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Try a PWMPot

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[Stephen Woodward] is familiar with digital potentiometers but is also familiar with their limitations. That spurred him to create the PWMPot which performs a similar function, but with better features than a traditional digital pot. Of course, he admits that this design has some limitations of its own, so — as usual — you have to make your design choices according to what’s important to you. Perhaps the biggest limitation is that the PWMPot isn’t useful at even moderately high frequencies. The circuit works by driving two CMOS switches into an RC circuit. The switches’ inverted phase tends to cancel out any ripple in the signal. The RC circuit is selected to trade response time with the precision of the final voltage output. The CMOS switches used are part of a 74HC4053B IC. While it might not solve all your digital potentiometer problems, there are cases where it will be just what you need. We’ve looked at traditional digital pots before . If you prefer the hard way, grab a reg...
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38C3: It’s TOSLINK, Over Long Distance Fibre

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If you’ve owned a CD player or other piece of consumer digital audio gear manufactured since the 1980s, the chances are it has a TOSLINK port on the back. This is a fairly simple interface that sends I 2 S digital audio data down a short length of optical fibre, and it’s designed to run between something like a CD player and an external DAC. It’s ancient technology in optical fibre terms, with a lowish data rate and plastic fibre, but consider for a minute whether it could be adapted for modern ultra-high-speed conenctions. It’s what [ Ben Cartwright-Cox] has done , and he delivered a talk about it at the recent 38C3 event in Germany. if you’ve cast you eye over any fibre networking equipment recently, you’ll be familiar with SFP ports. These are a standard for plug-in fibre terminators, and they can be had in a wide variety of configurations for different speeds, topographies, and wavelengths. They’re often surprisingly simple inside, so he wondered if he could use them to carry TOS...
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FLOSS Weekly Episode 815: You Win Some, You Lose Some

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This week, Jonathan Bennett and Randal chat with Matija Å uklje about Open Source and the Law! How do Open Source projects handle liability, what should a Contributor License Agreement (CLA) look like, and where can an individual or project turn for legal help? https://matija.suklje.name/ https://openchainproject.org https://matija.suklje.name/fiduciary-license-agreement-20 Did you know you can watch the live recording of the show Right on our YouTube Channel ? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us! Take a look at the schedule here . Direct Download in DRM-free MP3. If you’d rather read along, here’s the transcript for this week’s episode . Places to follow the FLOSS Weekly Podcast: Spotify RSS Theme music: “Newer Wave” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License from Blog – Hackaday https://ift.tt/2hzgn5c
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Running AI Locally Without Spending All Day on Setup

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There are many AI models out there that you can play with from companies like OpenAI, Google, and a host of others. But when you use them, you get the experience they want, and you run it on their computer. There are a variety of reasons you might not like this. You may not want your data or ideas sent through someone else’s computer. Maybe you want to tune and tweak in ways they aren’t going to let you. There are many more or less open models, but setting up to run them can be quite a chore and — unless you are very patient — require a substantial-sized video card to use as a vector processor. There’s very little help for the last problem. You can farm out processing, but then you might as well use a hosted chatbot. But there are some very easy ways to load and run many AI models on Windows, Linux, or a Mac. One of the easiest we’ve found is Msty . The program is free for personal use and claims to be private, although if you are really paranoid, you’ll want to verify that yourself....
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Bending Light, Bending Time: A DIY Polarizer Clock

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

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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...
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The Helicone: Toy or Mathematical Oddity?

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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 Ļ€ makes an appearance. Like fractals, you can dive into the math or just enjoy the pretty patterns. We ...
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