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Simplifying Slide Rule Calculations with Trig

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[Bob the Science Guy] remembers how to use a slide rule. Even after all these years, it is pretty easy to remember how to multiply and divide. If you can’t remember, you can usually work it out, as long as you understand how slide rules work. But what about sine, cosine, and quadratics? [Bob’s] been making videos about topics like this, and if you’ve wanted to put your slide rule collection to practical use, you’ll enjoy these videos. You can see one below. The trick to the slide rule is that it is deceptively simple. You are in effect adding logarithms and then taking an antilog. The issue is that you still have to have some intuition about the scale of the answer since 2×3 works out the same as 2×3000 or 200×300. But it is even trickier than that. Adding and subtracting is not easy on the slide rule. [Bob] shows how to use your math skills to convert problems that might have been addition problems into trig problems. So while it might seem mo...

The 10€ Gamepad

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We aren’t sure what [Lazy_Duck] is doing with video games, but it must require a lot of controllers. Dismayed at the cost and complexity of commercial gamepads, they started soldering and 3D printing to get a cheaper basic controller . The emphasis is on throwing things together, so there’s no dedicated PCB. Just a protoboard with an RP2040-Zero, a joystick, a few buttons, and a microswitch. A 3D-printed case rounds out the project. On the printing side, the device uses heat-set threaded inserts, which should make for a very sturdy build. For software, the GP2040-CE firmware handles everything, acting like a controller and managing configuration via a web page. Even if you don’t want a cheap gamepad, you could apply the principles and software used here to create any kind of gamepad you want. The firmware makes good use of the dual-core RP2040. It also offers a lot you could add to your version of the cheap controller, like OLED displays, RGB LEDs, and more. Of c...

Fairbuds 2 Teardown Shows Little Glue, Easy Battery Swap

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In a world where wireless earbuds are increasingly seen as devices that you toss into the e-waste bin as soon as they stop working, it’s heartening to see companies take the opposite approach with their designs. In a recent teardown of the new Fairbuds 2 by [iFixit] we get a blow-by-blow report of disassembling one of these devices, getting to its rechargeable LIR1054 coin cell, as well as the very accessible PCB should you have to replace a shorted capacitor or similar issue. Much like with the first version, the 3.6 V lithium-ion coin cell can be extracted simply by pulling on the battery door, which leverages it out of the enclosure. Despite this easy access method and no glue these earbuds are still IP54 rated, so they’re safe to wear when you’re dashing for shelter in a sudden downpour. To get further into the device, you have to overcome the plastic clips that hold the enclosure together, along with what appears to be a few dabs of glue. Inside it you find th...

Using Optical Waveguide Arrays to Make Sheets Sense Shapes

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Determining the shape of an object which can change dynamically is a bit of a challenge, one that especially vexes those who are really into Virtual Reality. Sensing the orientation of various limbs and appendages usually requires external sensors like cameras, or limit the focus to specific details like just the hands and fingers of the player. A more comprehensive and potentially flexible approach might be possible using optical waveguides, as demonstrated by [Qifan Yu] et al. in a recent article in Advanced Intelligent Systems . Waveguides are structures that guide electromagnetic waves, with optical waveguides such as used here targeting EM radiation in the optical band. This can even allow for the use of cheap and plentiful optical fiber, though here custom elastomeric waveguides are manufactured. These are laid out onto the sheet in a double-sided, overlapping zig-zag pattern, which allows for easy reconstruction of the shape of said sheet based on how the wave propagation thr...

45 Years Later, The Sinclair ULA Design Documents Surface

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In the 8-bit home computer boom of the early 1980s, Sir Clive Sinclair’s machines were always among the cheapest on the market, often packing a surprising level of sophistication in their limited hardware. If there was one component that was key to their success it was the Ferranti ULA, or Uncommitted Logic Array, a clever way to make an ASIC from a chip containing a library of logic parts ready made. The Sinclair ULAs have been reverse engineered, but their full details have remained a mystery. Until now it seems, because here’s [Happy Little Diodes] with a treasure trove of original Ferranti design documents covering all the Sinclair parts. The documents were picked up on eBay, and contain folders with printouts, engineering drawings, and hand written design notes. They cover the full range of Sinclair products of the era, including the ZX81 and Spectrum, the ZX printer , the Microdrive , the Spectrum Interface 1, and even the curious little flat screen TV. Oddly the IP ...

Linux Kernel Drops AI Tag Requirement, Uses Meta AI For Code Reviews

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Since we last covered the way that the Linux Kernel project has been dealing with the influx of code created using LLM-based coding assistants, all the way back in April , things have changed a lot, with most recently the Linux maintainers deciding to fully drop the requirement to mark LLM-assisted commits with the Assisted-by tag. While not a fully uncontroversial decision – as also reported by Phoronix – with key maintainers already having made this decision it seems certain to proceed. This is not the only change made fairly recently, with a ‘Sashiko’ bot introduced that is supposed to handle code reviews. In a July LKML post [Linus Torvalds] defends this decision , with a follow-up post in August by [Jakub Kicinski] it being stated that budget has been secured for using Meta’s LLMs, using said LLM-based resources for reviewing patches, as well as creating and editing commit messages. As noted by [Jakub] they’re running multiple frontier mode...

C64 Hardware Simulator Isn’t (Just) For Playing Around

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If you want to play old Commodore games, there are C-64 emulators available for just about any platform– but most of them are so high level, they’re really meant for just that: playing games. [antirez] has a different goal with his c64-hw-sim project — it’s a lower-level emulation that simulates every chip and every connection on an ASSY 250407 motherboard, and all the chips on it, too. Ever wondered what happens when a specific chip is missing, or a random pin is shorted to ground or forced high? You can do all that in software, with no risk of harming antique hardware. While that might be a fun bit of faffing about for a certain sort electronics sadist, the real utility is to learn about the hardware, both in the abstract and to help you troubleshoot a board you might have. It’s likely that many given failure modes reproduce the same effects– lots of things can knock out the display output, for example–but at least if you’ve reproduced ...