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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The Assassin’s Teapot Is A Mischievous Design

December 20, 2021 by 31 Comments

Many films use a similar trope when it comes to poisoning. The aspiring murderer ingests a drink poured from the same vessel as that given to their intended victim to indicate the liquid is safe to imbibe. The Assassin’s Teapot is a way one could achieve such a ruse, allowing two different liquids to be poured from what is seemingly a regular teapot, as shown by [Steve Mould]. (Video after the break.)

The trick is simple. Two separate cavities exist within the teapot, exiting via their own paths in the same spout. Each cavity also has an air hole in the top. If the hole for a given cavity is blocked by the pourer’s thumb, the liquid will not flow.

Each cavity can be filled with its own liquid. For example, one can be filled with tea, the other with poisoned tea. The murderer blocks the hole for the poison cavity when pouring their own beverage, delivering tea to their own glass. Then, when pouring for the enemy, the hole for the tea cavity is blocked, and poison is allowed to flow into the glass of one’s target.

The workings are simple; if air cannot flow into the cavity of the teapot to replace liquid flowing out, air pressure will stop the liquid flowing at all. The concept is demonstrated ably by [Steve]’s 2D recreation, letting us visualize the workings of the teapot quite easily.

It also shows a minor flaw in the design, which should be accounted for –  if the spout isn’t designed carefully, sometimes flow from one cavity can dribble into the other. Between this and the chance of getting confused about which hole to cover to pour the poison, it would pay to keep some antidote on hand. Or, alternatively, just pour your guests tea instead – they’ll appreciate it!

We’ve seen [Steve] explore similarly interesting liquid vessels before too, such as this simple breakdown of the workings of the Gluggle Jug.

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