Using Acoustic Levitation for Applications Going Way Beyond Novelty

We’ve all seen acoustic levitation, it’s one of the scientific novelties of our age and a regular on the circuit of really impressive physical demonstrations of science to the public. The sight of arrays of ultrasonic speakers causing small objects and beads of liquid to float in mid-air without any suspension is magical, captivating people of all ages. Thus a lecture at Hackaday Belgrade on the subject from Asier Marzo, a research scientist with a speciality in the field of ultrasonics at the UK’s University of Bristol, was a particularly fascinating and informative one.

He started by explaining acoustic levitation as a concept, and its mechanism. As an idea it’s one with a long history, he tells us that hundreds of years ago people tried mass ranks of the loudest musical instruments at their disposal to move rocks, all to no avail. The array of musicians of yore lacked the ability to control their individual phase, and of course their combined output would have balked at a pea-sized piece of gravel, let alone a boulder.

Explaining the standing wave produced by an ultrasonic array.
Explaining the standing wave produced by an ultrasonic array.

The Power of Standing Waves

Given that we can now create standing waves between phased arrays of ultrasonic speakers, he explained the mechanism that allows the levitation. The standing wave creates patterns of high intensity and “quiet” low intensity sound, and the object nestles in one of these quiet areas. There is thus a size limit dictated by the wavelength of the sound in question, which for the ultrasound he’s using is in the order of a few millimetres.

Having explained how it all works, we were then taken into the fields in which it finds an application. This was particularly interesting, because it’s the side we never see in the for-the-kids demos where it’s all about “Look, we can make the water droplet float!”. The number of fields that can find a use for it was a surprise, and formed the next phase of the talk.

Real World Uses for Acoustic Levitation

The first example given was in the field of spectroscopy, when reflecting light from a droplet of liquid on a substrate a certain amount of the reflected light comes from the substrate. If the sample is levitated, all the reflection comes from it and nothing else. Microgravity experiments are another interesting application, where it is possible to replicate some of the work that has previously required  the environment of a space craft such as the International Space Station. This was a particularly unexpected twist.

Explaining the standing wave produced by an ultrasonic array.
Manipulating a solid particle with a wearable array.

The technique can be used for tiny particles in a liquid medium with a much higher frequency — a demonstration involves moving a single blood cell in a pattern. But Asier has more tricks up his sleeve. This technique can be used in human interactions with computers and with the real world. We saw a display in which the pixels were small plastic balls suspended in a grid, they could even be flipped in colour by being rotated under an electric field. A successive display used the balls not in a grid but as a point cloud in a graph, proving that rasters are not the only means of conveying information. Finally we saw the arrays applied to wearable devices, a handheld tractor beam, and a set of standing wave tweezers. He gave the example of picking up an SMD component, something that we can see would be invaluable.

Levitation is Within Our Grasp

The good news for us is that this is a piece of cutting-edge science that is accessible to us at our level too. He’s made a selection of designs available online through the Acoustic Levitator site. There is an ultrasonic array, an acoustic levitator, and an acoustic tractor beam, and the components are such run-of-the-mill parts as Arduinos and motor driver boards. Even schoolchildren building them from kits, with an experimenter using one for Schlieren photography of the acoustic field. Finally we’re shown Ultraino, an ambitious project providing software and driver hardware for large arrays in which every transducer is individually driven, before a tantalising look at future work in fluid ultrasonics and the promise of an ultrasonic audio speaker project.

Hackaday covers a huge array of projects and topics from all corners of our community. Each one is exciting in its own way, from a simple-looking Arduino project that encapsulates a cool hack to a multi-year labour of love. It’s not often though that we can say we’ve seen a genuinely cutting-edge piece of science, while simultaneously having it explained in terms we understand and being given an accessible version that we can experiment with ourselves. We are really looking forward to the projects that will come from this direction, as acoustic levitation becomes yet another known quantity in the hardware hacker’s armoury.

Hackaday Belgrade: Sophi Kravitz’s Blimp Army

Building things that fly is hard. The constraints on small, battery powered, radio-operated gear already presents a challenge, but adding weight, balance, and aerodynamic constraints takes it to a whole new level. Sophi Kravitz rises to the occasion and discusses each challenge of building a blimp from start to finish in her presentation at the 2018 Hackaday Belgrade conference.

