neodymium

37 Articles

Hall Sensors Offer Drop-In Replacement For Drifting Game Console Joysticks

May 24, 2023 by 42 Comments

No bananas were harmed in the making of this Hall effect drift-proof joystick replacement. OK, not really — two bananas were turned to mush. But it’s OK, they’re just bananas, after all.

Why bananas, you ask? Because [Marius Heier] uses them to demonstrate what we all intuitively know — that rubbing something over and over again tends to wear it away — but engineers seem to have forgotten. Wear such as this, with resistance material rather than fruits, is what causes the dreaded drift, a problem that the world collectively spends $20 billion a year dealing with, according to [Marius].

While numbers like that seem to be firmly in class-action lawsuit territory, sometimes it’s best to take matters into your own hands and not wait for the courts. The fix [Marius] shows here is to yank the potentiometers off a PS4 joystick and replace them with contactless Hall effect sensors. The end of the shaft for each axis gets a diametral neodymium magnet attached to it, while a 3D printed bracket holds a tiny custom PCB in close proximity. The PCB has an AS5600 Hall sensor, which translates the shaft angle to an analog voltage output. After programming the chip over its I2C bus, the sensor outputs a voltage proportional to the angle of each shaft, just like the original pots, but without all the wear and tear.

While [Marius] is selling these as drop-in replacements for PS4 controllers, he plans to release all the design files so you can build one yourself. He also has his sights set on replacements for PS5 and Xbox controllers, so watch for those. This isn’t his first foray into joystick hacking, having shared his 3D Hall effect and haptic feedback joysticks with us previously.

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Exploring The Hall Effect For Haptic Feedback PS4 Joysticks

January 26, 2023 by 10 Comments

Modern gaming console controllers aren’t without their annoyances — Joy-Con drift, anyone? The problems might stem from design deficiencies, but we suspect that user enthusiasm and the mechanical stress it can introduce might play a significant role as well. Either way, [Marius Heier] decided to take a look at what would be required to build a better joystick and came up with some interesting results.

The first video below lays the basic groundwork, with a bunch of experiments with 3-axis Hall effect sensors, specifically the Texas Instruments TMAG5273 and TMAG5170. They’re essentially the same sensor with different interfaces — SPI for the 5170 and I2C for the 5273. Using just one of these sensors, he was able to build a joystick with the usual X- and Y- axis control, but also with a rotary axis. What’s more, he built a motorized version using two NEMA 17 steppers to mechanically drive the stick back to center.

The joystick is bulky, but it looks like he’s got plans for a much smaller one with [Carl Bugeja]-style PCB motors that should fit into a PS4 controller. That’s the subject of the second video below, which uses a different Hall sensor — an Allegro A1304 — and is mainly concerned with getting the output of a non-motorized but considerably miniaturized joystick stick talking the language that the controller expects. It’s not a simple process, but it seems to be coming along nicely, and we’ll be watching progress closely.

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Clever Mechanism Makes A Linear Control From A Rotary Hall Sensor

January 9, 2023 by 81 Comments

Every once in a while we stumble across something so simple yet so clever that we just have to call it out. This custom linear Hall effect sensor is a perfect example of this.

By way of backstory, [Nixieguy], aka [The Electronic Mercenary], offers up a relatable tale — in the market for suitable hardware to make the game Star Citizen more enjoyable, and finding the current commercial joystick offerings somewhat wanting, he decided to roll his own controllers. This resulted in the need for a linear sensor 100 mm in length, the specs for which — absolute sensing, no brushes or encoders, easily sourced parts — precluded most of the available commercial options, like linear pots. What to do?

The solution [Nixieguy] settled on was to use a Hall effect sensor and a diametrally magnetized neodymium ring magnet. The magnet is rotated through 180 degrees by a twisted aluminum bar, which is supported in a frame by bearings. A low-friction slider with a slot captures the bar; moving the slider along the length of the control rotates the bar, which rotates the magnet, which allows the Hall sensor to measure the angle of the magnetic field. Genius!

The parts for the prototype sensor are all made from 0.8-mm aluminum sheet stock and bent to shape. The video below shows the action better than words can describe it, and judging by the oscilloscope trace, the output of the sensor is pretty smooth. There’s clearly a long way to go to tighten things up, but the basic mechanism looks like a clear win to us.

Hats off to [Nixieguy] for this one, which we’ll surely be following for more developments. In the meantime, if you need to brush up on the Hall effect, [Al Williams] did a nice piece on that a while back.

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Fifteen Flat CRTs And A Bunch Of Magnets Make For Interactive Fun

January 6, 2023 by 46 Comments

If you were a curious child growing up when TVs were universally equipped with cathode ray tubes, chances are good that you discovered the effect a magnet can have on a beam of electrons. Watching the picture on the family TV warp and twist like a funhouse mirror was good clean fun, or at least it was right up to the point where you permanently damaged a color CRT by warping the shadow mask with a particularly powerful speaker magnet — ask us how we know.

