FlatTouch - (CHI 16)

Smartwatches are emerging device category that feature highly limited input and display surfaces. We explore how touch contact areas, such as lines generated by flat fingers, can be used to increase input expressivity in these diminutive systems in three ways. Firstly, we present four design themes that emerged from an ideation workshop in which five designers proposed concepts for smartwatch touch area interaction. Secondly, we describe a sensor unit and study that captured user performance with 31 area touches and contrasted this against standard targeting performance. Finally, we describe three demonstration applications that instantiate ideas from the workshop and deploy the most reliably and rapidly produced area touches. We report generally positive user reactions to these demonstrators: the area touch interactions were perceived as quick, convenient and easy to learn and remember. Together this work characterizes how designers can use area touches in watch UIs, which area touches are most appropriate and how users respond to this interaction style.