Using Mid-Air Haptics to Guide Mid-Air Interactions

When users interact with mid-air gesture-based interfaces, it is not always clear what interactions are available, or how they might be executed. Mid-air interfaces offer no tactile affordances, pushing systems to rely on other modalities (e.g. visual) to guide users regarding how to interact with the interface. However, these alternative modalities are not always appropriate or feasible (e.g. eyes-free interactions), meaning that they are not easy to learn from touch alone. Despite the possibility of conveying contactless haptic information in mid-air through ultrasound phased arrays, this technology has been limited to providing feedback on user interactions. In this paper, we explore the feasibility of using mid-air haptics to guide gestures in mid-air. Specifically, we present approaches to guide the user's hand in cardinal directions, execute a hand gesture and navigate a 2D mid-air plane, which we tested with 27 participants. After, reporting encouraging results which suggest good accuracy and relatively low workload, we reflect on the feasibility and challenges of using haptic guidance mechanisms in mid-air.