Upper stage of a Japanese H-2A rocket which has been in orbit since 2009. It's one of the largest pieces of orbital debris. (Credit: Astroscale)

Astroscale’s ADRAS-J Satellite Takes Up-Close Photo Of Discarded Rocket Stage

June 18, 2024 by 23 Comments

Although there is a lot of space in Earth orbit, there are also some seriously big man-made objects in those orbits, some of which have been there for decades. As part of efforts to remove at least some of this debris from orbit, Astroscale’s ADRAS-J (“Active Debris Removal by Astroscale-Japan”) satellite has been partaking in JAXA’s Commercial Removal of Space Debris Demonstration (CRD2). After ADRAS-J was launched by a Rocket Lab Electron rocket on February 18, it’s been moving closer to its target, with June 14th seeing an approach by roughly 50 meters, allowing for an unprecedented photo to be made of the H-2A stage in orbit. This upper stage of a Japanese H-2A rocket originally launched the GOSAT Earth observation satellite into orbit back in 2009.

The challenges with this kind of approach is that the orbital debris does not actively broadcast its location, ergo it requires a combination of on-ground and on-satellite tracking to match the orbital trajectory for a safe approach. Here ADRAS-J uses what is called Model Matching Navigation, which uses known visual information to compare it with captured images, to use these to estimate the relative distance to the target.

Although the goal of ADRAS-J is only to study the target from as closely as possible, the next phase in the CRD2 program would involve actively deorbiting this upper stage, with phase start projected to commence in 2026.

Thanks to [Stephen Walters] for the tip.

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Recovering An Agilent 2000a/3000a Oscilloscope With Corrupt Firmware NAND Flash

June 18, 2024 by 21 Comments

Everyone knows that you can never purchase enough projects off EBay, lest boredom might inadvertently strike. That’s why [Anthony Kouttron] got his mitts on an Agilent DSO-X 2014A digital oscilloscope that was being sold as defective and not booting, effectively just for parts. When [Anthony] received the unit, this turned out to be very much the case, with the front looking like it got dragged over the tarmac prior to having the stuffing beaten out of its knobs with a hammer. Fortunately, repairing the broken encoder and the plastic enclosure was easy enough, but the scope didn’t want to boot when powered on. How bad was the damage?

As [Anthony] describes in the article, issues with this range of Agilent DSOs are well-known, with for example the PSU liking to fry the primary side due to soft power button leaving it powered 24/7 with no cooling. The other is corrupted NAND storage, which he confirmed after figuring out the UART interface on the PCB with the ST SPEAr600 ARM-based SoC. Seeing the sad Flash block decompression error from the Windows CE said enough.

This led him down the rabbithole of finding the WinCE firmware images (nuked by Keysight, backed up on his site) for this scope, along with the InfiniiVision scope application. The former is loaded via the bootloader in binary YMODEM mode, followed by installing InfiniiVision via a USB stick. An alternate method is explained in the SPEAr600 datasheet, in the form of USB BootROM, which can also be reached via the bootloader with some effort.

As for the cause of the NAND corruption, it’s speculated that the scope writes to the same section of NAND Flash on boot, with the SPEAr600’s Flash controller documentation not mentioning wear leveling. Whether that’s true or not, at least it can be fixed with some effort even without replacing the NAND Flash IC.

The Guinness Brewery Invented One Of Science’s Most Important Statistical Tools

June 18, 2024 by 12 Comments

The Guinness brewery has a long history of innovation, but did you know that it was the birthplace of the t-test? A t-test is usually what underpins a declaration of results being “statistically significant”. Scientific American has a fascinating article all about how the Guinness brewery (and one experimental brewer in particular) brought it into being, with ramifications far beyond that of brewing better beer.

William Sealy Gosset (aka ‘Student’), self-trained statistician. [source: user Wujaszek, wikipedia]
Head brewer William Sealy Gosset developed the technique in the early 1900s as a way to more effectively monitor and control the quality of stout beer. At Guinness, Gosset and other brilliant researchers measured everything they could in their quest to optimize and refine large-scale brewing, but there was a repeated problem. Time and again, existing techniques of analysis were simply not applicable to their gathered data, because sample sizes were too small to work with.

While the concept of statistical significance was not new at the time, Gosset’s significant contribution was finding a way to effectively and economically interpret data in the face of small sample sizes. That contribution was the t-test; a practical and logical approach to dealing with uncertainty.

As mentioned, t-testing had ramifications and applications far beyond that of brewing beer. The basic question of whether to consider one population of results significantly different from another population of results is one that underlies nearly all purposeful scientific inquiry. (If you’re unclear on how exactly the t-test is applied and how it is meaningful, the article in the first link walks through some excellent and practical examples.)

