You Can 3D Print A 12,500 RPM Brushless Motor

June 28, 2023 by 18 Comments

Typically, when most of us need a motor, we jump online to order one from a catalogue. [Levi Janssen] recently had to build his own for a college project, however, and learned a lot along the way.

[Levi] whipped up his brushless DC motor design in OnShape. The motor has six coils in the stator, with the rotor carrying eight neodymium magnets. It’s an axial flux design, with the rotor’s magnets sitting above the coils. This makes construction very easy using 3D printed components. Axial flux motors also have benefits when it comes to power density and cooling, though optimization is outside the scope of [Levi]’s work here.

[Levi]’s video covers both the development of the motor itself as well as the drive circuit, too. The latter is of key value if you’re interested in the vagaries of driving these motors, which is far more complex than running a simple brushed motor. He even gets his motor up to 12,500 rpm with his homebrewed drive circuit.

Making your own motors can help you solve some difficult engineering challenges, like building motorized rollerblades. Alternatively, if winding coils sounds too slow and too hard, you can just use off-the-shelf gear and hack it to make it work. Here, we support both methods.

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Democratizing Space, One Picosatellite At A Time

June 28, 2023 by 50 Comments

There was a time when putting an object into low Earth orbit was the absolute pinnacle of human achievement. It was such an outrageously expensive and complex undertaking that only a world superpower was capable of it, and even then, success wasn’t guaranteed. As the unforgiving physics involved are a constant, and the number of entities that could build space-capable vehicles remained low, this situation remained largely the same for the remainder of the 20th century.

Nathaniel Evry

But over the last couple of decades, the needle has finally started to move. Of course spaceflight is still just as unforgiving today as it was when Sputnik first streaked through the sky in 1957, but the vast technical improvements that have been made since then means space is increasingly becoming a public resource.

Thanks to increased commercial competition, putting a payload into orbit now costs a fraction of what it did even ten years ago, while at the same time, the general miniaturization of electronic components has dramatically changed what can be accomplished in even a meager amount of mass. The end result are launches that don’t just carry one or two large satellites into orbit, but dozens of small ones simultaneously.

To find out more about this brave new world of space exploration, we invited Nathaniel Evry, Chief Research Officer at Quub, to host last week’s DIY Picosatellites Hack Chat.

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Field Testing A Home Made WiFi Antenna

June 28, 2023 by 29 Comments

Most readers will be aware that a good way to extend WiFi range is to use a better antenna for those 2.4 GHz signals, but at the same time such high frequency hijinks have something of a reputation of being not for the faint-hearted. [Dereksgc] puts that reputation to the test by building a helical WiFi antenna — and if that weren’t enough — he also subjects it to a field test. In a real field, is there any other way?

We’ve put both videos below the break, and you can find his helical antenna calculator on his website and the parametric CAD file for the scaffold in his GitHub repository. He first delivers a crash course in the fundamentals of helical antennas before diving into the construction, and even soldering on an impedance matching strip. The field testing involves setting up a base station with an FTP server on a phone, and connecting to it with a variety of antennas over increasing distance across farmland. We’ve characterised antennas in this way before, and it really does give an immediate view of their performance.

In this case the helix comfortably outperforms a commercial patch antenna and a laptop’s internal antenna, making such an antenna a very worthwhile piece of work whether you’re making a fixed link or indulging in a bit of casual wardriving.

The tools mentioned here will make helical antennas a snap, but this isn’t the first time we’ve touched on the subject.

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Earth’s Final Frontier: Exploring The Alien Depths Of The Earth’s Oceans

June 28, 2023 by 29 Comments

Despite how hostile to life some parts of the Earth’s continents are, humanity has enthusiastically endeavored over the course of millennia to establish at least a toehold on each of them. Yet humanity has barely ventured beyond the surface of the oceans which cover around three-quarters of the planet, with human activity in these bodies of water dropping off quickly along with the fading of light from the surface.

