Punycodes Explained

January 18, 2023 by 18 Comments

When you’re restricted to ASCII, how can you represent more complex things like emojis or non-Latin characters? One answer is Punycode, which is a way to represent Unicode characters in ASCII. However, while you could technically encode the raw bits of Unicode into characters, like Base64, there’s a snag. The Domain Name System (DNS) generally requires that hostnames are case-insensitive, so whether you type in HACKADAY.com, HackADay.com, or just hackaday.com, it all goes to the same place.

[A. Costello] at the University of California, Berkley proposed the idea of Punycode in RFC 3492 in March 2003. It outlines a simple algorithm where all regular ASCII characters are pulled out and stuck on one side with a separator in between, in this case, a hyphen. Then the Unicode characters are encoded and stuck on the end of the string.

First, the numeric codepoint and position in the string are multiplied together. Then the number is encoded as a Base-36 (a-z and 0-9) variable-length integer. For example, a greeting and the Greek for thanks, “Hey, ευχαριστώ” becomes “Hey, -mxahn5algcq2″. Similarly, the beautiful city of München becomes mnchen-3ya. Continue reading “Punycodes Explained” →

Spray-On Keyboard Is As Light As It Gets

January 18, 2023 by 19 Comments

We’ve all seen those ‘nothing’ keyboards, where the keys themselves are not much more than projected lasers, and users are asked to ritually beat their poor fingertips into the table — which has little give and even less clack. Well, a team at the Korea Advanced Institute of Science and Technology have come up with a way to eschew the keyboard altogether.

Essentially, the user wears a thin, breathable mesh of silver nanowires coated in gold, which is then embedded in a polyurethane coating. The mesh is sprayed onto their forearms and hands on the spot, and the mesh terminates in a small enclosure that is also worn on the skin. This contains a small Bluetooth unit that beams data back to a computer, a machine, or potentially another user wearing the same type of unit.

As the skin stretches and contorts, the mesh senses small electrical changes within. These changes become meaningful with applied AI, which maps the changes to specific gestures and manual tasks. To do this, the team started with teaching it to distinguish between patterns from tasks like typing on a phone, typing on a regular keyboard, and then holding and interacting with six differently-shaped simple objects.

The team isn’t stopping there — they plan to try capturing a larger range of motion by using the nanomesh on multiple fingers. In addition to facilitating communication between humans and machines, this could leave a huge fingerprint on gaming and VR.

Grass Gauge Tells You When The Lawnmower’s Catcher Is Full

January 18, 2023 by 20 Comments

If you’re not mowing your lawn regularly, you’re probably familiar with the hassle of overfilling your catcher. Grass clippings end up scattered everywhere, and you end up with a messy yard after all your hard work. [Dominic Bender] designed a mower fill gauge to eliminate this problem which shows you when your catcher is getting full.

The concept behind the gauge’s operation is simple. Catcher-based mowers rely on airflow from the spinning blades to carry grass into the catcher. That airflow is, in this case, also used to push up a flap mounted in the top of the catcher. As the catcher fills with grass, that airflow no longer reaches the flap, which sinks down, indicating the catcher is getting full. The basic design is a simple 3D printed flap and housing that uses a short piece of filament as a hinge. There’s also a small mesh guard to stop the flap getting clogged by the incoming grass clippings.

If you’re the forgetful sort, or your enthusiastic children aren’t always emptying the catcher when they should, this gauge might be a useful tool for you. Alternatively, consider robotizing your mowing in the vein of other builds we’ve seen, including one by yours truly. If you’ve got your own nifty gardening hacks, be sure to drop us a line!

One-Size-Fits-All Wrench Points To A Nut Job

January 17, 2023 by 37 Comments

When [Hand Tool Rescue] came across a 1919 patent for a one size fits all wrench, he couldn’t help but recreate it. Described in the patent as “a new, original, ornamental design for a wrench”, the wrench had a slot for possibly every fastener that the inventor could think of. Not only did it have slots for several hexagonal fasteners, but many others for octagonal, square and even a pentagonal fastener.

[Hand Tool Rescue] reckons there are 47 slots for various sizes and types of fasteners, not counting the ones whose purpose he could not fathom. Just in case he missed any fastener sizes, the original designer decided to add an alligator wrench at the other end of the handle, potentially negating the need for any of the other slots. The tool even features a sharp edge along one of the sides, possibly for use as a scraper of some kind.

Why such a crazy design was patented, or what were the functions of some of its slots are questions that will likely remain unanswered. At best, we can all take guesses at solving the mystery of this tool. [Hand Tool Rescue] scales the original drawing such that one of the slots has a width of 1 inch, and then uses that as a template to recreate the wrench. He starts with a slab of 3/8th inch thick, grade 4140 steel, which has a high strength to weight ratio and can be case hardened after machining, making it suitable for this ornamental project.