To bring this experience to a generation who may never have seen a CRT display in their lives, [Niklas Roy] developed “Deflektron”, an interactive display for a science museum in Switzerland. The CRTs that [Niklas] chose for the exhibit were the flat-ish monochrome tubes that were used in video doorbell systems in the late 2000s, like the one [Bitluni] used for his CRT Game Boy. After locating fifteen of these things — probably the biggest hack here — they were stripped out of their cases and mounted into custom modules. The modules were then mounted into a console that looks a little like an 80s synthesizer.

In use, each monitor displays video from a camera mounted to the module. Users then get to use a selection of tethered neodymium magnets to warp and distort their faces on the screen. [Niklas] put a lot of thought into both the interactivity of the exhibit, plus the practical realities of a public installation, which will likely take quite a beating. He’s no stranger to such public displays, of course — you might remember his interactive public fountain, or this cyborg baby in a window.

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Faceless Clock Makes You Think Twice About How It Works

November 18, 2022 by 23 Comments

We love projects that make you do a double-take when you first see them. It’s always fun to think you see one thing, but then slowly realize everything is not quite what you expected. And this faceless analog clock is very much one of those projects.

When we first saw [Shinsaku Hiura]’s “Hollow Clock 4,” we assumed the trick to making it look like the hands were floating in space would rely on the judicious use of clear acrylic. But no, this clock is truly faceless — you could easily stick a finger from front to back. The illusion is achieved by connecting the minute hand to the rim of the clock, and rotating the whole outer circumference through a compact 3D printed gear train. It’s a very clever mechanism, and it’s clear that it took a lot of work to optimize everything so that the whole look of the clock is sleek and modern.

But what about the hour hand? That’s just connected to the end of the minute hand at the center of the clock’s virtual face, so how does that work? As it is with most things that appear to be magical, the answer is magnets. The outer rim of the clock actually has another ring, this one containing a pair of neodymium magnets. They attract another magnet located in the very end of the hour hand, dragging it along as the hour ring rotates. The video below shows off the secrets, and it gives you some idea of how much work went into this clock.

We’re used to seeing unique and fun timepieces and other gadgets from [Shinsaku Hiura] — this up-flipping clock comes to mind, as does this custom RPN calculator — but this project is clearly a step beyond.

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Magnetic Gearbox Design Improvements Are Toothless But Still Cool

October 8, 2022 by 9 Comments

Any project that contains something called a “flux modulator” instantly commands our attention. And while we’re pretty sure that [Retsetman] didn’t invent it after hitting his head on the toilet, this magnetic gearbox is still really cool.

Where most gearboxes have, you know, gears, a magnetic gearbox works by coupling input and output shafts not with meshing teeth but via magnetic attraction. [Retsetman]’s version has three circular elements nested together on a common axis, and while not exactly a planetary gear in the traditional sense, he still uses planetary terminology to explain how it works. The inner sun gear is a rotor with four pairs of bar magnets on its outer circumference. An outer ring gear has ten pairs of magnets, making the ratio of “teeth” between the two gears 10:2. Between these two elements is the aforementioned flux modulator, roughly equivalent to the planet gears of a traditional gearbox, with twelve grub screws around its circumference. The screws serve to conduct magnetic flux between the magnets, dragging the rotating elements along for the ride.

This gearbox appears to be a refinement on [Retsetman]’s earlier design, and while he provides no build files that we can find, it shouldn’t be too hard to roll your own designs for the printed parts.

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Iron Nitrides: Powerful Magnets Without The Rare Earth Elements

September 1, 2022 by 36 Comments

Since their relatively recent appearance on the commercial scene, rare-earth magnets have made quite a splash in the public imagination. The amount of magnetic energy packed into these tiny, shiny objects has led to technological leaps that weren’t possible before they came along, like the vibration motors in cell phones, or the tiny speakers in earbuds and hearing aids. And that’s not to mention the motors in electric vehicles and the generators in wind turbines, along with countless medical, military, and scientific uses.

These advances come at a cost, though, as the rare earth elements needed to make them are getting harder to come by. It’s not that rare earth elements like neodymium are all that rare geologically; rather, deposits are unevenly distributed, making it easy for the metals to become pawns in a neverending geopolitical chess game. What’s more, extracting them from their ores is a tricky business in an era of increased sensitivity to environmental considerations.

Luckily, there’s more than one way to make a magnet, and it may soon be possible to build permanent magnets as strong as neodymium magnets, but without any rare earth metals. In fact, the only thing needed to make them is iron and nitrogen, plus an understanding of crystal structure and some engineering ingenuity.

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