Surplus Syringes Make Satisfactory Tuner For Amateur Radio Experimentation

August 14, 2021 by Ryan Flowers 8 Comments

Amateur Radio as a hobby has a long history of encouraging experimentation using whatever one might have on hand. When [Tom Essenpreis] wanted to use his 14 MHz antenna outside of its designed frequency range, he knew he’d need an impedance matching circuit. The most common type is an L-Match circuit which uses a variable capacitor and a variable inductor to adjust the usable frequency range (resonance) of an antenna. While inefficient in some specific configurations, they excel at bridging the gap between the 50 ohm impedance of the radio and the unknown impedance of an antenna.

No doubt raiding his junk box for parts, [Tom] hacked together a variable capacitor and inductor using ferrite rods from AM radios, hot glue, magnet wire, copper tape, and some surplus 60ml syringes. You can see that he ground out the center of the plunger to make room for ferrite rods. Winding the outside of the syringe with magnet wire, the alignment of the ferrite can be adjusted via the plunger, changing the characteristics of the element to tune the circuit. [Tom] reports that he was able to make an on-air contact using his newly made tuner, and we’re sure he enjoyed putting his improvised equipment to use.

If Amateur Radio isn’t your thing, then maybe we can entice you with this syringe based rocket, syringe actuated 3D printed drill press, or vacuum syringe powered dragster. Have your own hack to share? By all means, submit it to the Tip Line!

Goals And Goalposts

August 14, 2021 by Elliot Williams 14 Comments

In the winter, I hatched a vague plan to learn some of the modern unmanned aerial vehicle tech. Everybody needs an autonomous vehicle, and we’ve got some good flying fields within walking distance, so it seemed like it could work. Being me, that meant buying the cheapest gear that could possibly work, building up the plane by myself, and generally figuring out as much as possible along the way. I learn more by making my own mistakes anyway. Sounds like a good summer project.

Fast-forward to August, and the plane is built, controller installed, and I’ve spent most of the last month trying to make them work well together. (The firmware expects a plane with ailerons, and mine doesn’t have them, but apparently I’d rather tweak PID values than simply add a couple wing servos.) But it’s working well enough that it’s launching, flying autonomous waypoint missions, and coming home without any intervention. So, mission accomplished, right?

Nope. When I’m enjoying a project, I have a way of moving the goalposts on myself. I mean, I don’t really want to be done anyway. When a friend asked me a couple weeks ago what I was planning to do with the plane, I said “take nice aerial videos of that farm over there.” Now I see flight opportunities everywhere, and need to work on my skills. The plane needed an OLED display. It probably still needs Bluetooth for local configuration as well. Maybe a better long-range data link…

This is creeping featurism and moving-the-goalposts in the best of ways. And if this were a project with a deadline, or one that I weren’t simply enjoying, it would be a problem. Instead, having relatively low-key goals, meeting them, and letting them inspire me to set the next ones has been a blast. It makes me think of Donald Papp’s great article on creating hacking “win” projects. There he suggests creating simple goals to keep yourself inspired. I don’t think I could have planned out an “optimal” set of goals to begin with — I’ve learned too much along the way that the next goal isn’t obvious until I know what new capabilities I have. Creeping is the only way.

What about you? Do you plan your hobby projects completely in advance? Not at all? Or do you have some kind of hybrid, moving-the-goalposts sort of strategy?

Reverse Engineering A Topfield VFD Front Panel

August 14, 2021 by Tom Nardi 2 Comments

Hackers love the warm glow of a vacuum fluorescent display (VFD), and there’s no shortage of dead consumer electronics from which they can be pulled to keep our collective parts bins nicely stocked. Unfortunately, figuring out how to actually drive these salvaged modules can be tricky. But thanks to the efforts of [Lauri Pirttiaho], we now have a wealth of information about a VFD-equipped front panel used in several models of Topfield personal video recorders.

The board in question is powered by a Hynix HMS99C52S microcontroller and includes five buttons, a small four character 14-segment display, a larger eight character field, and an array of media-playback related icons. There’s also a real-time clock module onboard, as well as an IR receiver. [Lauri] tells us this same board is used in at least a half-dozen Topfield models, which should make it relatively easy to track one down.

After determining what goes where in the 6-pin connector that links the module with the recorder, a bit of poking with a logic analyzer revealed that they communicate over UART. With the commands decoded, [Lauri] was able to write a simple Python tool that lets you drive the front panel with nothing more exotic than a USB-to-serial adapter. Though keep in mind, you’ll need to provide 17 VDC on the appropriate pin of the connector to fire up the VFD.

What’s that? You don’t need the whole front panel, and just want to pull the VFD itself off the board? Not a problem. Our man [Lauri] was kind enough to document how data is passed from the Hynix microcontroller to the display itself; critical information should you want to liberate the screen from its PVR trappings.

