Isolated Oscilloscope Design Process Shows How It’s Done

November 18, 2021 by 31 Comments

[Bart Schroder] was busy designing high voltage variable speed motor drives and was lamenting the inability of a standard scope to visualise the waveforms around the switch transistors. This is due to the three phase nature of such motors being driven with three current waveforms, out of phase with each other by 120 degrees, where current flows between each pair of winding taps, without being referenced to a common notion of ground. The average scope on your bench however, definitely is ground-referenced, so visualising such waveforms is a bit of a faff. Then there’s the fact that the motors run at many hundreds of volts, and the prospect of probing that with your precious bench instrument is a little nerve-wracking to say the least. The solution to the issue was obvious, build your own isolated high voltage oscilloscope, and here is the Cleverscope CS448 development journey for your viewing pleasure.

The scope itself is specification-wise nothing too flash, it’s the isolated channels that make it special. It does however have some niceties such as an extra eight 100 Mbps digital inputs and a handy 65 MHz signal generator. Also, don’t reach for your wallets just yet, as this is a specialised instrument with an even smaller potential user base than a normal scope, so these units are rather pricey. That all said, it’s not the existence of the scope that is the focus here, it’s the journey from problem to solution that interests us the most. There is much to learn from [Bart’s] journey, for example, where to place the frontend ADC? Isolated side or not? The noise floor of the signal chain dictated the former.

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Minty Tunes Is Wireless Audio In An Altoids Tin

November 18, 2021 by 15 Comments

These days, a lot of phones don’t have audio jacks anymore. It can make it hard to listen to music if your favorite headphones aren’t already wireless-enabled. Minty Tunes solves that problem, combined with a little Altoids tin flair.

Yes, the long and the short of it is that this is a Bluetooth audio receiver built into a tin of mints. The build is relatively simple, hooking up a cheap Bluetooth audio decoder module to a lithium-polymer battery. This is paired with a TP4056 battery charger IC to allow the battery to be topped off easily. It’s all then wired up and stuck in everyone’s favorite hacker electronics enclosure.

For those who aren’t fans of wireless earbuds like AirPods and the like, it’s a useful solution for listening to music from a smartphone. As the builder notes, it’s also a great way to play music over a hi-fi or car stereo with an aux port. Alternatively, you could always build your own pocket MP3 player from scratch. Video after the break.

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Light projected through prisms on to laser-cut letters submerged in water.

YOU Are A Projection Of Your Influences

November 18, 2021 by 5 Comments

Who are you? No, who are you really? You’re an amalgamation of influences from your family, your friends, the media, and the parasocial relationships you have with fictional characters. It’s okay; we all are. It can’t be helped that there’s a lot of it about.

[Kim Pimmel]’s YOU examines this question of identity in the form of  projected typography. YOU are solidly laser-cut at birth, but then come the influences — the water of everyday life that surrounds you, the lights that mask your dread or lay you bare, and the prisms of circumstance that twist the light into brilliant patterns that burn memories into your brain.

In this case, the light comes from a hacked camping headlamp that was past its prime. [Kim] laser-cut the letters from acrylic and submerged them in water, which can be manipulated to enhance the effect and mimic the turmoil of life. For added effect, [Kim] held prisms in the light’s path to refract it and cause the patterns to dance. Be sure to check it out after the break, and don’t forget to turn on the sound so you can hear [Kim]’s original composition.

Want to see more trippy typography? Check out this vector art that started as Perlin noise.

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Privacy Report: What Android Does In The Background

November 18, 2021 by 76 Comments

We’ve come a long way from the Internet of the 90s and early 00s. Not just in terms of technology, capabilities, and culture, but in the attitude most of us take when accessing the ‘net. In those early days most users had a militant drive to keep any personal or identifying information to themselves beyond the occasional (and often completely fictional) a/s/l, and before eBay and Amazon normalized online shopping it was unheard of to even type in a credit card number. On today’s internet we do all of these things with reckless abandon, and to make matters worse most of us carry around a device which not only holds all of our personal information but also reports everything about us, from our browsing habits to our locations, back to databases to be stored indefinitely.

