BathDrum2: Percussion Instruments on a Bathtub Edge with Low-Latency Tap Tone Identification

In order to create a smart bathroom with entertainment features, we propose a playable system that can identify several tap tones on the top of a bathtub edge from differences in hand posture. BathDrum2 is a specific implementation of this system; it utilizes nonnegative matrix factorization (NMF), a kind of machine learning technique, for low-latency tap tone identification and for playing assigned percussion sounds. This paper describes the system design and tap tone identifier with its signal processing and NMF. The performance evaluation of the current BathDrum2 implementation is also described.