Autopsy Of A Drifting Thumbstick Reveals All

April 12, 2023 by Lewin Day 34 Comments

Analog sticks have become a core part of modern video game controllers. They also routinely fail or end up drifting, consigning expensive controllers to the garbage. [sjm4306] recently did a repair job on an Oculus VR gaming controller with drifting analog sticks, and decided to do an autopsy to figure out what actually went wrong.

A microscope reveals gouges in the resistive material, caused by the metal contacts inside the analog stick. This happened via regular use.

The video starts by taking apart the analog joystick itself by prying off the metal case. Inside, we get a look at the many tiny individual components that make up a modern thumbstick. Of most interest, though, are the components that make up the potentiometers within the stick. Investigation revealed that the metal contacts that move with the stick had worn through the resistive coating on the thin plastic membrane in the base of the joystick, creating the frustrating drift problem.

It doesn’t have to be this way. Analog sticks in modern controllers could be manufactured with higher-quality components that don’t wear so easily. After all, it’s hard to imagine a 90s video game controller wearing out as fast as this modern Oculus unit. But everything is built to a price, at the end of the day, and that’s just how it goes. Video after the break.

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There’s Cash In Them Old Solar Panels

April 12, 2023 by Bryan Cockfield 82 Comments

The first solar panels may have rolled out of Bell Labs in the 1950s, with major press around their inconsistent and patchy adoption in the decades that followed, but despite the fanfare they were not been able to compete on a price per kilowatt compared to other methods of power generation until much more recently. Since then the amount of solar farms has increased exponentially, and while generating energy from the sun is much cleaner than most other methods of energy production and contributes no greenhouse gasses in the process there are some concerns with disposal of solar panels as they reach the end of their 30-year lifespan. Some companies are planning on making money on recycling these old modules rather than letting them be landfilled. Continue reading “There’s Cash In Them Old Solar Panels” →

The Eyes Have It With This Solid State Magic Eye

April 12, 2023 by Dan Maloney 7 Comments

The classic “Magic Eye” tuning indicator was a fantastic piece of vacuum tube technology that graced all kinds of electronic gear for a fair fraction of the 20th century. But despite its prevalence, finding a new-old-stock Magic Eye tube is a tall order these days, especially for the rare versions like the 6T5. No worries, though, since direct plug-in solid-state replacements for the 6T5 are now a thing, thanks to [Gord Rabjohn]. Continue reading “The Eyes Have It With This Solid State Magic Eye” →

Weird 555 Function Generator Uses Feedback

April 12, 2023 by Lewin Day 20 Comments

There are plenty of designs out there for sawtooth and triangle function generators, many of them using the humble 555 IC. Few are readily voltage controlled, making them difficult to work with using a DAC, though. Enter this useful design posted to EDN!

The nifty design allows both waveshape and amplitude to be controlled via voltage. You could hook up a couple of potentiometers and call it done. Or, even better, you can control these parameters via PWM output from a microcontroller. Handy, no? It’s achieved by a fancy routing that sends feedback from the 555’s output pin to the CV input, instead of the usual design that uses the THR and TRG pins instead. The design also allows the production of both symmetrical and asymmetrical triangle waveforms, and as a bonus, the whole oscillator draws less than 4 mW of power.

If you’re looking for a nifty triangle/sawtooth generator that sits neatly in your otherwise-digital design, this could be for you. Or, you might like to explore the sheer mountain of other 555 hacks we’ve featured over the years. We even held a contest! If you’ve got new 555 hacks the world needs to see, don’t hesitate to drop them into the tipsline.

Disabling Intel’s Backdoors On Modern Laptops

April 12, 2023 by Bryan Cockfield 32 Comments

Despite some companies making strides with ARM, for the most part, the desktop and laptop space is still dominated by x86 machines. For all their advantages, they have a glaring flaw for anyone concerned with privacy or security in the form of a hardware backdoor that can access virtually any part of the computer even with the power off. AMD calls their system the Platform Security Processor (PSP) and Intel’s is known as the Intel Management Engine (IME).

To fully disable these co-processors a computer from before 2008 is required, but if you need more modern hardware than that which still respects your privacy and security concerns you’ll need to either buy an ARM device, or disable the IME like NovaCustom has managed to do with their NS51 series laptop.

