Hurricane Simulator Buoys Research

They say an ounce of prevention is worth a pound of cure. In this case, 38,000 gallons of seawater is worth an un-quantifiable amount of knowledge about hurricanes. At the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, [Brian Haus] and his colleagues study hurricanes using a simulator–an enclosed glass tank about the size of a lap-swimming pool. With the flip of a switch, a 1700 hp fan can create winds up to 200 miles per hour—stronger than a baseline category 5 hurricane.

Although there’s currently no cure for hurricanes, understanding how they work goes a long way in forecasting their intensity. Scientists know that hurricanes are fueled by the ocean’s warmth, but there’s still plenty of mystery to them. By studying what happens where the wind meets the water, they think they’ll figure out how surface factors like sea spray and bubbles affect a storm’s intensity and drag coefficient. Surf the break to catch the wave tank in action.

Until there’s a cure for hurricanes, we’ll just have to live with them and engineer our structures to withstand them.

Continue reading “Hurricane Simulator Buoys Research”

Step The Halbach From My Magnets

[Klaus Halbach] gets his name attached to these clever arrangements of permanent magnets but the effect was discovered by [John C. Mallinson]. Mallinson array sounds good too, but what’s in a name? A Halbach array consists of permanent magnets with their poles rotated relative to each other. Depending on how they’re rotated, you can create some useful patterns in the overall magnetic field.

Over at the K&J Magnetics blog, they dig into the effects and power of these arrays in the linear form and the circular form. The Halbach effect may not be a common topic over dinner, but the arrays are appearing in some of the best tech including maglev trains, hoverboards (that don’t ride on rubber wheels), and the particle accelerators they were designed for.

Once aligned, these arrays sculpt a magnetic field. The field can be one-sided, neutralized at one point, and metal filings are used to demonstrate the shape of these fields in a quick video. In the video after the break, a powerful magnetic field is built but when a rare earth magnet is placed in the center, rather than blasting into one of the nearby magnets, it wobbles lazily.

Be careful when working with powerful magnets, they can pinch and crush, but go ahead and build your own levitating flyer or if you came for hoverboards, check out this hoverboard built with gardening tools.

 

Continue reading “Step The Halbach From My Magnets”

Soda Can Art

A can of soda costs about half a dollar, and once you’re done with the sugary syrup, most cans end up in the trash headed for recycling. Some folks re-use them for other purposes, but we’re guessing no one up-cycles them quite like artist [Noah Deledda] does. He turns them into pieces of Soda Can art that sell for anywhere between $2000 to $3000 a pop.

Don’t be fooled by that smashing hit in the GIF. It’s just some trick photography that [Noah] did to impress people. If you looked at the end product without the back story first, you’d think the cans were manipulated in to contorted shapes using some kind of mechanical assistance, at the very least, or probably a purpose-built machine.

But [Noah Deledda] does it with bare hands. This is the bare-metal version of Origami. While on a road trip many years ago, he was bereft of electronic devices to keep him busy. Playing with an empty can of soda, he started denting and squeezing the thin metal in to an abstract shape. That’s when the artist in him realized that he was playing with an exciting new medium. After making some abstract art pieces out of empty cans of a vermillion bovine energy drink, he figured it would look much more awesome if he could remove all the paint from the cans and give them a smooth, polished, natural finish. He made a little machine that rotates the cans so he can strip the paint and bring the cans to a high polish. The technique is simple but requires a lot of patience, practice, time and skill, not to mention that it will cause a lot of pain in the thumb.

If you’ve ever been to Japan and drank a can of Kirin Hyoketsu, you’d notice the un-opened can is smooth, but immediately changes to a pattern of indented diamonds once you open it. That design was created by Kyoro Miura, well-known for the Miura Fold that lets you fold and unfold large sheets of paper in one smooth movement. Like that discarded map in the glove box of the car you’re riding in, while playing with an empty can of soda.

If you want to hone some ambidextrous skills, this would be a good way to do it while on your next road, plane or train trip. Check out the two videos embedded below. In the second one, you can see snapshots of the design process.

Thanks, [Keith O], for this tip.

Continue reading “Soda Can Art”

Make or buy lithium ion battery pack

Comparing Making To Buying A Lithium Ion Battery Pack

At Hackaday we’re all about DIY. However, projects can have many components, and so there’s sometimes a choice between making something or buying it. In this case, [GreatScott!] wondered if it would be cheaper to make or buy a lithium-ion battery pack for his new eBike kit. To find out, he decided to make one.

