Exploring Recognition Accuracy of Vibrotactile Stimuli in Sternoclavicular Area

Growing popularity of wearable haptic devices encouraged researchers to implement on-body interfaces that appropriate different form factors and interaction techniques. Among vibrotactile wearable interfaces, neck-worn devices gathered limited attention in HCI. While the ``necklace area'' offers wide opportunities for subtle haptic interaction, we lack knowledge of its tactile acuity to design interactive systems effectively. In this work, we present a prototype of HaptiNecklace - a vibrotactile necklace designed to study tactile acuity of sternoclavicular area. In the experimental study with N=19 participants, we compared recognition accuracy and cognitive load between different numbers of vibrotactile motors attached to the prototype in two scenarios -- static and mobile. The results show that directional patterns ensure better recognition than single-point vibrations in both mobile and static context. Moreover, introducing mobile scenario does not influence recognition accuracy but highly increases cognitive load. In this work, we provide practical hints to designing vibrotactile necklaces.