It was always known that both popular mobile operating systems for these devices, iOS and Android, “phone home” or report data about us back to various servers. But just how much the operating systems themselves did was largely a matter of speculation, especially for Apple devices which are doing things that only Apple can really know for sure. While Apple keeps their mysteries to themselves and thus can’t be fully trusted, Android is much more open which paradoxically makes it easier for companies (and malicious users) to spy on users but also makes it easier for those users to secure their privacy on their own. Thanks to this recent privacy report on several different flavors of Android (PDF warning) we know a little bit more on specifically what the system apps are doing, what information they’re gathering and where they’re sending it, and exactly which versions of Android are best for those of us who take privacy seriously.

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Video Gaming Like It’s 1983: New Game Cartridges From Atari

November 18, 2021 by 19 Comments

If you remember anything from 1983, it’s likely to be some of the year’s popular culture highlights, maybe Return of the Jedi, or Michael Jackson’s Thriller. For anyone connected with the video gaming industry though, it’s likely that year will stick in the mind for a completely different reason, as the year of the infamous Great Video Games Crash. Overcapacity in the console market coupled with a slew of low quality titles caused sales to crash and a number of companies to go out of business, and the console gaming world would only recover later in the decade with the arrival of the Japanese 8-bit consoles from Nintendo and Sega. You might expect Atari to shy away from such a painful period of their history, but instead they are embracing it as part of their 50th anniversary and launching three never-released titles on cartridges for their 8-bit 2600 console.

Game footage from Aquaventure.
Game footage from Aquaventure.

The three games, Yars’ Return, Aquaventure, and Saboteur, are all unreleased titles from back in the day that never saw publication because of the crash, and are being released as limited edition specials through AtariXP, a new venture that the company says will offer “previously unreleased titles from Atari’s expansive library, rare-and-hard-to-find Atari IP physical media, and improved versions of classic games“. It’s fairly obviously an exercise in satisfying the collector’s market rather than one of video game publishing, but it will be interesting to see what emerges. In particular we hope someone will tear down one of these cartridges; will they find a set of old-school EPROMs inside or an EPROM emulator sporting a microcontroller and other 2020s trickery?

This is not of course the first time we’ve reported on collectable 2600 cartridges, but these ones haven’t spent 30 years in a landfill site.

Header image: Evan-Amos, Public domain.

Know Audio: Get Into The Groove

November 18, 2021 by 62 Comments

The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Dydric [CC BY-SA 2.5)], via Wikimedia Commons.
The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Photo by Dydric CC-BY-SA 2.5
For me, the vinyl record player is the spiritual home of my audio listening experience, probably because I’m of the last generation to grow up when vinyl was king. The 12″ album, with its full-size sleeve and copious sleeve notes, used to be an integral part of musical enjoyment that hasn’t been adequately replicated in the age of streaming.

And like anyone who became an adult while CD players were still expensive luxury items, I started my journey into Hi-Fi with a turntable set-up that sounded pretty good. Since a new generation have in recent years rediscovered vinyl, it’s once again something that should be part of any review of audio technology.

I would have started this piece with a full run-down of the constituent parts of a good turntable, but since that’s a piece that I wrote back in 2017, it’s time to investigate some of the audiophile claims about vinyl recordings. It’s fair to say that this is an area where a lot of complete rubbish is spouted by people who should know better, and that’s something I find immensely entertaining to poke fun at. Buckle up. Continue reading “Know Audio: Get Into The Groove” →

Star Trek Tap Controller, Take Two

November 18, 2021 by 24 Comments

Engineering student and DIY enthusiast [Xasin] thought that the usual ways of controlling various home devices, such as phone apps and web interfaces, were too boring. Instead, he developed the wearable Tap interface which is a cross between a Star Trek comms badge and mobile holo-emitter. The basic idea is to control stuff by tapping the pendant. But things got a little out of hand since this project started two years ago.

[Xasin] began with Tap version 1 back in 2019, and learned all about coding for BLE, making 3D printed cases, and eventually working out all the kinks in the system. Tap v1 used capacitive touch sensing, but the current version detects physical taps using an accelerometer and also can detect gestures. Feature creep along the way brings a sensor array, an array of emotive LEDs, an OLED screen, and a speaker. The whole thing is powered by a dual-core ESP32 Pico MCU. [Xasin] has published his project on GitHub in case you want to explore some of these other features on your own.

The project is only partially up and running because a few critical components are unavailable due to the global parts shortage. But it will soon be able to control smart home devices, such as [Xasin]’s standalone Dragon’s Home smart home system that we wrote about earlier this year. If you want to learn more about tap controlling in general, check out this article from 2018. You can see the Tap introduce itself and its features in the short video below the break.

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