main transformer is something you’ll have to wind by hand. As described, the transformer not only provides feedback to the transistor oscillator, but also has a winding that powers an incandescent pilot lamp, and provides taps for attaching antennas of different impedances — no external tuner needed. [SV3ORA] provides detailed transformer-winding instructions and shows the final build, which looks very professional and tidy. The video below shows the rig in action with a separate receiver providing sidetone; there’s also the option of using one of the WebSDR receivers sprinkled around the globe to verify you’re getting out.

This little transmitter looks like a ton of fun to build, and we may just try it for our $50 Ham series if we can find all the parts. Honestly, the hardest to come by might be the variable capacitor, but there are ways around that too.

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Oscilloscope Learns How To Speak Japanese, And VGA

January 20, 2021 by 7 Comments

Nostalgia aside, there are a few things an analog scope can still do better than a digital, with oscilloscope art being a prime example. The blue-green glow of phosphors in a real CRT just add something special to such builds, and as a practitioner of this craft, [Aaron] decided to paint a New Year’s affirmation on his oscilloscope screen, in Japanese calligraphy of all things.

When used in X-Y mode, analog oscilloscopes lend themselves nicely to vector-based graphics, which is the approach [Aaron] has taken with previous “Oscilloclock” builds, like the Metropolis Clock. The current work, however, doesn’t use vector graphics, opting instead to turn the scope into the business end of a VGA display. He had previously developed the hardware needed to convert a VGA signal into X- and Y-axis analog outputs, so the bulk of the work was rendering the calligraphy, first in ink and then scanning and processing the results into a file. In keeping with the Japanese theme, [Aaron] chose a rare scope from Nihon Tsushinki Co., Ltd., from 1963. It’s a beautiful piece of equipment and obviously lovingly restored, and with the VGA adapter temporarily connected, the four Japanese characters scroll gracefully up the screen, delivering the uplifting message: “Steady progress, day by day.”

[Aaron] sure puts a lot of work into his analog scope builds, which we’ve featured a few times. Check out the clock he made from Grandpa’s old Heathkit scope, or his Tektronic vectorscope clock. And don’t forget about other forms of oscilloscope art — they can make music too, after all.

Multi-Channel Battery Monitor Aces First Sea Trial

January 20, 2021 by 4 Comments

A little over a a year ago, we covered an impressive battery monitor that [Timo Birnschein] was designing for his boat. With dedicated batteries for starting the engines, cranking over the generator, and providing power to lights and other amenities, the device had to keep tabs on several banks of cells to make sure no onboard systems were dipping into the danger zone. While it was still a work in progress, it seemed things were progressing along quickly.

But we know how it is. Sometimes a project unexpectedly goes from having your full attention to winning an all-expense-paid trip to the back burner. In this case, [Timo] only recently put the necessary finishing touches on his monitor and got it installed on the boat. Recent log entries on the project’s Hackaday.io page detail some of the changes made since the last time we checked in, and describe the successful first test of the system on the water.

Certainly the biggest issue that was preventing [Timo] from actually using the monitor previously was the lack of an enclosure and mounting system for it. He’s now addressed those points with his 3D printer, and in the write-up provides a few tips on shipboard ergonomics when it comes to mounting a display you’ll need to see from different angles.

The printed enclosure also allowed for the addition of some niceties like an integrated 7805 voltage regulator to provide a solid 5 V to the electronics, as well as a loud piezo beeper that will alert him to problems even when he can’t see the screen.

Under the hood he’s also made some notable software improvements. With the help of a newer and faster TFT display library, he’s created a more modern user interface complete with a color coded rolling graph to show voltages changes over time. There’s still a good chunk of screen real estate available, so he’s currently brainstorming other visualizations or functions to implement. The software isn’t using the onboard NRF24 radio yet, though with code space quickly running out on the Arduino Nano, there’s some concern about getting it implemented.

As we said the first time we covered this project, you don’t need to have a boat to learn a little something from the work [Timo] has put into his monitoring system. Whether you’re tracking battery voltages or temperatures reported by your BLE thermometers, a centralized dashboard that can collect and visualize that data is a handy thing to have.

Automated Balcony Shade Uses NFC

January 20, 2021 by 3 Comments

[Udi] lives in an apartment with a pleasant balcony. He also has three kids who are home most of the time now, so he finds himself spending a little more time out on the balcony than he used to. To upgrade his experience, he installed a completely custom shade controller to automatically open and close his sunshade as the day progresses.

Automatic motors for blinds and other shades are available for purchase, but [Udi]’s shade is too big for any of these small motors to work. Finding a large servo with a 2:1 gear ration was the first step, as well as creating a custom mount for it to attach to the sunshade. Once the mechanical situation was solved, he programmed an ESP32 to control the servo. The ESP32 originally had control buttons wired to it, but [Udi] eventually transitioned to NFC for limit switch capabilities and also implemented voice control for the build as well.

While not the first shade controller we’ve ever seen, this build does make excellent use of appropriate hardware and its built-in features and although we suppose it’s possible this could have been done with a 555 timer, the project came together very well, especially for [Ubi]’s first Arduino-compatible build. If you decide to replicate this build, though, make sure that your shade controller is rental-friendly if it needs to be.

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The Origin Of Cut, Copy, And Paste

January 20, 2021 by 90 Comments

I’m always fascinated that someone designed just about everything you use, no matter how trivial it is. The keyboard you type on, the light switch you turn on, even the faucet handle. They don’t just spontaneously grow on trees, so some human being had to build it and probably had at least a hazy design in mind when they started it.

Some things are so ubiquitous that it is hard to remember that someone had to dream them up to begin with. A friend of mine asked me the other day why we use Control+X and Control+V to manipulate the clipboard almost universally. Control+C for copy makes sense, of course, but it is still odd that it is virtually universal in an industry where everyone likes to reinvent the wheel. I wasn’t sure of the answer but figured it had to do with some of the user interface standards from IBM or Sun. Turns out, it is much older than that.

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DIY HEPA Fan Clears The Stale Office Air

January 20, 2021 by 26 Comments

Although it would be nice, we can’t all work from home. If you have to spend the day in close quarters with other people, you might want more protection than just a mask and sanitizer. Check out [jshanna]’s DIY HEPA filtering fan — it looks like a breeze to build and uses commonly-available parts plus a few 3D-printed pieces to put it all together.

The basis of this attractive and useful office must-have is a muffin fan from Amazon that has an optional variable speed controller. A long threaded rod runs up the center of the HEPA filter, so it attaches kind of like a lampshade. The fan draws up air from underneath and blows it upward through the filter and out into the room. Whenever the HEPA filter gets dirty, just take it out and wash it.

Are you still buying disposable masks? You might save money in the long run by making your own.