Ethernet For Hackers: Transformers, MACs And PHYs

March 7, 2024 by 21 Comments

We’ve talked about Ethernet basics, and we’ve talked about equipment you will find with Ethernet. However, that’s obviously not all – you also need to know how to add Ethernet to your board and to your microcontroller. Such low-level details are harder to learn casually than the things we talked about previously, but today, we’re going to pick up the slack.

You might also have some very fair questions. What are the black blocks near Ethernet sockets that you generally will see on boards, and why do they look like nothing else you see on circuit boards ever? Why do some boards, like the Raspberry Pi, lack them altogether? What kind of chip do you need if you want to add Ethernet support to a microcontroller, and what might you need if your microcontroller claims to support Ethernet? Let’s talk.

Transformers Make The Data World Turn

One of the Ethernet’s many features is that it’s resilient, and easy to throw around. It’s also galvanically isolated, which means  you don’t need a ground connection for a link either – not until you want a shield due to imposed interference, at which point, it might be that you’re pulling cable inside industrial machinery. There are a few tricks to Ethernet, and one such fundamental Ethernet trick is transformers, known as “magnetics” in Ethernet context.

Each pair has to be put through a transformer for the Ethernet port to work properly, as a rule. That’s the black epoxy-covered block you will inevitably see near an Ethernet port in your device. There are two places on the board as far as Ethernet goes – before the transformer, and after the transformer, and they’re treated differently. After the transformer, Ethernet is significantly more resilient to things like ground potential differences, which is how you can wire up two random computers with Ethernet and not even think about things like common mode bias or ground loops, things we must account for in audio, or digital interfaces that haven’t yet gone optical somehow.

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CT Scan Reveals Secrets Of Heinz’s New Ketchup Cap

March 7, 2024 by 57 Comments

Ketchup bottles are a solved technology, right? Wrong! As it turns out, there is still great development being done in this space. Industrial imaging company Lumafield reveals to us the secrets of Heinz’s new ketchup bottle cap, reportedly the result of a seven-figure investment and eight long years of toil.

Lumafield put the cap in a CT scanner to generate three-dimensional cutaway images of the cap’s internal structure.  The trick of the new cap is in how it compares to the old design. The previous solution used multiple different plastics: likely polypropylene for the cap itself, along with a small amount of silicone for the flexible nozzle valve. The point of the valve was to regulate the flow of ketchup so the bottle squirts out the red goop in a predictable fashion.

The problem with the old cap is that the use of two materials both makes it more expensive to manufacture, and practically impossible to recycle. A solution was needed, and Heinz finally found one.

The new cap, which is fully recyclable, takes advantage of the properties of ketchup itself. As the ketchup is squeezed out of the bottle, it passes through a complicated array of channels before it gets to the nozzle outlet itself. As a sheer-thinning fluid, ketchup gets less viscous the more its under strain. Thus, as it deforms around the complex channels, it becomes less viscous and more likely to flow out at a predictable rate, rather than in thick gloopy spurts.

It’s amazing to think how much work goes into a simple ketchup cap, and yet, millions of dollars are on the line in projects like these. This isn’t the first time Lumafield used their tech to peel back the layers on a piece of common tech — last year we covered their investigation into what’s inside various AirPod knockoffs.

Stacking Solar Cells Is A Neat Trick To Maximise Efficiency

March 7, 2024 by 51 Comments

Solar power is already cheap and effective, and it’s taking on a larger role in supplying energy needs all over the world. The thing about humanity, though, is that we always want more! Too much, you say? It’s never enough!

The problem is that the sun only outputs so much energy per unit of area on Earth, and solar cells can only be so efficient thanks to some fundamental physical limits. However, there’s a way to get around that—with the magic of tandem solar cells!

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Older Nissan Leafs Lose Their App, Are They The First Of Many?

March 7, 2024 by 103 Comments

There was a time when all you needed to use your car was a key. On older vehicles it was a traditional metal key, on more recent ones it had some kind of RFID chip for the immobilizer. As vehicles have become more and more computers on wheels though, the key has disappeared in favor of an electronic key using RF, and in many cases a smartphone application. It’s even used as a selling point: “Look how amazing our car is, you open it with an app!”

Now the obvious flaw is beginning to show in this strategy, as Nissan Leafs made before 2016 and on the road in the UK are to have their app support withdrawn. The manufacturer cites the withdrawal of 2G services, but this seems a little fishy when you consider that the older networks will continue to exist in some form until 2030.

