A Simple But Effective Receiving Loop Antenna

August 25, 2024 by Jenny List 21 Comments

There’s a joke in the world of radio that all you need for a HF antenna is a piece of wet string, but the truth is that rudimentary antennas rarely perform well. Random pieces of wire may pull in some signal, but along with it comes a ton of unwanted interference and noise. It’s thus worth putting in the effort to make a better antenna, and if you’re not fortunate enough to have a lot of space, your best choice may be a magnetic loop. [Robert Hart] takes us through the design of a receive-only coaxial loop. It’s referred to as a Moebius loop because the conductor takes a “twist” path between the inner and outer halfway around.

The idea of a loop antenna is simple enough. It’s an inductor intended to respond to the magnetic portion of the wave rather than the electric part. They’re normally made of a single turn of wire in a loop of diameter well below half a wavelength, and, in their transmitting versions, they are often tuned to resonance by an air-spaced variable capacitor. Coaxial loops like this one provide enhanced resistance to electrical noise. He’s using some rather expensive Andrews coax for its rigidity, but the less well-heeled can use cheaper stuff without penalty. The result, when put on a frame of PVC pipe and a speaker stand, is an excellent portable receiving antenna, and if we’re being honest, something we might also consider in our own shack.

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PCB data sheet of a custom 4-bit microcontroller

Building A Microcontroller From Scratch: The B4 Thinker Project

August 25, 2024 by Heidi Ulrich No comments

[Marius Taciuc’s] latest endeavor, the B4 Thinker, offers a captivating glimpse into microcontroller architecture through a modular approach. This proof-of-concept project is meticulously documented, with a detailed, step-by-step guide to each component and its function.

Launched in 2014, the B4 Thinker project began with the ambitious goal of building a microcontroller from scratch. The resulting design features a modular CPU architecture, including a base motherboard that can be expanded with various functional modules, such as an 8-LED port card. This setup enables practical experimentation, such as writing simple assembly programs to control dynamic light patterns. Each instruction within this system requires four clock pulses to execute, and the modular design allows for ongoing development and troubleshooting.

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Hackaday Links: August 25, 2024

August 25, 2024 by Dan Maloney 8 Comments

The Sun has been remarkably active lately, so much so that it might have set a new sunspot record. According to the sun watchers at the Space Weather Prediction Center, on August 8, the Solar Dynamics Observatory snapped a picture that was positively bedazzled with sunspots. Counting methods vary, but one count put the sunspot number at a whopping 337 that day. That would be the largest number since 2001, during the peak of Solar Cycle 23. The sunspot number is highly correlated with solar storms and coronal mass ejections; more spots mean more magnetic activity and more chance for something to go very, very wrong. We’ve been pretty lucky so far with Solar Cycle 25; despite being much more active than the relatively lazy Cycle 24 and much stronger than predicted, most of this cycle’s outbursts have been directed away from Earth or only dealt us a glancing blow. Seeing all those spots, though, makes us think it’s only a matter of time before we get hit with something that does more than make pretty lights.

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3D Printed Electronics Breadboard

August 25, 2024 by Maya Posch 9 Comments

The printed breadboard cover, seen from the bottom. (Credit: CHEP, YouTube) — The printed breadboard cover as seen from the bottom. (Credit: CHEP, YouTube)

Does it make sense to make your own breadboards rather than purchasing off the shelf ones? As [Chuck Hellebuyck] notes in a recent video on DIY, 3D-printed breadboards, there’s a certain charm to making a breadboard exactly the size you need, which is hard to argue with. The inspiration came after seeing the metal breadboard spring clips on sale by [Kevin Santo Cappuccio], who also has a 3D printable breadboard shell project that they fit into. This means that you can take the CAD model (STEP file) and modify it to fit your specifications before printing it, which is what [Chuck] attempts in the video.

The models were exported from TinkerCAD to Bambu Lab Studio for printing on a Bambu Lab A1 Mini FDM printer. After a failed first print (which the A1 Mini, to its credit, did detect), a model was printed on a Creality K1 Max instead. Ultimately [Chuck] traced this back to the Bambu Lab Studio slicer failing to add the inner grid to the first layer, which the Creality slicer did add, caused by the ‘wall generator’ setting in the Bambu Lab slicer being set to ‘Classic’ rather than ‘Arachne,’ which can vary line width.

