A Mobius Strip Track For Superconductor Levitation

March 23, 2021 by Lewin Day 13 Comments

Superconductors are interesting things, though we don’t really rely on them for much in our day to day lives. They’d be supremely useful, if only they didn’t need to be so darned cold. While the boffins toil away in the lab on that problem however, there’s still some fun to be had, as demonstrated by the Möbius Strip levitation track at Ithaca College. (Video, embedded below.)

The rig takes advantage of the fact that superconductors can levitate over magnets, and vice versa. Under certain conditions, the superconductor can even lock into position over a magnet, due to flux pinning, wherein flux “tubes” from the magnet’s field penetrate a superconductor and are pinned in place by currents in the superconductor. It’s an awe-inpsiring effect, with the superconducting material appearing to magically float at a locked height above the magnetic surface, quite distinct from traditional magnetic levitation.

Construction of the track wasn’t straightforward. Early attempts at producing a Möbius Strip twisted through 540 degrees were unsuccessful in steel. The team then switched tack, using a flexible plastic which was much more pliable. This was then covered in neodymium magnets to create the necessary field, and the resulting visual effect is one of a silver-bricked magnetic road.

It’s a great display, and one that quite intuitively demonstrates the concepts of both a Möbius Strip and superconducting levitation. If room-temperature semiconductors become a real thing, there’s every possibility this could become an always-on installation. It’s also the trick behind one of the coolest hoverboards we’ve ever seen. Video after the break.

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Hackaday Links: November 22, 2020

November 22, 2020 by Dan Maloney 6 Comments

Remember DSRC? If the initialism doesn’t ring a bell, don’t worry — Dedicated Short-Range Communications, a radio service intended to let cars in traffic talk to each other, never really caught on. Back in 1999, when the Federal Communications Commission set aside 75 MHz of spectrum in the 5.9-GHz band, it probably seemed like a good idea — after all, the flying cars of the future would surely need a way to communicate with each other. Only about 15,000 vehicles in the US have DSRC, and so the FCC decided to snatch back the whole 75-MHz slice and reallocate it. The lower 45 MHz will be tacked onto the existing unlicensed 5.8-GHz band where WiFi now lives, providing interesting opportunities in wireless networking. Fans of chatty cars need not fret, though — the upper 30 MHz block is being reallocated to a different Intelligent Transportation System Service called C-V2X, for Cellular Vehicle to Everything, which by its name alone is far cooler and therefore more likely to succeed.

NASA keeps dropping cool teasers of the Mars 2020 mission as the package containing the Perseverance rover hurtles across space on its way to a February rendezvous with the Red Planet. The latest: you can listen to the faint sounds the rover is making as it gets ready for its date with destiny. While we’ve heard sounds from Mars before — the InSight lander used its seismometer to record the Martian wind — Perseverance is the first Mars rover equipped with actual microphones. It’s pretty neat to hear the faint whirring of the rover’s thermal management system pump doing its thing in interplanetary space, and even cooler to think that we’ll soon hear what it sounds like to land on Mars.

Speaking of space, back at the beginning of 2020 — you know, a couple of million years ago — we kicked off the Hack Chat series by talking with Alberto Caballero about his “Habitable Exoplanets” project, a crowd-sourced search for “Earth 2.0”. We found it fascinating that amateur astronomers using off-the-shelf gear could detect the subtle signs of planets orbiting stars half a galaxy away. We’ve kept in touch with Alberto since then, and he recently tipped us off to his new SETI Project. Following the citizen-science model of the Habitable Exoplanets project, Alberto is looking to recruit amateur radio astronomers willing to turn their antennas in the direction of stars similar to the Sun, where it just might be possible for intelligent life to have formed. Check out the PDF summary of the project which includes the modest technical requirements for getting in on the SETI action.

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Eye-Catching And Crumb-Suspending

September 10, 2020 by Brian McEvoy 5 Comments

Printed circuit boards used to be green or tan, and invariably hidden. Now, they can be artful, structural, and like electronic convention badges, they are the entire project. In this vein, we find Open LEV, a horseshoe-shaped desktop bauble bristling with analog circuitry supporting an acoustic levitator. [John Loefler] is a mechanical engineer manager at a college 3D printing lab in Florida, so of course, he needs to have the nerdiest stuff on his workspace. Instead of resorting to a microcontroller, he filled out a parts list with analog components. We have to assume that the rest of his time went into making his PCB show-room ready. Parts of the silkscreen layer are functional too. If you look closely at where the ultrasonic transducers (silver cylinders) connect, there are depth gauges to aid positioning. Now that’s clever.

