Computer interfaces without keyboards

A group of European scientists have used acoustic sensors to turn wooden tabletops and even three-dimensional objects into a new type of computer interface which may prove useful in healthcare.

The researchers – in Germany, France, Italy, England, Wales and Switzerland – who were brought together by the project, part-funded by the European Commission, admit that mice and keyboards will not be replaced soon.

They say, however, that tangible acoustic interfaces (TAIs) could provide an elegant solution in specific environments such as hospitals where keyboards might harbour bugs.

The researchers on the TAI-CHI (Tangible Acoustic Interfaces for Computer-Human Interaction) project have exploited the excellent propagation of sound waves through solids to turn everyday objects – including 3D objects – into a new kind of computer interface.

By attaching sensors to solid materials, researchers were able to locate exactly and track acoustic vibrations. Tapping on discrete areas of a whiteboard could generate musical notes on a computer. Tracking the sound of a finger scrawling words on a sheet of hardboard could translate, in real time, into handwriting on a computer screen. There is no need for overlays or intrusive devices.

The researchers say that sensing vibrations in a solid and converting them to electrical pulses is the easy bit. Exactly locating the source of that vibration in a solid material is where it gets complicated. The problem is that the complex structures of solids make wave propagation difficult to model. Wood knots in a desktop, for instance, will alter how acoustic vibrations disperse.

The TAI-CHI team investigated four main technologies: Time Delay of Arrival (TDOA); Multi-Sensor Tracking through the Reversal of Dispersion; Time reversal and in-solid acoustic holography.

Dr Ming Yang of the University of Cardiff said: “Time reversal is a beautiful technology. Unlike TDOA, it works with any object and it does not require special materials. Because it needs only a single sensor and a normal computer, it is very simple and cost-effective. One spin-off company from the University of Paris is working on commercial applications for this.”

Other technologies, such as acoustic holography, show great promise but are not ready for commercialisation, the researchers concluded.

CeTT, a Swiss member of the consortium, has put together a TAI-CHI Developer’s Kit, comprising algorithms developed during the project, software and hardware, as a one-stop-shop for application developers looking to build on TAI-CHI breakthroughs.

Other applications include a wireless sensor using Bluetooth technology that Dr Ming Yang would like to develop with commercial partners.

The time-reverse technology is the project’s major breakthrough, according to Dr Ming Yang. “Before, people were only working on easy materials. We have developed it for metal, plastic and board. We have a really interactive interface.”

Further details at ICT Results.

Linda Davidson