Frankly, there’s part of us that welcomes this news. On one hand, it affects relatively few early adopters. But at the same time, it has the promise of finally educating a gullible public that while a car may last into its second or third decade, the superfluous technology with which it has been loaded probably won’t. If it makes consumers clamor for longer support, or better built vehicles, it can only be a good thing. We’re guessing stories like this will become increasingly common in the next few years — luckily for Leaf owners, its relatively trivial loss of functionality won’t be the worst among them.

If the carmakers have forgotten how to make a vehicle without the dross, we’d be delighted to remind them.

Header: Kārlis Dambrāns, CC BY 2.0.

Thanks [CampGareth] for the tip.

Fabbing A Fab New Watch Face

March 7, 2024 by 7 Comments

[STR-Alorman] is into vintage watches, particularly Omega Seamaster quartz numbers from the 1980s. Among his favorites is the Seamaster Calypso III, a precious few of which were created in a lovely and rare black-on-black colorway. [STR-Alorman] found one on online, but it had a number of problems including a scratched-up face. Having done a respectable amount of PCB design and assembly, he decided to make a new face and have it fabbed.

The one angle where you can even tell this is a PCB.

After taking scale-referenced photos with a DSLR, [STR-Alorman] created vectors in Illustrator and then ported those to KiCad. He sent two versions to the board house — one with holes at index points, and one without — because he wasn’t sure which would be better for applying the luminization compound that makes them glow. Spoiler alert: it was the one with the cutouts.

Once this was done, [STR-Alorman] reassembled the movement, which doesn’t look easy at all, and involved getting the height of a bit of CA glue just right so as not to interfere with the movement of the date wheel. He replaced the bezel insert, re-luminized the hands, and now has a beautiful timepiece.

We believe only the nerdiest of nerds could tell this is a PCB, and they would need exactly the right light to make that determination. Here’s a watch that leaves no doubt about it.

Best Of Both Worlds: The MacPad

March 6, 2024 by 9 Comments

Despite a growing demand for laptop-tablet hybrid computers from producers like Lenovo, HP, and Microsoft, Apple has been stubbornly withdrawn this arena despite having arguably the best hardware and user experiences within the separate domains of laptop and tablet. Charitably one could speculate that this is because Apple’s design philosophy mandates keeping the user experiences of each separate, although a more cynical take might be that they can sell more products if they don’t put all the features their users want into a single device. Either way, for now it seems that if you want a touchscreen MacBook you’ll have to build one yourself like the MacPad from [Federico].

This project started as simply providing a high-quality keyboard and mouse for an Apple Vision Pro, whose internal augmented reality keyboard is really only up to the task of occasionally inputting a password or short string. For more regular computing, [Federico] grabbed a headless MacBook which had its screen removed. This worked well enough that it triggered another line of thought that if it worked for the Vision Pro it might just work for an iPad Pro as well. Using Apple tools like Sidecar makes this almost trivially easy from a software perspective, although setting up the iPad as the only screen, rather than an auxiliary screen, on the MacBook did take a little more customization than normal.

The build goes beyond the software side of setting this up, though. It also includes a custom magnetic mount so that the iPad can be removed at will from the MacBook, freeing both the iPad for times when a tablet is the better tool and the MacBook for when it needs to pull keyboard duty for the Vision Pro. Perhaps the only downsides are that this only works seamlessly when both devices are connected to the same wireless network and that setting up a headless MacBook without a built-in screen takes a bit of extra effort. But with everything online and working it’s nearly the perfect Apple 2-in-1 that users keep asking for. If you’re concerned about the cost of paying for an iPad Pro and a Macbook just to get a touchscreen, though, take a look at this device which adds a touchscreen for only about a dollar.

Thanks to [Stuart] for the tip!

Harvard Claims Breakthrough In Anode Behavior Of Solid State Lithium Batteries

March 6, 2024 by 20 Comments

One of the biggest issues facing the solid-state lithium-based batteries we all depend upon is of the performance of the anode; the transport of lithium ions and minimization of dendrite formation are critical problems and are responsible for charge/discharge rates and cell longevity. A team of researchers at Harvard have demonstrated a method for using a so-called constriction-susceptible structure on a silicon anode material in order to promote direct metal lithium deposition, as opposed to the predominant alloying reaction. After the initial silicon-lithium alloy layer is formed, subsequent layers are pure lithium. Micrometre-scale silicon particles at the anode constrain the lithiation process (i.e. during charging) where free lithium ions are pushed by the charge current towards the anode area. Because the silicon particles are so small, there is limited surface area for alloying to occur, so direct metal plating of lithium is preferred, but crucially it happens in a very uniform manner and thus does not tend to promote the formation of damaging metal dendrites.

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