Your Favorite Basic Oscilloscope Operation Guide?

February 8, 2025 by Maya Posch 9 Comments

Like many pieces of lab equipment, oscilloscopes are both extremely useful and rather intimidating to a fledgling user. Unlike a digital multimeter with its point-and-measure functionality, digital storage oscilloscopes (DSOs) require fundamental knowledge before they can be used properly. Yet at the same time nobody likes reading manuals, so what is one to do? Try the Absolute Beginner’s Guide to DSOs by [Arthur Pini]

[Pini’s] Cliff’s Notes version of your scope’s manual isn’t half bad. It covers the basic user interface and usage of a (stand-alone) DSO. Unfortunately, it focuses a bit too much on a fancy touch-screen Teledyne LeCroy MSO rather than something the average hobbyist is likely to have lying around.

We rather like the PSA-type videos such as the classic ‘“How not to blow up your oscilloscope” video by [Dave] over at EEVBlog. Many guides and introductions cover “what to do,” but covering common safety issues like improper grounding, isolation, or voltages might be a better place to start.

What tutorial or reference work would you hand to an oscilloscope newbie? We can endorse a hands-on approach with a suitable test board. We also enjoyed [Alan’s] video on the topic. Even if you are an old hand, do you know how to use all those strange trigger modes?

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Freed At Last From Patents, Does Anyone Still Care About MP3?

February 8, 2025 by Maya Posch 99 Comments

The MP3 file format was always encumbered with patents, but as of 2017, the last patent finally expired. Although the format became synonymous with the digital music revolution that started in the late 90s, as an audio compression format there is an argument to be made that it has long since been superseded by better formats and other changes. [Ibrahim Diallo] makes that very argument in a recent blog post. In a world with super fast Internet speeds and the abstracting away of music formats behind streaming services, few people still care about MP3.

The last patents for the MP3 format expired in 2012 in the EU and 2017 in the US, ending many years of incessant legal sniping. For those of us learning of the wonders of MP3 back around ’98 through services like Napster or Limewire, MP3s meant downloading music on 56k dialup in a matter of minutes to hours rather than days to weeks with WAV, and with generally better quality than Microsoft’s WMA format at lower bitrates. When portable media players came onto the scene, they were called ‘MP3 players’, a name that stuck around.

But is MP3 really obsolete and best forgotten in the dustbin of history at this point? Would anyone care if computers dropped support for MP3 tomorrow?

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Growing A Gallium-Arsenide Laser Directly On Silicon

February 7, 2025 by Maya Posch 10 Comments

As great as silicon is for semiconductor applications, it has one weakness in that using it for lasers isn’t very practical. Never say never though, as it turns out that you can now grow lasers directly on the silicon material. The most optimal material for solid-state lasers in photonics is gallium-arsenide (GaAs), but due to the misalignment of the crystal lattice between the compound (group III-V) semiconductor and silicon (IV) generally separate dies would be produced and (very carefully) aligned or grafted onto the silicon die.

Naturally, it’s far easier and cheaper if a GaAs laser can be grown directly on the silicon die, which is what researchers from IMEC now have done (preprint). Using standard processes and materials, GaAs lasers were grown on industry-standard 300 mm silicon wafers. The trick was to accept the lattice mismatch and instead focus on confining the resulting flaws through a layer of silicon dioxide on top of the wafer. In this layer trenches are created (see top image), which means that when the GaAs is deposited it only contacts the Si inside these grooves, thus limiting the effect of the mismatch and confining it to within these trenches.

There are still a few issues to resolve before this technique can be prepared for mass-production, of course. The produced lasers work at 1,020 nm, which is a shorter wavelength than typically used, and there are still some durability issues due to the manufacturing process that have to be addressed.

Running Doom On An Apple Lightning To HDMI Adapter

February 6, 2025 by Maya Posch 26 Comments

As a general rule of thumb, anything that has some kind of display output and a processor more beefy than an early 90s budget PC can run Doom just fine. As [John] AKA [Nyan Satan] demonstrates in a recent video, this includes running the original Doom on an Apple Lightning to HDMI Adapter. These adapters were required after Apple moved to Lightning from the old 30-pin connector which had dedicated pins for HDMI output.

As the USB 2.0 link used with Lightning does not have the bandwidth for 1080p HDMI, compression was used, requiring a pretty beefy processor in the adapter. Some enterprising people at the time took a hacksaw to one of these adapters to see what’s inside them and figure out the cause of the visual artifacts. Inside is a 400 MHz ARM SoC made by Samsung lovingly named the S5L8747. The 256 MB of RAM is mounted on top of the package, supporting the RAM disk that the firmware is loaded into.

