Screenshot from the video in question, showing 12:54 of the video, demonstrating how the electrons are being exchanged when circuit is completed

Li-ion Battery Low-Level Intricacies Explained Excellently

December 21, 2021 by 7 Comments

There’s a lot of magic in Lithium-ion batteries that we typically take for granted and don’t dig deeper into. Why is the typical full charge voltage 4.2 V and not the more convenient 5 V, why is CC/CV charging needed, and what’s up with all the fires? [The Limiting Factor] released a video that explains the low-level workings of Lithium-ion batteries in a very accessible way – specifically going into ion and electron ion exchange happening between the anode and the cathode, during both the charge and the discharge cycle. The video’s great illustrative power comes from an impressively sized investment of animation, script-writing and narration work – [The Limiting Factor] describes the effort as “16 months of animation design”, and this is no typical “whiteboard sketch” explainer video.

This is 16 minutes of pay-full-attention learning material that will have you glued to your screen, and the only reason it doesn’t explain every single thing about Lithium-ion batteries is because it’s that extensive of a topic, it would require a video series when done in a professional format like this. Instead, this is an excellent intro to help you build a core of solid understanding when it comes to Li-ion battery internals, elaborating on everything that’s relevant to the level being explored – be it the SEI layer and the organic additives, or the nitty-gritty of the ion and electron exchange specifics. We can’t help but hope that more videos like this one are coming soon (or as soon as they realistically can), expanding our understanding of all the other levels of a Li-ion battery cell.

Last video from [The Limiting Factor] was an 1-hour banger breaking down all the decisions made in a Tesla Battery Day presentation in similarly impressive level of detail, and we appreciate them making a general-purpose insight video – lately, it’s become clear we need to go more in-depth on such topics. This year, we’ve covered a great comparison between supercapacitors and batteries and suitable applications for each one of those, as well as explained the automakers’ reluctance to make their own battery cells. In 2020, we did a breakdown of alternate battery chemistries that aim to replace Li-ion in some of its important applications, so if this topic catches your attention, check those articles out, too!

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Hole-y Keyboard

December 21, 2021 by 13 Comments
Can a keyboard get any more aerodynamic than this? Probably not.

According to Google Translate, kleks is Polish for (and I’m cherry-picking definitions here) the word ‘splash’. Well, [deʃhipu]’s hole-ful and soulful Kleks Keyboard certainly made a splash with me. [deʃhipu] knows what I’m talking about. As I said in Discord, I just love the look of those holes. They’re purely aesthetic and do a nice job of showing off [deʃhipu]’s routing skills.

One might argue that those holes also functional in that they increase aerodynamics and remove a not-insignificant amount of weight for travel considerations. But yeah, they mostly are there to look cool. Upon closer inspection, I saw that the two halves are joined with a series of soldered stitches that are made from a [ggconnector] bent into a u-shape. Now it’s a toss-up as to which is my favorite feature.

It seems that [deʃhipu] is never completely satisfied by this or that keyboard build, and that’s okay. That’s normal. That is . . . a big part of what this hobby is all about. Because honestly, what would be the fun in finding The One? We wonder what will happen when the droplets settle. Will [deʃhipu] be satisfied with the Kleks, or will those stylish holes become un-fillable voids?

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Where The Rubber Meets The Computer

December 21, 2021 by 19 Comments

If you ever get a chance to go to Leiden, take it. It is a beautiful little city that hides some high-power university research. It also boasts the world’s first rubber computer. You won’t be running Crysis on it anytime soon, though. The fledgling computer has memory and can count to two — really more of a state machine. It is easier to watch the video below than try to fully explain it. Or you can read through the actual paper.

If you watch the video, you’ll see that deformation in the corrugated rubber structure is apparently repeatable and represent bits in the machine. Pressing and releasing pressure on the structure forms both input and clock and it is possible for the material to go from state A to B on compression, but when you release pressure, it reaches state C. The compression and the angle of the pressure allow for different input conditions. One example rubber state machine counts how many times you compress the piece of rubber.

What do you do with a piece of smart rubber? We don’t know. Maybe if you wanted shoes to count steps so you could transmit the count once a minute to save on battery? The researchers have admitted they don’t have any specific applications in mind either, but presume someone will want to use their work.

Of course, the video’s title: “The Rubber Computer” is a bit of hyperbole, but we can forgive it. Most people wouldn’t get “The Rubber Finite State Machine.” While mechanical computing might seem a bit passe, turns out at the molecular level it may become very important. Besides, you can make a computer out of cardboard (or simulate that computer in an FPGA or spreadsheet, if you prefer).