Dublin’s Guinness brewery has a rich heritage of innovation so maybe spare them a thought the next time you indulge in statistical inquiry, or in a modern “nitro brew” style beverage. But if you prefer to keep things ultra-classic, there’s always beer from 1574, Dublin castle-style.

PCB Design Review: Switching Regulator Edition

June 18, 2024 by 18 Comments

This article was prompted by a friend of mine asking for help on a board with an ESP32 heart. The board outputs 2.1 V instead of 3.3 V, and it doesn’t seem like incorrectly calculated feedback resistors are to blame – let’s take a look at the layout. Then, let’s also take a look at a recently sent in design review entry, based on an IC that looks perfect for all your portable Raspberry Pi needs!

What Could Have Gone Wrong?

Here’s the board in all its two-layer glory. This is the kind of board you can use to drive 5 V or 12 V Neopixel strips with a firmware like WLED – exactly the kind of gadget you’ll want to use for LED strip experiments! 3.3 V power is provided by a Texas Instruments TPS54308 IC, and it’s the one misfiring, so let’s take a look.

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TDK Claims Solid State Battery With 100X Energy Density

June 18, 2024 by 49 Comments

Regulations surrounding disposable batteries have accelerated a quiet race to replace coin cells, which on the whole are not readily rechargeable. TDK produces solid-state batteries and has announced a new material that claims an energy density of about 100 times that of their conventional batteries.

Energy density measures how much energy a system contains relative to its volume. The new battery has 1000 Wh/L. For comparison, old nickel-cadmium cells had about 150 Wh/L. A typical lithium-ion battery usually turns in about 200 – 250 Wh/L.

There aren’t many technical details, but a few things caught our interest. For one, it uses an oxide-based solid electrolyte and lithium alloy anodes. However, what really caught our eye was that it is “intended for use in wearables… that come in direct contact with the human body.” We don’t know if that means the material is safe for your skin or if it depends on being next to your body to operate.

While the energy density is high, keep in mind that the batteries of this type are usually tiny, so the total actual power available is probably not very high. Tiny batteries are definitely a thing. We are always hearing about breakthroughs, but we always wonder if and when we’ll see actual products.

McDonald’s Terminates Its Drive-Through Ordering AI Assistant

June 18, 2024 by 72 Comments

McDonald’s recently announced that it will be scrapping the voice-assistant which it has installed at over 100 of its drive-throughs after a two-year trial run. In the email that was sent to franchises, McDonald’s did say that they are still looking at voice ordering solutions for automated order taking (AOT), but it appears that for now the test was a disappointment. Judging by the many viral videos of customers struggling to place an order through the AOT system, it’s not hard to see why.

This AOT attempt began when in 2019 McDonald’s acquired AI company Apprente to create its McD Tech Labs, only to sell it again to IBM who then got contracted to create the technology for McDonald’s fast-food joints. When launched in 2021, it was expected that McDonald’s drive-through ordering lanes would eventually all be serviced by AOT, with an experience akin to the Alexa and Siri voice assistants that everyone knows and loves (to yell at).

With the demise of this test at McDonald’s, it would seem that the biggest change is likely to be in the wider automation of preparing fast-food instead, with robots doing the burger flipping and freedom frying rather than a human. That said, would you prefer the McD voice assistant when going through a Drive-Thru® over a human voice?

A Brief Look Inside A Homebrew Digital Sampler From 1979

June 17, 2024 by 12 Comments

While we generally prefer to bring our readers as much information about a project as possible, sometimes we just have to go with what we see. That generally happens with new projects and work in progress, but it can also happen with old projects. Sometimes very old indeed, as is the case with this digital sampling unit for analog oscilloscopes, circa 1979.

We’ve got precious little to go on with this one other than the bit of eye candy in the video tour below and its description. Luckily, we’ve had a few private conversations with its maker, [Mitsuru Yamada], over the years, enough to piece together a little of the back story here — with apologies for any wrong assumptions, of course.

Built when he was only 19, this sampler was an attempt to build something that couldn’t be bought, at least not for a reasonable price. With no inexpensive monolithic analog-to-digital converters on the market, he decided to roll his own. A few years back he recreated the core of that with his all-discrete successive approximation ADC.

The sampler shown below has an 8-bit SAR ADC using discrete CMOS logic and enough NMOS memory to store 256 samples. You can see the ADC and memory cards in the homebrew card cage made from aluminum angle stock. The front panel has a ton of controls and sports a wide-range attenuator, DC offset, and trigger circuit with both manual and automatic settings.

It’s an impressive build, especially for a 19-year-old with presumably limited resources. We’ve reached out to [Yamada-san] in the hope that he’ll be able to provide more details on what’s under the hood and if this still works after all these years. We’ll pass along whatever we get, but in the meantime, enjoy.

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