Remotely Controlled Vehicles Over Starlink

January 8, 2025 by 35 Comments

Modern remote control (RC) radios are capable of incredible range, but they’re still only made for line-of-sight use. What if you want to control a vehicle that’s 100s of kilometers away, or even on the other side of the planet? Cellular is an option, but is obviously limited by available infrastructure — good luck getting a cell signal in the middle of the ocean.

But what if you could beam your commands down from space? That’s what [Thingify] was looking to test when they put together an experimental RC boat using a Starlink Mini for communications. Physically, there was no question it would work on the boat. After all, it was small, light, and power-efficient enough. But would the network connection be up to the task of controlling the vehicle in real-time?

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Making Sure Your Patch Cables Are Ready For RF Work

January 8, 2025 by 3 Comments

How do you know that your patch cables are good? For simple jumper wires, a multimeter is about all you need to know for sure. But things can get weird in the RF world, in which case you might want to keep these coaxial patch cable testing tips in mind.

Of course, no matter how high the frequency, the basics still apply, and [FesZ] points out in the video below that you can still get a lot of mileage out of the Mark 1 eyeball and a simple DMM. Visual inspection of the cable and terminations can reveal a lot, as can continuity measurements on both the inner and outer conductors. Checking for shorts between conductors is important, too. But just because the cable reads good at DC doesn’t mean that problems aren’t still lurking. That’s when [FesZ] recommends breaking out a vector network analyzer like the NanoVNA. This tool will allow you to measure the cable’s attenuation and return loss parameters across the frequency range over which the cable will be used.

For stubborn problems, or just for funsies, there’s also time-domain reflectometry, which can be done with a pulse generator and an oscilloscope to characterize impedance discontinuities in the cable. We’ve covered simple TDR measurement techniques before, but [FesZ] showed a neat trick called time-domain transformation, which uses VNA data to visualize the impedance profile of the whole cable assembly, including its terminations.

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Toot-B-Gone, With The FartMaster 3000

January 7, 2025 by 19 Comments

Face it, we’ve all been there, in a crowded workshop building something, and horror of horrors, things are going to get a little… windy. Do you try to drop it quietly and hope nobody says the rhyme, do you bolt for the door, or can you tough it out and hold it in? Never fear, because [Roman_2798881] has got your back, with the FartMaster 3000.

No doubt born of urgent necessity, it’s a discreet wall-mounted fixture for a shop vac line which allows a casual activation of the shopvac as if some sawdust needed removing, and backing up for a safe disposal of any noxious clouds under cover of the vacuum’s whirring.

We have to admit, this one gave us something of a chuckle when we saw it in the Printables feed, but on closer inspection it’s a real device that by our observation could have been useful in more than one hackerspace of our acquaintance. There’s a square funnel in front of a piece of ducting, with a rotary valve to divert the vacuum in an appropriate direction to conceal the evidence.

Then simply turn it back to straight through, vac your pretend sawdust, and nobody’s the wiser. Unless of course, you also integrated a fart-o-meter.

Regular (Expression) Chess

January 7, 2025 by 17 Comments

[Nicholas Carlini] found some extra time on his hands over the holiday, so he decide to do something with “entirely no purpose.” The result: 84,688 regular expressions that can play chess using a 2-ply minmax strategy. No kidding. We think we can do some heavy-duty regular expressions, but this is a whole other level.

As you might expect, the code to play is extremely simple as it just runs the board through series of regular expressions that implement the game logic. Of course, that doesn’t count the thousands of strings containing the regular expressions.

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Polarizer clock with rainbow glow clockface

Bending Light, Bending Time: A DIY Polarizer Clock

January 7, 2025 by 7 Comments

Imagine a clock where the colors aren’t from LEDs but a physics phenomenon – polarization. That’s just what [Mosivers], a physicist and electronics enthusiast, has done with the Polarizer Clock. It’s not a perfect build, but the concept is intriguing: using polarized light and stress-induced birefringence to generate colors without resorting to RGB LEDs.

The clock uses white LEDs to edge-illuminate a polycarbonate plate. This light passes through two polarizers—one fixed, one rotating—creating constantly shifting colours. Sounds fancy, but the process involves more trial and error than you’d think. [Mosivers] initially wanted to use polarizer-cut numbers but found the contrast was too weak. He experimented with materials like Tesa tape and cellophane, choosing polycarbonate for its stress birefringence.

The final design relies on a mix of materials, including book wrapping foil and 3D printed parts, to make things work. It has its quirks, but it’s certainly clever. For instance, the light dims towards the center, and the second polarizer is delicate and finicky to attach.

This gadget is a splendid blend of art and science, and you can see it in the video below the break. If you’re inspired, you might want to look up polariscope projects, or other birefringence hacks on Hackaday.

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Gaze Upon This Omni-directional Treadmill’s Clever LEGO Construction

January 7, 2025 by 16 Comments

Want to see some wildly skillful LEGO construction? Check out [Banana Gear Studios]’ omni-directional treadmill which showcases not only how such a thing works, but demonstrates some pretty impressive problem solving in the process. Construction was far from straightforward!

A 9×9 grid of LEGO shafts all turning in unison is just one of the non-trivial design challenges.

In principle the treadmill works by placing an object on a bed of identical, rotating discs. By tilting the discs, one controls which edge is in contact with the object, which in turn controls the direction the object moves. While the concept is straightforward, the implementation is a wee bit more complex. LEGO pieces offer a rich variety of mechanical functions, but even so, making a 9×9 array of discs all rotate in unison turns out to be a nontrivial problem to solve. Gears alone are not the answer, because the shafts in such a dense array are a bit too close for LEGO gears to play nicely.

The solution? Break it down into 3×3 self-contained chunks, and build out vertically with gimbals to take up the slack for gearing. Use small elastic bands to transfer power between neighbors, then copy and paste the modular 3×3 design a few times to create the full 9×9 grid. After that it’s just a matter of providing a means of tilting the discs — which has its own challenges — and the build is complete.

Check out the video below to see the whole process, which is very nicely narrated and illustrates the design challenges beautifully. You may see some similarities to Disney’s own 360° treadmill, but as [Banana Gear Studios] points out, it is a technically different implementation and therefore not covered by Disney’s patent. In an ideal world no one would worry about getting sued by Disney over an educational LEGO project posted on YouTube, but perhaps one can’t be too careful.

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The Helicone: Toy Or Mathematical Oddity?

January 7, 2025 by 7 Comments

We always enjoy videos from the [Mathologer], but we especially liked the recent video on the Helicone, a toy with a surprising connection to mathematics. The toy is cool all by itself, but the video shows how a sufficiently large heliocone models many “natural numbers” and acts, as [Mathologer] puts it, acts as “microscope to probe the nature of numbers.”

The chief number of interest is the so-called golden ratio. A virtual model of the toy allows easy experimentation and even some things that aren’t easily possible in the real world. The virtual helicone also allows you to make a crazy number of layers, which can show certain mathematical ideas that would be hard to do in a 3D print or a wooden toy.

Apparently, the helicone was [John Edmark’s] sculpture inspired by DNA spirals, so it is no surprise it closely models nature. You can 3D print a real one.

Of course, the constant π makes an appearance. Like fractals, you can dive into the math or just enjoy the pretty patterns. We won’t judge either way.

We’ve seen math sequences in clocks that remind us of [Piet Mondrian]. In fact, we’ve seen more than one of those.

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