Development of vibrotactile cradle for smart cell-phone providing spatial and directional cues

In this paper, we applied famous sensory illusions to generate spatial and directional vibrotactile cues using a vibrotactile cradle for the smart cell-phone. A grooved and slim design is applied to the contact side of the cradle for comfortable gripping, and the contact part consists of twelve vibrotactile areas which can operate independently. To maintain isolation among vibrotactile actuators, the surface of the cover is specially designed to absorb propagating vibration over the surface. The cradle's backside consists of twelve linear resonant actuators, a soft covering intersections and supporting area for actuators. For an evaluation of the developed device, two experiments were conducted to test whether directional information and spatial information according to visual data can be successfully displayed by the developed device. As a result, spatial and directional information is useful for displaying intuitive information for smart cell-phone application with the cradle.