We propose a novel sensor interface for detecting notes in the musical audio signals, particularly with reference to polyphonic music of percussive pitched musical instruments. Our sensor interface is able to transform acoustic pressure, caused by a sound wave, into a musical score, that is a symbolic representation of musical notes. We focuses on note events and their main characteristics: the onset (note attack instant) and the pitch (note name). Signal processing techniques based on the Constant-Q Transform (CQT) are used to create a time-frequency representation of the signal. In particular, we propose a supervised classification methods based on Support Vector Machine (SVM) to detect pitch. Instead, our onset detection algorithm exploi...