He then embarks on his journey of excessive milling, drilling, filing, band sawing and shaping (using a slotting attachment), totaling about 11 hours worth of drudgery. Of course, one could argue that it would have been much easier, and accurate, to have used modern machining methods. And we are spoilt for choices here among laser cutting, water jet cutting or even EDM machining, any of which would have done the job faster, cleaner and more precisely. But we guess [Hand Tool Rescue] wanted to stick to traditional methods as would have been available in 1919 to an inventor who wanted to make a prototype of his awesome, all in one wrench.

If you can help explain the overall function of this wrench, or identify some of the more vague slots in it, then [Hand Tool Rescue] would be happy to get the feedback. And talking about less desirable wrenches, check out how this Sliding Wrench Leaves a Little to be Desired.

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Turns Out, Lightning Can Strike Twice, With A Little Help

January 17, 2023 by 19 Comments

Few things are more impressive than a lighting strike. Lightning can carry millions of volts and while it can be amazing to watch, it is somewhat less amazing to be hit by lightning. Rockets and antennas often have complex lightning protection systems to try to coax the electricity to avoid striking where you don’t want it. However, a European consortium has announced they’ve used a very strong laser to redirect lightning in Switzerland. You can see a video below, but you might want to turn on the English closed captions.

Lightning accounts for as many as 24,000 deaths a year worldwide and untold amounts of property and equipment damage. Traditionally, your best bet for protection was not to be the tallest thing around. If the tallest thing around is a pointy metal rod in the ground, that’s even better. But this new technique could guide lightning to a specific ground point to have it avoid causing problems. Since lightning rods protect a circular area roughly the radius of their height, having a laser that can redirect beams to the area of a lightning rod would allow shorter rods to protect larger areas.

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Kirby Sucks, Literally

January 17, 2023 by 8 Comments

What’s common between one of the most legendary video game characters of all time and a fume extractor ? They both suck. [Chris Borge] is not an electronics hobbyist and only does some occasional soldering. This made his regular fume extractor bulky and inconvenient to position where needed. What could serve him better would be a small extractor that could be attached to a clip or an arm on his helping hand accessory. Being unable to find an off-the-shelf product or a suitable 3d printed design that he liked, he built the Kirby 40mm Fume Extractor.

His initial idea was for a practical design more suited to his specific needs. But somewhere along the way, the thought of a Kirby fan popped up in his head, and it was too good an idea to pass up. Several Kirby fan designs already existed, but none that satisfied [Chris]. Getting from paper sketch to CAD model required quite an effort but the result was worth the trouble, and the design was quite faithful to the original character features. The main body consists of two halves that screw together, and an outlet grill at the back. The body has space for a 40 mm fan and a 10 mm charcoal filter in the front. The wires come out the back, and connect directly to a power supply barrel jack. Arms and eyes are separate pieces that get glued to the body. The feet glue to an intermediate piece, which slides in a dove tail grove in the body. This allows Kirby to be tilted at the right position for optimum smoke extraction.

While Kirby served the purpose, it still didn’t meet the original requirement of attaching to a clip or arm on the helping hand. So [Chris] quickly designed a revised, no-frills model which is essentially a square housing to hold the fan and the filter. It has a flexible stand so it can be placed on a bench. And it can also be attached to the helping hand, making it a more utilitarian design. This design has the charcoal filter behind the fan, but he also has a third design for folks who prefer to have the filter at the front.

He now had a more useful, practical fume extractor, but he couldn’t bring himself to discard his original Kirby. So he printed a couple more 3D parts so that Kirby could fit the end of his vacuum cleaner hose. Now, Kirby sits on his bench, and helps suck up all the bits and bobs of trash on his workbench. We’re sure Kirby is quite pleased with his new role.

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A man sits in a chair atop a hexagonal platform. From the platform there are six hydraulically-actuated legs supporting the hexapod above a grassy field. The field is filled with fog, giving the shot a mysterious, otherworldly look.

Megahex Will Give You Robo-Arachnophobia

January 17, 2023 by 24 Comments

Some projects start with a relatively simple idea that quickly turns into a bit of a nightmare when you get to the actual implementation. [Hacksmith Industries] found this to be the case when they decided to build a giant rideable hexapod, Megahex. [YouTube]

After seeing a video of a small excavator that could move itself small distances with its bucket, the team thought they could simply weld six of them together and hook them to a controller. What started as a three month project quickly spiraled into a year and a half of incremental improvements that gave them just enough hope to keep going forward. Given how many parts had to be swapped out before they got the mech walking, one might be tempted to call this Theseus’ Hexapod.

Despite all the issues getting to the final product, the Megahex is an impressive build. Forward motion and rotation on something with legs this massive is a truly impressive feat. Does the machine last long in this workable, epic state? Spoilers: no. But, the crew learned a lot and sometimes that’s still a good outcome from a project.

If you’re looking for more hexapod fun, checkout Stompy, another rideable hexapod, or Megapod, a significantly smaller 3D-printed machine.

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