One of the pleasures of writing for Hackaday comes through the incredible array of talent and experience to be found among our colleagues. We all do our own work, but one is humbled by that which flows from the benches of those one works alongside. Just such a project is the Remote Control Mini Blimp from our colleague Sophi Kravitz. It’s a game involving an obstacle course and a set of remote-controlled blimps. The challenges in such an endeavour have been pushing the limits of what is possible with off-the-shelf components. Continue reading “Hackaday Belgrade: Sophi Kravitz’s Blimp Army”

Hackaday Belgrade: Luka Mustafa on Exploiting IoT Niches

Ecology is a strange discipline. At its most basic, it’s the study of how living things interact with their environment. It doesn’t so much seek to explain how life works, but rather how lives work together. A guiding principle of ecology is that life finds a way to exploit niches, subregions within the larger world with a particular mix of resources and challenges. It’s actually all quite fascinating.

But what does ecology have to do with Luka Mustafa’s talk at the 2018 Hackaday Belgrade Conference? Everything, as it turns out, and not just because Luka and his colleagues put IoT tools on animals and in their environments to measure and monitor them. It’s also that Luka has found a fascinating niche of his own to exploit, one on the edge of technology and ecology. As CEO of Institute IRNAS, a non-profit technology development group in Slovenia, Luka has leveraged his MEng degree, background in ham radio, and interest in LoRaWAN and other wide-area radio networks to explore ecological niches in ways that would have been unthinkable even 10 years ago, let alone in the days when animal tracking was limited by bulky radio collars.

Continue reading “Hackaday Belgrade: Luka Mustafa on Exploiting IoT Niches”

Belgrade Badge Hacks

We’re still coming off the Hackaday Belgrade conference right now. If you were there, you know it was the greatest hardware conference ever. If you weren’t there, you missed out. Sorry. (Make sure you get in on the Hackaday Superconference in November.)

One of the many highlights of the Belgrade conference was, of course, the badge. The 2018 Hackaday Belgrade Badge is a masterpiece of hardware with a 55-key keyboard, RGB TFT LED, speaker, and a BASIC interpreter.

This badge is a masterpiece of electronic design by Voja Antonic. Just to take one small example from the design, check out the placement of the buttons. Think the slightly rotated buttons that make up the keyboard is only a stylistic choice? It’s not; by carefully rotating each button, the legs of each switch can fit in between each other. It’s brilliant.

Starting hardware this good, adding amazing software by Jaromir Sukuba to bring it to life, and distributing a badge to each hacker through the door is the perfect recipe for some amazing hacks. What were the best badge hacking tricks we saw at the 2018 Hackaday Belgrade conference? Check out the video of the badge hacking ceremonies and then join us below for a few of our favorites.

Continue reading “Belgrade Badge Hacks”

Rachel Wong Keynote: Growing Eyeballs in the Lab and Building Wearables that Enhance Experience

The keynote speaker at the Hackaday Belgrade conference was Rachel “Konichiwakitty” Wong presenting Jack of All Trades, Master of One. Her story is one that will be very familiar to anyone in the Hackaday community. A high achiever in her field of study, Rachel has learned the joy of limiting how much energy she allows herself to expend on work, rounding out her life with recreation in other fascinating areas.

There are two things Rachel is really passionate about in life. In her professional life she is working on her PhD as a stem cell researcher studying blindness and trying to understand the causes of genetic blindness. In her personal life she is exploring wearable technology in a way that makes sense to her and breaks out of what is often seen in practice these days.

Continue reading “Rachel Wong Keynote: Growing Eyeballs in the Lab and Building Wearables that Enhance Experience”

A Wild Hackaday Belgrade Confirms Status as One of World’s Greatest Hardware Cons

Hackers, Designers, and Engineers flooded into Dom Omladine on Saturday for what can only be described as an epic celebration of hardware culture. This is the second time Hackaday has organized a huge conference in Belgrade, and lightning really did strike twice.

A Gathering of New Friends and Old

We got things started off with a meetup the night before the conference. The first Hackaday Belgrade was held in 2016 and we didn’t reserve a bar on Friday night — we ended up taking over one just through sheer numbers. This year we called ahead for a large outdoor space, then made good use of it.