After some calculations, he found he’d need thirteen 18650 cells in series but decided to double the capacity by connecting another thirteen in parallel. That gave him a 5 Ah capacity battery pack with a nominal voltage of 48.1 V and one capable of supplying a constant current of 40 A. Rather than connect them by soldering the nickel strips, he purchased a kWeld battery spot welder, adding to the cost of the build. He charged his new battery pack using his bench power supply but being concerned about uneven charging of the cells over the battery pack’s lifetime, he added a Battery Management System (BMS). The resulting battery pack powers his eBike motor just fine.

After adding up all the costs, he found it was only a tiny bit cheaper than prices for comparable battery packs on eBay, which were €24.4 per Ah (US$29.5 per Ah). The only way it would be cheaper is if he made multiple packs, spreading out the one-time cost of the battery spot welder. So that means it’s really up to your preference. See his video below to judge for yourself if you’d rather do it the DIY way. And then let us know what you’d do in the comments below.

Continue reading “Comparing Making To Buying A Lithium Ion Battery Pack”

Playing Pong With Micro:bits!

Where would the world be today without Pong, perhaps a lot less fun? For people like [Linker3000] the game is an inspiration toward teaching the next generation of hackers to build and play their own version using Micro:bits as controllers!

Aiming for doing all manner of diligence, [Linker3000] says the code can simply be uploaded to an Arduino — foregoing throwing together a circuit of your own — if you want to jump right into things. For the workshop environment, this setup uses composite video outputs — but this shouldn’t be an issue as most TVs still retain these inputs.

Once built — or sketch uploaded — the Micro:bit paddles can be connected to the ATmega328p and played like an old-school controller, but [Linker3000] has enabled Bluetooth control of the paddles’ A and B buttons via the Bitty app. Additionally — if wires really aren’t your thing and Bluetooth is too new-school for such an old game — a second Micro:bit can control the wired paddle using their built-in radio, provided they’re configured accordingly.

On top of Pong, there are also squash and soccer game modes! Check out the demo after the break.

Continue reading “Playing Pong With Micro:bits!”

How To Put The ‘Pro’ In Prototype

It’s easy to get professional-quality finishes on your prints and prototypes if you take the right steps. In the final installment of his series about building with Bondo, product designer [Eric Strebel] shows us how it’s done no matter what the substrate.

How does he get such a smooth surface? A few key steps make all the difference. First, he always uses a sanding block of some kind, even if he’s just wrapping sandpaper around a tongue depressor. For instance, his phone holder has a round indent on each side. We love that [Eric] made a custom sanding block by making a negative of the indent with—you guessed it—more Bondo and a piece of PVC. The other key is spraying light coats of both primer and paint in focused, sweeping motions to allow the layers to build up.

If you need to get the kind of surface that rivals a baby’s behind, don’t expect to prime once, paint once, and be done with it. You must seek and destroy all imperfections. [Eric] likes to smooth them over with spot putty and then wet sand the piece back to smooth before applying more primer. Then it’s just rinse and repeat with higher grits until satisfied.

There’s more than one way to smooth a print, of course. Just a few weeks ago, our own [Donald Papp] went in-depth on the use of UV resin.

Continue reading “How To Put The ‘Pro’ In Prototype”

An Open-Source Turbomolecular Pump Controller

It’s not every project write-up that opens with a sentence like “I had this TURBOVAC 50 turbomolecular pump laying around…”, but then again not every write-up comes from someone with a lab as stuffed full of goodies as that of [Niklas Fauth]. His pump had an expired controller board, so he’s created an open-source controller of his own centred upon an STM32. Intriguingly he mentions its potential use as “I want to do more stuff with sputtering and Ion implantation in the future“, as one does of course.

So given that probably not many Hackaday readers have a turbomolecular pump lying around but quite a few of you will find the subject interesting, what does this project do? Sadly it’s a little more mundane than the pump itself, since a turbomolecular pump is a highly specialised multi-stage turbine, this is a 3-phase motor controller with analogue speed feedback taken from the voltage across a couple of the motor phases. For this reason he makes the point that it’s a fork of his hoverboard motor controller software, the fruits of which we’ve shown you in the past. There isn’t a cut-out timer should the motor not reach full speed in a safe time, but he provides advice as to where to look in the code should that be necessary.

This is by no means the first turbomolecular pump to make it to these pages, in 2016 we brought you one taking inspiration from a Tesla turbine.