If you manage to get your hands on one of these modules, it would be an ideal addition to a custom media streamer. Though we suppose simply turning it into a network-controlled clock would be a suitable alternative if you’re looking for something a bit easier.

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Pomodachi: A Productivity Pet You Feed By Working

August 14, 2021 by Kristina Panos 1 Comment

Being productive doesn’t have to be a lonely endeavor. Even if you’re a lone wolf, who wouldn’t benefit from having a cute little productivity pet to cheer them on? That’s the idea behind [droxpopuli]’s Pomodachi, which combines a hardware implementation of the Pomodoro technique with a virtual pet. It adds some fun, but doesn’t overly gamify time tracking to the point of distraction. And this is way more fun than just sticking a pair of googly eyes on a tomato-shaped timer.

Inside the box is an Adafruit HalloWing M4 Express and a NeoKey FeatherWing with two Kailh box white switches for a satisfying clack. [droxpopuli] printed up a PyPortal-inspired case and added a glass lens for a spiffy tube TV look.

Pomo himself is a cute little jack-o-lantern looking creature with a teddy bear face and no arms or legs. He could eat with his face, but prefers to be fed. That’s where you come in. You feed him by completing a set of four 20-minute work intervals.

Don’t worry about keeping track of time, because he does that for you and spends the time foraging for food. When it’s break time, Pomo lets you know and suggests an activity. This is when you press the button and feed him. If your productivity begins to flag a bit, don’t freak out — there’s a multiplier for catching up, and you have seven chances before Pomo runs away forever.

The Pomodoro Technique is pretty great for productivity, and it’s versatile, too. Here’s a hydration-based Pomodoro that will flood your desk if you don’t drink enough water.

[via Hackaday.io]

USB Mouse Hack For Pachyderm Protection

August 13, 2021 by Ryan Flowers 25 Comments

When most of us think of seismometers, our minds conjure up images of broken buildings, buckled roads, and search and rescue teams digging through rubble. But when [Subir Bhaduri] his team were challenged with solving real world problems as frugally as possible as part of the 2020 Frugal Science course, he thought of farmers in rural India for whom losing crops due to raiding elephants is a reality. Such raids can and have caused loss of life for humans and elephants alike. How could he apply scientific means to prevent such conflicts, and do it on the cheap?

Whether inspiration came from using a computer mouse with the cursor speed turned up to “orbital velocity” is debatable, but [Subir] set forth to find out if such sensitivity could be leveraged for the seismic detection of the aforementioned elephants. His proof of concept is a fantastically frugal low cost seismograph using an optical mouse and some cheap PVC pipe and fittings.

We invite you to watch the video below the break to find out how it works. You’ll be impressed as we were by [Subir]’s practical application of engineering principles. And keep your eyes open for the beautiful magnetic damper hack. It’s a real treat!

If pontificating pesky pachyderms p-waves piques your interest, perhaps you’ll appreciate previous projects which produce data with piezo pickups and plumbing parts.

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Google’s Periodic Table

August 13, 2021 by Al Williams 43 Comments

One of the nice things about the Internet is that you don’t need huge reference books anymore. You really don’t need big wall charts, either. A case in point: what science classroom didn’t have a periodic table of the elements? Now you can just look up an interactive one from Google. They say it is 3D and we suppose that’s the animations of the Bohr model for each atom. You can debate if it is a good idea to show people Bohr models or not, but it is what most of us learned, after all.

While the website is probably aimed more at students, it is a handy way to look up element properties and it is visually attractive, too. You probably remember, the columns are no accident in a periodic table, so the actual format doesn’t vary from one instance of it to another. However, we liked the col coding and the information panel that appears when you click on an element.

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Filtering Coffee Through 3D Printed Glass

August 13, 2021 by Lewin Day 11 Comments

Typically, when we think of 3D printing, we think of gooey melted plastics or perhaps UV-cured resins. However, there’s a great deal of research going on around printing special impregnated filaments with alternative materials inside. [Ahron Wayne] has been working on these very materials, and decided to make himself a brew with a prototype print.

Tasty, but [Ahron] notes you shouldn’t drink in the lab.

The subject of [Ahron]’s experimentation is a glass-impregnated filament under development by The Virtual Foundry. The filament is full of tiny glass particles, and the idea is that it can be printed like any regular plastic filament. From there, it’s heated in what’s known as a debinding process, which removes the plastic in the print. Then, it’s heated again in a sintering process to bond the remaining glass particles together.

It’s a complex process, and one that leads to some shrinkage in dimensions as well as porosity in the final part. However, where some might see failure, [Ahron] saw opportunity. The porous printed part was used to filter coffee, with the aid of a little vacuum from what sounds like a water venturi.

[Ahron] notes it’s not a particularly efficient way to make coffee but it did work. We’ve seen exciting work with steel-impregnated filaments, too. Video after the break.

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