This paper describes the "Soundbeam MIDI (Musical Instrument Digital Interface) Controller," which allows even those students who have severe physical disabilities to create interesting aural and musical effects. Soundbeam works by emitting an invisible beam of high frequency sound inaudible to human ears. Even very slight interruptions of and movements within the beam change digital data about the beam's speed and direction. These data can be interpreted by a wide range of electronic musical instruments. The paper notes that this technology is being used in more than 1,000 special education and adult centers in over 20 countries and describes the development of the Soundbeam Project as a partnership between professionals in special education, music composition, electronics, and psychology. The paper explains the operation and performance of the equipment as well as a continuum of possible applications, ranging from the basics of cause-and-effect effect work and "sound therapy" to more ambitious creative/performance applications. Uses of the technology are seen as developing skills such as aesthetic awareness, imagination, listening skills, motor planning skills, memory skills, language skills, and social skills. (Contains 33 references.) (DB)