Playing the dance. Erkki Kurenniemi's video camera organ

Erkki Kurenniemi is a key name in the history of electronic music. He founded the electronic music studio for the Department of Musicology at the University of Helsinki in the early 1960s. Kurenniemi built several electronic instruments and one of his most ambitious project was the video synthesizer DIMI-O (1970-1971) that converts movements recorded by a video camera into instaneous music compositions.

According to Wikipedia, "Kurenniemi created the first commercially manufactured and marketed microcomputer in 1973,two years before the American MITS Altair 8800".