Although designed to only run the Apple-blessed firmware, these adapters are susceptible to the same Checkm8 bootROM exploit, which enables the running of custom code. [John] adapted this exploit to target this adapter, allowing this PoC Doom session to be started. As the link with the connected PC (or Mac) is simply USB 2.0, this presumably means that sending keyboard input and the like is also possible, though the details are somewhat scarce on this aspect.

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Sleeping arctic fox (Alopex lagopus). (Credit: Rama, Wikimedia)

Investigating Why Animals Sleep: From Memory Sorting To Waste Disposal

February 5, 2025 by Maya Posch 19 Comments

What has puzzled researchers and philosophers for many centuries is the ‘why’ of sleep, along with the ‘how’. We human animals know from experience that we need to sleep, and that the longer we go without it, the worse we feel. Chronic sleep-deprivation is known to be even fatal. Yet exactly why do we need sleep? To rest our bodies, and our brains? To sort through a day’s worth of memories? To cleanse our brain of waste products that collect as neurons and supporting cells busily do their thing?

Within the kingdom of Animalia one constant is that its brain-enabled species need to give these brains a regular break and have a good sleep. Although what ‘sleep’ entails here can differ significantly between species, generally it means a period of physical inactivity where the animal’s brain patterns change significantly with slower brainwaves. The occurrence of so-called rapid eye movement (REM) phases is also common, with dreaming quite possibly also being a feature among many animals, though obviously hard to ascertain.

Most recently strong evidence has arisen for sleep being essential to remove waste products, in the form of so-called glymphatic clearance. This is akin to lymphatic waste removal in other tissues, while our brains curiously enough lack a lymphatic system. So is sleeping just to a way to scrub our brains clean of waste?

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Hacking The 22€ BLE SR08 Smart Ring With Built-In Display

February 5, 2025 by Maya Posch 30 Comments

In the process of making everything ‘smart’, it would seem that rings have become the next target, and they keep getting new features. The ring that [Aaron Christophel] got his mittens on is the SR08, which appears to have been cloned by many manufacturers at this point. It’s got an OLED display, 1 MB Flash and a Renesas DA14585 powering it from a positively adorable 16 mAh LiPo battery.

The small scale makes it an absolute chore to reverse-engineer and develop with, which is why [Aaron] got the €35 DA14585 development kit from Renesas. Since this dev kit only comes with a 256 kB SPI Flash chip, he had to replace it with a 1 MB one. The reference PDFs, pinouts and custom demo firmware are provided on his GitHub account, all of which is also explained in the video.

Rather than hack the ring and destroy it like his first attempts, [Aaron] switched to using the Renesas Software Update OTA app to flash custom firmware instead. A CRC error is shown, but this can be safely ignored. The ring uses about 18 µA idle and 3 mA while driving the display, which is covered in the provided custom firmware for anyone who wants to try doing something interesting with these rings.

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Freedesktop And Alpine Linux Looking For New Hosting

February 4, 2025 by Maya Posch 37 Comments

A well-known secret in the world of open source software is that many projects rely on donated hosting for everything from their websites to testing infrastructure. When the company providing said hosting can no longer do so for whatever reason, it leaves the project scrambling for a replacement. This is what just happened for Alpine Linux, as detailed on their blog.

XKCD's dependency model — Modern-day infrastructure, as visualized by XKCD. (Credit: Randall Munroe)

Previously Equinix Metal provided the hosting, but as they are shutting down their bare-metal services, the project now has to find an alternative. As described in the blog post, this affects in particular storage services, continuous integration, and development servers.

As if that wasn’t bad enough, Equinix was also providing hosting for the Freedesktop.org project. In a post on their GitLab, [Benjamin Tissoires] thanks the company for supporting them as long as they have, and details the project’s current hosting needs.

As the home of X.org and Wayland (and many more), the value of Freedesktop.org to the average user requires no explanation. For its part, Alpine Linux is popular in virtualization, with Docker images very commonly using it as a base. This raises the uncomfortable question of why such popular open source projects have to depend on charity when so many companies use them, often commercially.

We hope that these projects can find a new home, and maybe raise enough money from their users to afford such hosting themselves. The issue of funding (F)OSS projects is something that regularly pops up, such as the question of whether FOSS bounties for features are helpful or harmful.