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Plastics: Photopolymers For 3D Printing And Beyond

December 21, 2021 by 9 Comments

Chances are good that if you’ve done any 3D printing, it was of the standard fused deposition modeling variety. FDM is pretty simple stuff — get a bit of plastic filament hot enough, squeeze the molten goo out of a fine nozzle, control the position of the nozzle more or less precisely in three dimensions, and repeat for hours on end until your print is done. To the outsider it looks like magic, but to us it’s just another Saturday afternoon.

Resin printing is another thing altogether, and a lot closer to magic for most of us. The current crop of stereolithography printers just have a high-resolution LCD display between a UV light source and a build tank with a transparent bottom. Prints are built up layer by layer by flashing UV light patterns into the tank as a build plate slowly lifts it up from the resin, like some creature emerging from the primordial goo.

Of course it’s all just science, but if there is any magic in SLA printing, surely it’s in the resins used for it. Their nondescript brown plastic bottles and information-poor labels give little clue as to their ingredients, although their hydrocarbon reek and viscous, sticky texture are pretty good clues. Let’s take a look inside the resin bottle and find out what it is that makes the magic of SLA happen.

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Ground Effect Aerodynamics On An RC Car

December 21, 2021 by 3 Comments

Ground effect aerodynamics will return to Formula 1 in a big way in the 2022 season, hopefully washing away the bad taste left in fan’s mouths after the recent controversial season decider. [Engineering After Hours] has experimented with F1 aerodynamics on RC cars before, and decided that it was time to try and implement a proper ground-effect design himself.

The aim of ground effect aerodynamics is to create a constriction for airflow between the bottom of the car and the ground underneath. This constriction accelerates the flow beneath the car, and as per Bernoulli’s principle, causes a corresponding pressure drop, sucking the car down onto the track. Viscosity also plays a role; from the car’s perspective, the road beneath the vehicle is moving backwards at some speed, pulling on the fluid thanks to the boundary layer on the ground itself. This further helps increase the strength of the effect.

A vacuum-formed undertray complete with side skirts was installed on the RC car in order to generate ground effect downforce. A quick test with a leaf blower indicates the system works, and that the side skirts are a key component.

Lateral acceleration was significantly improved by around 20% in testing with the ground effects installed, though [Engineering After Hours] admits that without a wind tunnel, the results aren’t the most scientific. However, with the undertray being relatively lightweight, we suspect the aero elements are likely providing plenty of benefit without too much of a negative effect on acceleration or handling.

Check out some of the other aero experiments [Engineering After Hours] has undertaken, too. Video after the break. Continue reading “Ground Effect Aerodynamics On An RC Car” →

Box with a hole. Camera and Raspberry Pi inside.

A Label Maker That Uses AI Really Poorly

December 21, 2021 by 15 Comments

[8BitsAndAByte] found herself obsessively labeling items around her house, and, like the rest of the world, wanted to see what simple, routine tasks could be made unnecessarily complicated by using AI. Instead of manually identifying objects using human intelligence, she thought it would be fun to offload that task to our AI overlords and the results are pretty amusing.

She constructed a cardboard enclosure that housed a Raspberry Pi 3B+, a Pi Camera Module V2, and a small thermal printer for making the labels. The enclosure included a hole for the camera and a button for taking the picture. The image taken by the Pi is analyzed by the DeepAI DenseCap API which, in theory, should create a label for each object detected within the image. Unfortunately, it doesn’t seem to do that very well and [8BitsAndAByte] is left with labels that don’t match any of the objects she took pictures of. In some cases it didn’t even get close, for example, the model thought an apple was a person’s head and a rotary dial phone was a cup. Go figure. It didn’t really seem to bother her though, and she got a pretty good laugh from the whole thing.

It appears the model detects all objects in the image, but only prints the label for the object it was most certain about. So maybe part of her problem is there were just too many objects in the background? If that were the case, you could probably improve the accuracy of the model by placing the object against a neutral background. That may confuse the AI a lot less and possibly give you better results. Or maybe try a different classifier altogether? Or don’t. Then you could just use it as a fun, gag project at your next get-together. That works too.

Cool project [8BitsAndAByte]! Hey, maybe this is a sign the world will still need some human intelligence after all. Who knows?

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Hydrogen Generation Made Easy

December 20, 2021 by 45 Comments

Even if you never want to generate hydrogen, [Maciej Nowak’s] video (embedded below) is interesting to watch because of the clever way the electrode is formed from stainless steel washers. You’ll need heat shrink tubing, but you ought to have that hanging around anyway. Building the electrode using the techniques in the video results in a lot of surface area which is important for an electrochemical reaction.

A standard rechargeable cell provides power for the generator which resides in a modified plastic bottle. The overall build looks good even though it is all repurposed material.

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