After this, the models printed fine and easily fit onto the spring clips that [Chuck] had soldered down on some prototyping board. A nice feature of these spring clips is that they have a bit of space underneath them where an SMD LED can fit, enabling functional (or just fancy) lighting effects when using a custom PCB underneath the contraption. As for whether it’s worth it depends on your needs. As [Chuck] demonstrates, it can be pretty convenient for a small breadboard on an add-on card (with or without custom lighting) like this, but it’s unlikely to replace generic breadboards for quick prototyping. We can, however, imagine a custom breadboard with mounting points for things like binding posts, switches, or potentiometers.

If we had that kind of custom breadboard, we wouldn’t need these. People were making custom breadboards back in 1974, but they didn’t look like these.

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A Simple 6DOF Hall Effect ‘Space’ Mouse

August 25, 2024 by Dave Rowntree 14 Comments

The 3DConnexion Space mouse is an interesting device but heavily patent-protected, of course. This seems to just egg people on to reproduce it using other technologies than the optical pickup system the original device uses. [John Crombie] had a crack at building one using linear Hall effect sensors and magnets as the detection mechanism to good — well — effect.

Using the SS49E linear Hall effect sensor in pairs on four sides of a square, the setup proves quite straightforward. Above the fixed sensor plate is a moveable magnet plate centred by a set of springs. The magnets are aligned equidistant between each sensor pair such that each sensor will report an equal mid-range signal with zero mechanical displacement. With some simple maths, inputs due to displacements in-plane (i.e., left-right or up-down) can be resolved by looking at how pairs compare to each other. Rotations around the vertical axis are also determined in this manner.

Tilting inputs or vertical movements are resolved by looking at the absolute values of groups or all sensors. You can read more about this by looking at the project’s GitHub page, which also shows how the to assemble the device, with all the CAD sources for those who want to modify it. There’s also a detour to using 3D-printed flexures instead of springs, although that has yet to prove functional.

On the electronics and interfacing side of things, [John] utilises the Arduino pro micro for its copious analog inputs and USB functionality. A nice feature of this board is that it’s based on the ATMega32U4, which can quickly implement USB client devices, such as game controllers, keyboards, and mice. The USB controller has been tweaked by adjusting the USB PID and VID values to identify it as a SpaceMouse Pro Wireless operating in cabled mode. This tricks the 3DConnexion drivers, allowing all the integrations into CAD tools to work out of the box.

We do like Space Mouse projects. Here’s a fun one from last year, an interesting one using PCB coils and flexures, and a simple hack to interface an old serial-connected unit.

V-Slot Wheels Or Linear Rails?

August 25, 2024 by Al Williams 45 Comments

In the early days of 3D printers, most builds used smooth rods and bearings that rode on them. But these days, printers are shipping with either V-slot extrusions with Delrin wheels or linear rails. Which is best? Everyone seems to have an opinion, but [Spencer] decided to compare them using some well-defined experiments, and he shares his results in the video below.

Common wisdom is that linear rails create a better print quality, but [Spencer] didn’t really find that much difference. He does admit, however, that he isn’t an expert on setting up linear rails, so perhaps there’s something he could have done better. He did note that the rails were quieter but that, for both cases, the noise generated by the moving rails was only a small fraction of the total noise generated by the printer. The rails were also more stable in terms of resonance. Input shaping can help overcome that, though, so it probably isn’t that important in a modern printer.

What do you think? Are linear rail upgrades worth it? Let us know in the comments. We’ve been 3D printing long enough that we are hard-pressed to complain much about any of the prints we produce today on printers that cost a fraction of what we spent on our first ones.

Of course, you could go with string. Putting rails together with or without slots is its own art form.

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A 3D-printed talking milk jug with a speech bubble that says 'glug'.

Talking Milk Jug Says Glug-Glug-Glug

August 25, 2024 by Kristina Panos 7 Comments

Children can be a great source of daily inspiration, especially when they are just beginning to speak in full sentences and starting to let their little personalities show.

[Franklinstein] has the cutest toddler, and she loves her toy espresso machine, especially the little milk carton that came with it. Well, one day, Daddy made a glug-glug sound that delighted her, and he was inspired to build an entirely new milk jug that would make that special sound whenever it was turned over.

In order to keep the build relatively simple, [Franklinstein] used a sound module with an SD card and a tilt switch to activate it. There’s not much else to the build, really — just the usual suspects like a boost converter, a charging module, and a speaker, of course. In case you couldn’t tell, the enclosure and the internal skid that the electronics assemble onto are 3D printed.

This is really cute, and [Franklinstein]’s daughter seems to love it. Everything is available, including some nice instructions if you want to make one of your own. Be sure to check out the neat build video after the break.

The things we do for kids. Seriously.

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