Author: Dan Maloney

3368 Articles

Impatience Is A Virtue When Testing This Old Maritime Teleprinter

July 16, 2022 by 1 Comment

[Larry Wall], inventor of Perl, once famously said that programmers have three key virtues: sloth, hubris, and impatience. It’s safe to say that these personality quirks are also present in some measure in most hardware hackers, too, with impatience being perhaps the prime driver of great hacks. Life’s too short to wait for someone else to build it, whatever it may be.

Impatience certainly came into play for [Sebastian (AI5GW)] while hacking a NAVTEX receiver (in German). The NAVTEX system allows ships at sea to receive text broadcast alerts for things like changes in the weather or hazards to navigation. The trouble is, each NAVTEX station only transmits once every four hours, making tests of the teleprinter impractical. So [Sebastian]’s solution was to essentially create his own NAVTEX transmitter.

Job one was to understand the NAVTEX protocol, which is a 100-baud, FSK-modulated signal with characters encoded in CCIR 476. Since this encoding is also used in amateur radio teletype operations, [Sebastian] figured there would surely be an Arduino library for encoding and decoding it. Surprisingly, there wasn’t, but there is now, allowing an Arduino to produce the correct sequence of pulses for a CCIR 476-encoded message. Fed into a function generator, the mini-NAVTEX station’s signal was easily received and recorded by the painfully slow teleprinter. There’s that impatience again.

We thought this was a neat hack, and we especially appreciate that [Sebastian]’s efforts resulted in a library that could be useful to hams and other radio enthusiasts in the future. We’ve talked about some more modern amateur radio digital modes, like WSPR and FT8, but maybe it’s time to look at some other modes, too.

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Collaborative Effort Gets Laser Galvos Talking G-Code

July 15, 2022 by 9 Comments

Everyone should know by now that we love to follow up on projects when they make progress. It’s great to be able to celebrate accomplishments and see how a project has changed over time. But it’s especially great to highlight a project that not only progresses, but also gives back a little to the community.

That’s what we’re seeing with [Les Wright]’s continuing work with a second-hand laser engraver. It was only a few weeks ago that we featured his initial experiments with the eBay find, a powerful CO2 laser originally used for industrial marking applications. It originally looked like [Les] was going to have to settle for a nice teardown and harvesting a few parts, but the eleven-year-old tube and the marking head’s galvanometers actually turned out to be working just fine.

The current work, which is also featured in the video below, mainly concerns those galvos, specifically getting them working with G-code to turn the unit into a bit of an ad hoc laser engraver. Luckily, he stumbled upon the OPAL Open Galvo project on GitHub, which can turn G-code into the XY2-100 protocol used by his laser. While [Les] has nothing but praise for the software side of OPAL, he saw a hardware hole he could fill, and contributed his design for a PCB that hosts the Teensy the code runs on as well as the buffer and line driver needed to run the galvos and laser. The video shows the whole thing in use with simple designs on wood and acrylic, as well as interesting results on glass.

Of course, these were only tests — we’re sure [Les] would address the obvious safety concerns in a more complete engraver. But for now, we’ll just applaud the collaboration shown here and wait for more updates.

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Bringing Some Discipline To An SDR Transmitter

July 13, 2022 by 16 Comments

The proliferation of software-defined radio (SDR) technology has been a godsend for RF hobbyists. SDR-based receivers and transmitters have gotten so cheap that you’ve probably got a stick or two lying around your bench right now — we can see three from where we sit, in fact.

But cheap comes at a price, usually in the form of frequency stability, which can be prohibitive in some applications — especially amateur radio, where spectrum hygiene is of the utmost concern. So we were pleased to see [Tech Minds] tackle the SDR frequency stability problem by using a GPS-disciplined oscillator. The setup uses an ADALM-PLUTO SDR transceiver and a precision oscillator from Leo Bodnar Electronics. The oscillator can be programmed to output a rock-solid, GPS-disciplined signal over a wide range of frequencies. The Pluto has an external oscillator input that looks for 40 MHz, which is well within the range of the GPSDO.

Setup is as easy as plugging the oscillator’s output into the SDR’s external clock input using an SMA to UFL jumper, and tweaking the settings in the SDR and oscillator. Not all SDRs will have an external clock input, of course, so your mileage may vary. But if your gear is suitably equipped, this looks like a great way to get bang-on frequency — the video below shows just how much the undisciplined SDR can drift.

Like any good ham, [Tech Minds] is doing his bit to keep his signals clean and on target. His chief use case for this setup will be to work QO-100, amateur radio’s first geosynchronous satellite repeater. We’ve got to say that we hams living on the two-thirds of the globe not covered by this satellite are just dying to get a geosynchronous bird (or two) of our own to play with like this.

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A Handy Tester For A Mountain Of PS/2 Keybords

July 12, 2022 by 16 Comments

The hacking life is not without its challenges, and chief among these is the tendency to always be in acquisition mode. When we come across a great deal on bulk equipment, or see a chance to rescue some obscure gear from the e-waste stream, we generally pounce on it, regardless of the advisability.

