Performing music with a computer and loudspeakers represents always a challenge. The lack of a traditional instrument requires the performer to study idiomatic strategies by which musicianship becomes apparent. On the other hand, the audience needs to decode those strategies, so to achieve an understanding and appreciation of the music being played. The issue is particularly relevant to the performance of music that results from the mediation between biological signals of the human body and physical performance. The present article tackles this concern by demonstrating a new model of musical performance; what I define biophysical music. This is music generated and played in real time by amplifying and processing the acoustic sound of a performer’s muscle contractions. The model relies on an original and open source technology made of custom biosensors and a related software framework. The succesfull application of these tools is discussed in the practical context of a solo piece for sensors, laptop and loudspeakers. Eventually, the compositional strategies that characterize the piece are discussed along with a systematic description of the relevant mapping techniques and their sonic outcome.