This paper describes a performer-centric approach to the design, sensor selection, data interpretation, and mapping schema of a sensor-embedded glove called the “alto.glove” that the author uses to extend his performance abilities on violin. The alto.glove is a response to the limitations—both creative and technical—perceived in feature extraction processes that rely on classification. The hardware answers one problem: how to extend violin playing in a minimal yet powerful way; the software answers another: how to create a rich, evolving response that enhances expression in improvisation. The author approaches this problem from the various roles of violinist, hardware technician, programmer, sound designer, composer, and improviser. Importantly, the alto.glove is designed to be cost-effective and relatively easy to build.