Reunanen, M.Palovuori, K.Ilmonen, T.Mäkelä, W.Erik Kjems and Roland Blach2014-01-272014-01-272005978-3-905674-06-41727-530Xhttps://doi.org/10.2312/EGVE/IPT_EGVE2005/051-058In this paper we present Näprä, a novel tracking device suitable for fine motor interaction. The motivation for building the device was the need to track users' fingertips in an immersive free-hand drawing environment. Such tracking offers significant benefits for fine-grained artwork. Out of the numerous tracking methods ultrasound was chosen because of its affordability and low computational requirements. The design and implementation of both the hardware and software are discussed in detail in their respective sections. The device was evaluated in practice by two user tests, the first involving ten professional artists and the latter seven ordinary users. The results obtained in the tests are presented to reader as well as some directions for future work.Categories and Subject Descriptors (according to ACM CCS): H.5.2 [User Interfaces]: Input devices and strategies H.5.1 [Multimedia Information Systems]: Artificial, augmented, and virtual realities J.5 [Arts and Humanities]: Fine arts