The Science Behind The Majesty Of Dancing Raisins

Have you ever thrown a handful of raisins into a tub of sparkling water? Or peanuts into beer? It seems like an altogether strange thing to do, but if you’ve tried it, you’ll have seen the way the raisins dance and tumble in the fluid. As it turns out, there’s some really interesting science at play when you dive into the mechanics of it all. [Saverio Spagnolie] did just that, and even went as far as publishing a paper on the topic.

The fundamental mechanism behind the dancing raisins is down to the bubbles in sparkling water. When dropped into the fluid, bubbles form on the raisins and attach to them, giving them additional buoyancy.  They then float up, with some of the bubbles shedding or popping on the way, others doing so at the fluid surface. This then causes the raisins to lose buoyancy, rotate, flop around, and generally dance for our amusement.

[Saverio] didn’t just accept things at face value though, and started taking measurements. He used 3D-printed models to examine bubble formation and the forces involved. Along with other scientists, models were developed to explore bubble formation, shedding, and the dynamics of raisin movement. If you don’t have time to dive into the paper, [Saverio] does a great job of explaining it in a Twitter thread (Nitter) in an accessible fashion.

It’s a great example of cheap kitchen science that can teach you all kinds of incredible physics if you just care to look. Video after the break.

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Beautiful lamp made from recycled can

Another Way To Recycle Those Empty Beverage Cans

Do you ever sit around thinking of ways to repurpose things in your house? Well [BevCanTech] found a way to recycle some of his empty beverage cans by turning them into homemade wire.

Beautiful, decorative, and functional lamp made from soda can. Also showing the positive and negative voltage terminals.

The premise is simple. He cut 2 mm thick strips of wire from the beverage can along its circumference, creating a thin, long “wire” spool. He sanded the ends of each strip to crimp pieces of his homemade wire together. He found he could get about four meters from a standard-sized beverage can, probably roughly 12 oz, as he unraveled the can. He then used crimp connectors to connect his homemade wires to the battery terminals and also to the end of a flashlight. He used a red cap from another can as a pseudo light diffuser and lampshade, creating a pretty cool, almost lava lamp-like glow.

Maybe the meat of this project won’t be as filling as your Thanksgiving meal, but hopefully, it can serve as a bit of inspiration for your next freeform circuit design. Though you’ll probably want to smooth those sharp edges along your homemade wire.

Centaur Costume Features Drinks Cooler And Walking Legs

Let’s say it’s Halloween, and you’re a big fan of centaurs. At the same time, you want to be easily able to store your drinks on ice and always have them to hand. Well, this costume from [David Yakos] might be the one for you.

Construction is simple. Two small bike wheels were fitted to the cooler using bits of a broken chair, and the other end of the cooler is simply fitted around the wearer’s waist with a strap.

The rear centaur legs are carved out of foam board, and attached to the rear wheels with a bolt through the spokes. The top of each leg is attached to a rod, which slides into the frame holding the wheels on. It keeps the top of the legs roughly where they should be but lets them move, allowing the legs to “walk” as the wheels rotate.

It’s not exactly an advanced build, but we simply love the idea of costumes that keep drinks cold all night. Hiding the cooler as a centaur’s body is really just the icing on the cake. Of course, if you’ve got your own costume design for keeping your beverages chilled and frosty, do let us know. Video after the break.

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Alexa, Bring Me A Beer!

Voice controlled home assistants are the wonder of our age, once you’ve made peace with the privacy concerns of sharing the intimacies of your life with a data centre owned by a massive corporation, anyway. They provide a taste of how the future was supposed to be in those optimistic predictions of decades past: Alexa and Siri can crack jokes, control your lights, answer questions, tell you the news, and so much more.

But for all their electronic conversational perfection, your electronic pals can’t satisfy your most fundamental needs and bring you a beer. This is something [luisengineering] has fixed, an he’s provided the appropriate answer to the question “Alexa: bring mir ein bier!“. The video which we’ve also put below the break is in German with YouTube’s automatic closed captions if you want them, but we think you’ll be able to get the point of it if not all his jokes without needing to learn to speak a bit of Deutsch.

As he develops his beer-delivery system we begin to appreciate that what might seem to be a relatively straightforward task is anything but. He takes an off-the-shelf robot and gives it a beer-bottle grabber and ice hopper, but the path from fridge to sofa still needs a little work. The eventual solution involves a lot of trial and error, and a black line on the floor for the ‘bot to follow. Finally, his electronic friend can bring him a beer!

