RapTapBath
Tomoyuki Sumida, Shigeyuki Hirai, Daiki Ito, Ryosuke Kawakatsu · 2017
We present RapTapBath: a human-computer interface system that converts an existing bathtub into a controller that recognizes hand-tapped tones and patterns on a bathtub's edge. This system utilizes embedded piezoelectric sensors in the bathtub's edge to analyze acoustic signals of tapped sounds, and projects a menu on the tub's edge using a projector installed above the tub. Tap locations are detected by measuring differences of signal propagation times using the piezoelectric sensors. Tap tones are identified by spectrum patterns using non-negative matrix factorization. Tap patterns are detected via tapping rates, whose probability calculations are measured over a fixed duration. This paper describes the tapping user interface's (UI) events and their specific detection methods and signal processing techniques. We also present an experimental performance evaluation. We also propose effective applications for spending bath time using this system. Finally, we describe the limitations of current tap UI events and the implications of interaction designs of RapTapBath.