Everyone was giddy with anticipation of the next day to come. There is always a sizzling energy of meeting up in real life. Most of this group hangs out on, but only some of them have met in person. Add to that the reunions of those who became friends at the previous Hackaday Belgrade and at other cons around Europe and you have the feeling of coming home. These really are your people.

Yes, a Conference. But the Cool Kind

Hackaday conferences are more than just parties… they’re conferences. If you approach it the right way you can get your employer on board with you attending because you’re going to meet incredible people, learn lots of stuff, and come back excited to take on the Universe. Actually, bring your boss along for the ride too!

This year we had thirteen incredible talks. As is our practice, we started off with a super-technical talk as Rachel Wong (aka @konichiwakitty) discussed her Ph.D research which involves growing eye tissue in the lab. But like all incredibly brilliant minds, she has a creative outlet which she also covered as part of her Keynote address. Rachel has a passion for building wearables that are reaching for the future by embracing things we really do need in our garments and gear.

From drone monitoring networks to robot soldering machines, and concepts for designing meaningful hardware to using code to automate tedious PCB layout, there was plenty in these talks for everyone.

I really enjoyed Elliot Williams’ talk on Logic Noise for his live demos using simple logic chips to build up complex music. Marcel van Kervinck took us on a journey of TTL computer design. And Sophi Kravitz’s talk on building non-rigid airships had at least two people at the con get inspired and spin their own blimp design during the conference! There was a live-feed of the talks so keep your eye on Hackaday as we pull those out to be featured individually.

Some of the demo hardware: Acoustic levitation for lab work

The workshops were standing room only as people who weren’t able to grab a ticket audited the course. We had three hands-on session that built wearable circuitry, brough art to PCB design, and dove into the world of FPGAs.

Welcome, Here’s Your Neck-Mounted Retro Computer

Everyone through the door received a custom electronic badge to hack on during Hackaday Belgrade. Voja Antonic designed the hardware and oversaw the manufacture. We had excellent yield which is great because we had nearly (if not more than) 100% attendance at the conference. We ended the day with just 5 badges to spare!

Hackaday Belgrade badge and user guide put to use

These handheld computers are truly hot! The badges each have 55 really clicky keys. With at least 350 people in the room, that’s approaching 20k momentary push switches and at one point, a brief “silence” fell and all that could be heard were clicking buttons. That and we asked everyone to play the Mario Overworld tune at the same time as hundreds of badges rose in a glorious chorus. There’s also a 16-page user manual to go along with them which included sample code to get started.

Hacking went on throughout the day but as the talk session wrapped up we transformed the hall into a Hacker Village. Tables were brought in and immediately filled. Live music filled the room as Bogdan Rosu and Richard Hogben each played IDM sets. If you’ve been watching Hackaday videos you’ve heard their work and their performances this night were epic.

There was food, there was beer, and there were the tools of our lifestyle; laptops, programmers, jumper wires, blinky add-ons, and the excitement that goes along with all of them. The badge hacking presentations began at midnight and the place was still alive with excitement. It is truly great to see how supportive our community is of exploring hardware and trying things out. Publish your badge hacks and stories from the conference on as we’ll be featuring those in the coming days and want to make sure we have all the juicy details.

Why Belgrade?

Keep your eye on Hackaday as there is much more coverage to come on this wonderful event. Many have asked: “Why Belgrade?”. It’s a fantastic city and the engineering community in the area is passionate about getting together to learn and share ideas. This includes the Supplyframe engineers who live in Belgrade and did the heavy lifting to organize and staff Hackaday Belgrade. You all did an amazing job and everyone at the con owes you a debt of gratitude, thank you so much! We also want to thank Supplyframe and SevenBridges, our sponsors for the event.

To all who attended, it wouldn’t have happened without you! I can speak for everyone on the Hackaday crew in saying the culture we share is energizing, encouraging, and humbling. It’s exactly the kind of recharge everyone looks for to keep life interesting! We’ll see you at the next one. Now over the next five months we have our sights set on the Hackaday Superconference. See you there!

Hackaday Belgrade is On: Join LiveStream and Chat!

Good morning Hackaday universe! Hackaday Belgrade 2018 has just started, and we’re knee-deep in sharing, explaining, and generally celebrating our craft. But just because you’re not here doesn’t mean that you shouldn’t take part.

Come join us!