We like [Luis]’s entertaining presentational style, and the use of props as microphone stands. We’ll be keeping an eye out for what he does next, and you should too. Meanwhile it may not surprise you that this is not the first beer-delivery ‘bot we’ve brought you.

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Over-Engineered Bottle Opener Takes The Drudgery Out Of Drinking

Some projects take but a single glance for you to know what inspired them in the first place. For this over-engineered robotic bottle opener, the obvious influence was a combination of abundant free time and beer. Plenty of beer.

Of course there are many ways to pop the top on a tall cold one, depending on the occasion. [Matt McCoy] and his cohorts selected the “high-impulse” method, which when not performed by a robot is often accomplished by resting the edge of the cap on a countertop and slapping the bottle down with the palm of one’s hand. This magnificently pointless machine does the same thing, except with style.

The bottle is placed in a cradle which grips it, gently but firmly, and presents it to the opening mechanism in a wholly unnecessary motion-control ballet. Once in place, a lead screw moves a carriage down, simultaneously storing potential energy in a bundle of elastic surgical tubing while tripping a pawl on the edge of the cap. A lever trips at the bottom of the carriage’s travel, sending the pawl flying upward to liberate the libation, giving the robot a well-deserved and sudsy showers. Behold the wonderful interplay of 190 custom parts — and beer — in the video below.

Hats off to [Matt] et al for their tireless efforts on behalf of beleaguered beer-openers everywhere. This seems like the perfect accessory to go along with a game of mind-controlled beer pong.

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Voice Controlled Sofa Meets Your Every Beverage Need

It’s often taken for grated, but the modern world is full of luxuries. Home automation, grocery delivery, and even access to the Internet are great tools to have at hand, but are trivial to most of us. If these modern wonders are not enough for you, and the lap of luxury is still missing a certain je ne sais quoi, allow us to introduce you to the ultimate convenience: a voice controlled, beer-dispensing sofa with a built-in refrigeration system.

This is a project from [Garage Avenger] and went through a number of iterations before reaching this level of polish. Metal work on the first version didn’t fit together as expected, and there were many attempts at actual refrigeration before settling on repurposing an actual refrigerator. With those things out of the way, he was able to get to the meat of a project. The couch-refrigerator holds 12 beers, and they are on a conveyor belt which automatically places the next beer onto the automated drawer. When commanded (by voice, app, or remote) the sofa opens the drawer so the occupant can grab one easily without having to move more than an arm. Everything, including the voice recognition module, is controlled by an Arduino, as is tradition.

The attention to detail is excellent as well. The remote control contains a built-in bottle opener, for one, there are backlights and a glass cover for the refrigerator, and the drawer is retracted automatically when it senses the beer has been obtained. We couldn’t ask for much more from our own couches, except maybe that they take us where we want to go. But maybe it’s best to keep these two couch use cases separate for now.

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The Auto-Bartender

It’s the end of the academic semester for many students around the globe, so here comes the flurry of DIY projects. Always a great time to check out all the cool hacks from our readers all over the world. One project that piques our interest comes courtesy of [Jason Ummel] and his Auto-Bartender. (Video, embedded below.)

[Jason] developed this project as a part of his robotics class taught by Professor Martinez, one of our friends at FlexiLab. Powered by one of our favorite microcontrollers, the ATmega328, the Auto-Bartender is driven by a single 12 V motor coupled with 10 individual valves for separate drinks. Drinks are pumped into a cup sitting on top of a scale, allowing the device to know how much of each drink has been dispensed. The entire setup is controlled using a smartphone application developed in MIT App Inventor, a super-easy way to prototype Android applications.

Furthermore, [Jason] incorporated a number of user-centered design considerations into his project. These include an LCD to display updates, a green LED to indicate the device is in progress, and a buzzer to let the user know the drink is complete.

We really like the combination of craftsmanship, electronics hardware design, and software development that [Jason] put into his project. It’s the kind of project we know our readers will enjoy.

It looks like Jason substituted tap water for Whiskey and Dr. Pepper for his demo. Not exactly what we had in mind, but I guess he still has exams to finish.

Cool project [Jason]! We can’t wait to see Auto-Bartender on Hackaday.io.

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