Deep Pedal reveals the deep secrets of expressive piano playing through analysis and modelling of the pedalling gestures and techniques. Informed by piano acoustics and music theory, it deeply elaborates on the studies in the sensor and audio domains, applying signal processing and deep learning techniques to better event detection. Main features include: 1) Measurement, recognition and visualisation of piano pedalling gestures and techniques;​ 2) Exploiting musically motivated audio features for legato-pedal onset detection; 3) Employing deep learning to identify sustain-pedal segments in piano music; 4) Facilitating the development of piano transcription and pedagogy applications.