Brighton Science Festival

Space Pianos and Invisible Shapes

Researchers from University of Sussex have been investigating how to manipulate ultrasound to create tangible objects made of air. They are bringing some of their newest prototypes to Bright Sparks.

What exactly will you be doing?
Imagine two sound waves coming from opposite directions – where they meet will either cancel out or reinforce each other, creating valleys and mountains: a ‘net of sound’ that can be used to trap objects in mid-air. Timing ultrasound waves very precisely, we can create invisible objects in thin air… that can be touched. They can also levitate objects and move them at a distance, like in sci-fi and fantasy movies.

We will demonstrate how to shape ultrasound fields and use them to create 3D displays made of floating objects, how to create invisible objects that you can feel in mid-air (like in the Iron Man films), how to levitate objects against gravity (much like tractor beams in Star Trek), and how use specially designed blocks (a little like LEGO bricks) to control the direction of sound. We will be demonstrating different demos from our research, including keyboards made of electrical sparks and 3D displays made of bubbles and fog.
How does it work?
A simple way to make an object fly might be to blow air at it from below: imagine a piece of paper or a soap bubble. This could work for a small object, but to make something larger fly, lots of team work would be needed. It turns out in fact that the best way is not to puff simultaneously, as some puffs will cancel each other out or combine to blow the object away, but to blow with perfect timing, so that the pressure around the object is the same. Like in a well-conducted orchestra.

We exploit this idea using ultrasound, which is pressure, but at frequencies we can’t hear. By using many small ultrasound speakers, points of high and low pressure can be created at chosen locations in mid-air, and these together give the feeling of touching invisible 3D objects. Like in a “Connect the Dots” game. An invisible cup/bottle shape can then be used to hold small objects, essentially making them levitate without any visible means of support.

As the number of ultrasound speakers increases, so does the cost of the device…and this led us to engineer new materials that can shape sound. These meta-materials, which we 3D print in the form of much cheaper LEGO-like ‘bricks’, create similar high and low pressure points naturally, when placed in front of a speaker. Using these bricks in holographic patterns can create even complex 3D shapes made of sound, like alphabet letters.

Why are you doing it?
Touch is a fundamental human sense that plays a rich and emotive role in our daily interactions with the physical world. However, our devices are increasingly becoming flat and inaccessible to our sense of touch – keyboards are becoming screens, voice control is becoming ever more integrated and gestural recognition and control is available in more and more applications.

A key goal of our work is to bring the sense of touch back to these devices; by using haptics and levitation we hope to create displays that physically change shape, so they are as 3D to our hands, as they are to our eyes. We also aim to re-inject the sense of touch into ‘natural’ interaction systems, such as gesture control, ultimately creating a more human way of using our devices.

This event is part of Bright Sparks Saturday and Sunday 2017.