We imagine this is why [Nathan] ended up with a hoard of PS/2 keyboards. Seriously, there are like thousands of the things. And rather than lug a computer to them for testing, [Nathan] put together this handy Arduino-based portable tester to see which keyboards still have some life left in them. The video below goes into detail on the build, but the basics are pretty simple — an Arduino, a 16×2 LCD display, and a few bits and bobs to run it off a LiPo pack and charge it up. Plus, of course, a PS/2 jack to plug in a keyboard and power it up. Interestingly, the 16×2 display is an old Parallax unit, from the days when RadioShack still existed and sold their stuff. That required a little effort to get it working with the Arduino, but in the end it works like a charm — plug in a keyboard and whatever you type shows up on the screen.

Of course, it’s hard to look at something like this, and that mountain of keyboards in the background, and not scheme up ways to really automate the whole test process. Perhaps an old 3D printer with a stylus mounted where the hot end would go could press each key in turn while the tester output is recorded — something like this Wordle-bot, but on a keyboard scale. That kind of goes against [Nathan]’s portability goal, but it’s still fun to think about.

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The Digital Ham Hack Chat

July 11, 2022 by 2 Comments

Join us on Wednesday, July 13 at noon Pacific for The Digital Ham Hack Chat with Rosy Schechter and John Hays!

For most of its existence, amateur radio has been the quintessence of the analog arts. From the very earliest days of radio, hobbyists have been piecing together circuits to ply the radio spectrum, using whatever bits of RF wizardry they managed to pick up — or invent — along the way. From the architecture of the radios to the nature of the conversations they had over the airwaves, ham radio was very much an analog experience.

But if hams are anything, they’re resourceful, and they’ve got a long history of leveraging whatever the current state of the art happens to be. And so when electrical engineering began to dive into the digital world, so too did the hams. Radioteletype, facsimile, and other text-and-data modes lead to things like packet radio, which in turn gave us powerful tools like APRS, FT8, and PACTOR, upon which the current rich infrastructure of location reporting, weak signal digital contacts and beacons, and email service independent of an Internet connection have been built. There’s even a complete TCP/IP network using amateur radio as the physical layer, which even predates the widespread public Internet by many years.

Amateur radio always has been at the forefront of digital communications, but it takes work to keep hams in their leadership position in the field. To help with that, Amateur Radio Digital Communications (ARDC) was established. ARDC is a non-profit dedicated to supporting amateur radio and digital communication science and technology, chiefly through their programs of grants that are available to fund the development of technically innovative open and non-profit projects in amateur radio.

join-hack-chatFor this Hack Chat, ARDC Executive Director Rosy Schechter (KJ7RYV) and Staff Lead John Hays (K7VE) will be joining us to discuss the world of digital communications on the ham bands. Here’s your chance to share your experiences with digital modes, find out about what’s new in digital comms, and find out how to participate in the ARDC grant program and possibly fund the next big thing for the digital ham.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 13 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Hackaday Links: July 10, 2022

July 10, 2022 by 9 Comments

We always like to call out a commercial success stemming from projects that got their start on Hackaday.io, and so we’re proud to announce the release of MAKE: Calculus by Joan Horvath and Rich Cameron, a book that takes a decidedly different approach to teaching calculus than traditional courses. Geared to makers and hackers, who generally tend to have a visual style of learning, the book makes heavy use of 3D-printed models to illustrate the relationships between functions. The project started five years ago as a 2017 Hackaday Prize entry, and resulted in a talk at the 2019 Supercon. Their book is now available for preorder, and might be a great way to reacquaint themselves with calc, or perhaps even to learn it for the first time. Continue reading “Hackaday Links: July 10, 2022” →

Sneeze Into Your Hand, Not Your Elbow With This Nose-Shaped Sanitizer Dispenser

July 9, 2022 by 7 Comments

You’ve got to love a language like German, where not only is it possible for a word or two to stand in for a complex concept, but you don’t even need to speak the language to make a good guess at what it all means. Of course when your project is a giant nose that mock-sneezes sanitizer into your hands, it doesn’t really matter that you call it Der niesende Desinfektionsmittelspender. Humor based on bodily functions is, after all, the universal language.

Working knowledge of German or not, figuring out exactly what [Nina] is doing here isn’t too difficult. Judging by the video below and the build log, the idea is to detect the presence of a hand underneath the dispenser with a simple IR reflective sensor hooked to some kind of microcontroller — an ESP32 in this case. Audio clips of sneezes are stored on an SD card and played back through a small speaker, while a hobby servo pushes the button on an atomizer. It seems as if selecting the proper dispenser was the hardest thing about the project; [Nina] finally settled on a battery-operated mister that was just the right size to fit into the nose. Oh, didn’t we mention the giant, pink, 3D-printed nose that houses the whole thing? Sorry about that — it’s quite subtle and easy to miss.

Anyway, the whole project is a lot of fun and brought a genuine laugh when we saw it. It’s a clever way to poke gentle fun at the germaphobes who came up with other, less whimsical methods of dispensing hand sanitizer. But let’s face it, they ended up being proven pretty much on the mark about things.

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