Martin Kaltenbrunner is a Human Computer Interaction Designer, currently finalizing his Ph.D. at the Pompeu Fabra University in Barcelona, Spain. Recently he has been mainly working on the interaction design of the reacTable - a tangible modular synthesizer based on a multi-touch surface. He is author of the open source tangible interaction framework reacTIVision and the related TUIO protocol, which has been widely adopted for open source multi-touch applications. He is co-founder of reactable systems SL, dedicated to the development of novel HCI concepts and products, while he is teaching classes and workshops on tangible interaction at the Kunstuniversität Linz and at the UCP Porto.

http://modin.yuri.at/

reacTIVision is an open source, cross-platform computer vision tool for the fast and robust tracking of fiducial markers attached onto physical objects, as well as for multi-touch finger tracking.

http://reactivision.sourceforge.net/

TUIO is an open framework that defines a common protocol and API for tangible multi-touch surfaces. The TUIO protocol allows the transmission of an abstract description of interactive surfaces, including touch events and tangible object states. There exists a growing number of TUIO enabled tracker applications and TUIO client libraries for various programming environments, as well as applications that support the protocol. This combination of TUIO trackers, protocol and client implementations allows the rapid development of table based tangible multitouch interfaces.

http://www.tuio.org/

The reactable is a collaborative electronic music instrument with a tabletop tangible multi-touch interface. Several simultaneous performers share complete control over the instrument by moving and rotating physical objects on a luminous round table surface. By moving and relating these objects, representing components of a classic modular synthesizer, users can create complex and dynamic sonic topologies, with generators, filters and modulators, in a kind of tangible modular synthesizer or graspable flow-controlled programming language.

The instrument has been developed by a team of digital luthiers, the two Austrian researchers Martin Kaltenbrunner and G%uuml;nter Geiger and their Spanish colleagues Marcos Alonso and Sergi Jord, working at the Music Technology Group within the Pompeu Fabra University in Barcelona. This multidisciplinary team of researchers, musicians and designers  has been awarded with various international prizes such as the Prix Ars Electronica Golden Nica, two D&AD Yellow Pencils and the prize if the city of Barcelona.

After its overwhelming success on Youtube and since the Icelandic singer Björk has incorporated the instrument during her last Volta world tour, the reacTable has become widely known to the general public.

http://www.reactable.com/