NovaCustom specializes in building custom laptops with customizations for various components and specifications to fit their needs, including options for the CPU, GPU, RAM, storage, keyboard layout, and other considerations. They favor Coreboot as a bootloader which already goes a long way to eliminating proprietary closed-source software at a fundamental level, but not all Coreboot machines have the IME completely disabled. There are two ways to do this, the HECI method which is better than nothing but not fully trusted, and the HAP bit, which completely disables the IME. NovaCustom is using the HAP bit approach to disable the IME, meaning that although it’s not completely eliminated from the computer, it is turned off in a way that’s at least good enough for computers that the NSA uses.

There are a lot of new computer manufacturers building conscientious hardware nowadays, but (with the notable exception of System76) the IME and PSP seem to be largely ignored by most computing companies we’d otherwise expect to care about an option like this. It’s certainly still an area of concern considering how much power the IME and PSP are given over their host computers, and we have seen even mainline manufacturers sometimes offer systems with the IME disabled. The only other options to solve this problem are based around specific motherboards for 8th and 9th generation Intel desktops, or you can go way back to hardware from 2008 and install libreboot to eliminate, rather than disable, the IME.

Thanks to [Maik] for the tip!

Tech In Plain Sight: Field Guide To Power Plugs

April 12, 2023 by Al Williams 70 Comments

It is the bane of worldwide travel: there isn’t just one way to get AC power from the wall. The exact connector — and what you can expect when you plug in — differs from country to country. Even if you stay home, you must account for this if your designs go places and expect to plug into the wall. If you’ve ever looked at a universal adapter, it is full of prongs and pins like a metallic porcupine. Where do all those pins go?

Of course, there are some easy ways to sidestep the whole issue if you don’t need AC power. Much low-power gear now just provides a USB or barrel connector. Then you can use an area-appropriate adapter or charger to power your device. Batteries work, too. But if you need to plug in, you will run into other kinds of plugs.

Switching power supplies have helped. In the old days, many things expected either 125V or 250V and didn’t work with the opposite voltage. Switching power supplies often allow a wide input range or have a switch to select one range or the other. These two voltages will cover almost any situation. If you have something that must have one voltage or the other, you’ll need a transformer — also called a converter — to step the voltage up or down. But most often, these days, you just need an adapter. There are slight variations. For example, some countries supply 100V or 110V, but that usually doesn’t make much difference. You also need to understand if your equipment cares if the AC is 50 Hz or 60 Hz.

Most of the power sockets you’ll find around the world will fall into one of several categories. The categories range from A to N. Even among these, however, there are variations.

Type A

For example, the common type A plug and socket are what Americans call “two prong.” If you live in the US, you’ve probably noticed that the plug is polarized. That is, one pin is slightly wider than the other so the plug can only go in one way. The wide pin is connected to the circuit neutral. The maximum load for this connector is 15A. It is difficult to find type A sockets anymore, other than on cheap extension cords or things like lamps that pass through their electrical connections to a second socket. Type B is far more common and type A plug will fit in a type B socket.

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Dual Extrusion Support Without PVA

April 12, 2023 by Al Williams 5 Comments

If you have an FDM printer that features multiple hotends or can otherwise switch between different filaments, you’ve surely thought about using the capability to lay down dedicated support material. Historically the filament of choice for this is PVA, since it can be dissolved in water once the print has finished. But if you’ve ever used it, you’ll know it’s not without its own challenges. Luckily, there may be an alternative — [ModBot] had heard that it is possible to use PLA to support PETG and vice-versa so he decided to try it. You can see how it works in the video below.

Of course, you can simply use PLA to support PLA and PETG to support PETG. Depending on the supports and slicer settings, though, it can be hard to remove the support after printing cleanly. Slicers have made major improvements in this area, but it still isn’t ideal. Some use HIPS for support, but that requires a solvent to dissolve and is also a bit exotic compared to PLA and PETG.

To illustrate, [ModBot] printed some test articles with the alternate support and did more reference prints using the same material with different parameters. The typical gap slicers use is 0.2 mm, but when using the different materials you can set the gap to zero. For the reference parts he set the gap to zero and 0.1 mm, both closer than you would normally print.

The PLA-only prints were essentially impossible to separate. While the PETG prints separated with tools, the resulting surfaces were ugly, with support residue and scarring. But the prints with two materials and zero gap pulled apart readily with no tools and left a beautiful surface underneath.

If you have the ability to do dual extrusion, this could be a great trick to have in your toolbox. Granted, PVA will still be of interest if you have support buried deep inside some structure where it is physically difficult to get to. Water can go where tweezers can’t. But for supporting large accessible areas, this looks like a game-changer.

Sometimes automatic supports can use a little help. There are plenty of supports and best practices for supports if you want to fine-tune your process.

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