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Behold A 3D Display, Thanks To A Speeding Foam Ball

November 19, 2019 by Donald Papp 15 Comments

We’ve seen 3D image projection tried in a variety of different ways, but this is a new one to us. This volumetric display by Interact Lab of the University of Sussex creates a 3D image by projecting light onto a tiny foam ball, which zips around in the air fast enough to create a persistence of vision effect. (Video, embedded below.) How is this achieved? With a large array of ultrasonic transducers, performing what researchers call ‘acoustic trapping’.

This is the same principle behind acoustic levitation devices which demonstrate how lightweight objects (like tiny polystyrene foam balls) can be made to defy gravity. But this 3D display is capable of not only moving the object in 3D space, but doing so at a high enough speed and with enough control to produce a persistence of vision effect. The abstract for their (as yet unreleased) paper claims the trapped ball can be moved at speeds of up to several meters per second.

It has a few other tricks up its sleeve, too. The array is capable of simultaneously creating sounds as well as providing a limited form of tactile feedback by letting a user touch areas of high and low air pressure created by the transducers. These areas can’t be the same ones being occupied by the speeding ball, of course, but it’s a neat trick. Check out the video below for a demonstration.
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Both Explanation And Build For This Artwork Are Beautiful

January 15, 2019 by Brian McEvoy 19 Comments

Sometimes you encounter projects that defy description, as is the case with this one. So perhaps it’s best to start with what this project is NOT. It is not a sphere. It is not a perpetual energy device. It has neither a sloppy build nor a slapdash video. This IS a motorized rhombicuboctahedron that is a well-explained with high-quality parts and loving attention to detail by [Wolfram Glatthar]. At its heart is an exercise in building a moving device with the barest minimum of friction. Without no grinding in the mechanism, the electronics will probably wear out first. Low friction also means low power consumption, and an hour of sunlight can run the device for two-and-a-half days. Take a look at the video below the break.

Along the sides are a balancing ring with threaded screw sockets and the load-bearing magnets which suspend the bulk of the rhombicuboctahedron using repulsion. Everything is stabilized by a ceramic sphere touching a sapphire glass plate for a single point of contact between some seriously tough materials. The clear sapphire furthers the illusion that everything is floating, but genuine magnetic suspension would require much more power.

Acoustic levitation cannot be forgotten as another powered source of floating or you can cheat and use strobe light trickery.

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72 Tranducers For Acoustic Levitation

November 28, 2018 by Lewin Day 9 Comments

Levitation has a way of arousing curiousity and wonder wherever it appears. There’s a multitude of ways to do it, each with their own strengths and weaknesses and ideal use cases. [Julius Kramer] tried his hand at acoustic levitation, and decided to share his build.

The build relies on an astounding number of ultrasonic transducers – 72, in fact. The device operates at 40 kHz to be well above the human range of hearing. 36 each are placed in the top and bottom shells of the device’s 3D printed chassis. Through careful construction, the transducers are placed an integer multiple of half the wavelength apart. This allows the device to create a standing wave, with several low-energy nodes in which small objects can be levitated. In this case, [Julius] uses small scraps of styrofoam, but notes that water droplets can also be used if one is careful to avoid spilling any on the electronics.

The transducers are energised with a square wave generated by an Arduino Nano. This allows the possibility of the frequency and phase of the wave to be altered, which can help tune the device and allow some movement in the vertical axis. Unfortunately, movement in the other axes isn’t possible as the transducers appear to be connected in parallel. However, this could be a good upgrade in a later revision.

This project shows that a device relying on incredibly precise measurement and control can now be constructed at home with a 3D printer and some off the shelf electronics.

Now that you’ve whet your whistle, perhaps you’d like to tackle laser levitation?

[Thanks to Baldpower for the tip!]

Star Wars Speeder’s Finishing Touch: Mirrors

November 8, 2017 by Donald Papp 19 Comments

[Super 73] make electric scooters, and they made some Star Wars Speeder Bikes with a twist for Halloween; adding some mirrored panels around the bottoms of the bikes made for a decent visual effect that requires no upkeep or fancy workings. Having amazed everyone with the bikes, they followed them up with a video of the build process.

The speeders are shells built around their Super 73 electric scooter, with bases of what looks like MDF sitting on anchor points. Onto the base platforms goes cardboard and expanding foam to create the correct shapes, which are then sanded then coated in fiberglass and bondo. Then it’s time for paint, weathering, and all the assorted bits and pieces needed to make the speeders as screen-accurate as possible. The real finishing touch are the mirrored panels to conceal the wheels and create a levitation illusion. As long as the mirrors are angled so that they reflect the pavement when viewed by a pedestrian, it works fairly well.

Top it off with costumes and a ride around town (with plenty of cameras of course, they naturally wanted to grab some eyeballs) and we have to say, the end result looks nifty. Both the showcase and making-of videos are embedded below.

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