The design of new instruments and controllers for performing live computer music is an exciting field of research that can lead to truly new music-making paradigms. The ever-increasing availability of sensing technologies that enable virtually any kind of physical gesture to be detected and tracked has indeed sprouted a wealth of experimental instruments and controllers with which to explore new creative possibilities. However, the design of these new controllers is often approached from an essentially technical point of view in which the novelty of the sensing technologies deployed overshadows the attainable musical results. Although new instruments are not constrained to the physical restrictions of traditional ones, an integrated approach in which the instrument is designed as a whole and not as a combination of arbitrary input and output devices can lead to the creation of more rewarding and more musical instruments. This article describes an attempt at an integrated conception, called F@ust Music On-Line (FMOL), which is a simple mouse-controlled instrument that has been used on the Internet by hundreds of musicians during the past four years. FMOL has been created with the complementary goals of introducing the practice of experimental electronic music to newcomers while trying to remain attractive to more advanced electronic musicians. It has been used by musicians of diverse skills for the collective composition of the music of two important shows, including one opera of the Catalan theatre group La Fura dels Baus. It is also being played in live concerts.

FMOL 1.0 was developed with the financial support of the Sociedad General de Autores y Editores (SGAE).