Effectively, this means for all intents and purposes we have to this day not explored the vast majority of the Earth’s surface, due to over 70% of it being covered by water. As an ocean planet, much of Earth’s surface is covered by watery depths of multiple kilometers, with each 10 meters of water increasing the pressure by one atmosphere (1.013 bar), so that at a depth of one kilometer we’re talking about an intense 101 atmospheres.

Over the past decades, the 1985 discovery of Titanic’s wreck approximately 3.8 kilometer below the surface of the Atlantic, the two year long search for AF447’s black boxes, and the fruitless search for the wreckage of MH370 despite washed-up remnants have served as stark reminders of just how alien and how hostile the depths of the Earth’s oceans are. Yet with both tourism and mining efforts booming, will we one day conquer the full surface of Earth?

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Custom Keyboard Built For Diablo 3 Action

June 28, 2023 by 3 Comments

Custom mechanical keyboards are a great way to show off your passion and skill for electronics and design. They’re also perfect when you need to optimize your setup for a certain game or piece of software. [Pakequis] did just that with his Bad Thing of the Edge mechanical keyboard build.

[Pakequis] occasionally plays Diablo 3 on a tiny 7-inch laptop, which as you might expect, doesn’t have a keyboard conducive to gaming. Thus, he designed a mechanical keyboard with a series of important actions mapped to keys for the left hand. Naturally, that was an opportunity to have fun with the keycaps, which all feature graphics for their relevant in-game functions. The prototype was built with surplus keys from an old PTZ camera controller, but the final version runs Cherry MX switches. There are also a set of RGB LEDs with a variety of fun effects. The whole thing is run by a Raspberry Pi Pico, which is perfectly suited for building custom USB HID devices.

Hackers build custom keyboards for all kinds of reasons, like ergonomics, style, or just sheer absurdist fun.

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An ESP In Your Mini TV

June 28, 2023 by 14 Comments

When miniature LCD TVs arrived on the market they were an object of desire, far from the reach of tech-obsessed youngsters. Now in the age of smartphones they’re a historical curiosity, but with the onward march of technology you can have one for not a lot. [Taylor Galbraith] shows us how, with an ESP32 and an LCD we rather like because of its CRT-like rounded corners.

What he’s created is essentially a small media player, but perhaps what makes it of further interest is its migration from a mess of wires on a breadboard to a rather nice PCB. He’s not released the board files at the time of writing, but since the software can all be found in the GitHub repository linked above, we live in hope. On it are not only the ESP and the screen, but also a battery management board, an audio amplifier, and a small speaker. For now it’s a bare board, but we hope he’ll complete it with a neatly designed case for either a pocket player or a retro-styled mini TV. Until then you can see his progress in the videos below the break.

If you’re after more ESP32 media player inspiration, this isn’t the first retro-themed media player we’ve brought you.

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Build A Tesla Coil With Just Three Components

June 27, 2023 by 3 Comments

Tesla coils are beautiful examples of high voltage hardware, throwing sparks and teaching us about all kinds of fancy phenomena. They can also be quite intimidating to build. [William Fraser], however, has come up with a design using just three components.

It’s a simplified version of the “Slayer Exciter” design, which nominally features a transistor, resistor and LED, along with a coil, and runs on batteries. [William] learned that adding a capacitor in parallel with the batteries greatly improved performance, and allowed the removal of the LED without detriment. [William] also learned that the resistor was not necessary either, beyond starting the coil oscillating.

The actual 3-component build uses a 10 farad supercapacitor as a power source, hooked up to a 2N3904 NPN transistor and an 85-turn coil. It won’t start oscillating on its own, but when triggered by a pulse of energy from a piezo igniter, it jerks into life. The optimized design actually uses the shape of the assembled component leads to act as the primary coil. The tiny Tesla coil isn’t big and bold enough to throw big sparks, but it will light a fluorescent tube at close proximity.

If you like your Tesla coils musical, we have those too.

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