In this work, we present Tasbi, a multisensory haptic wristband capable of delivering squeeze and vibrotactile feedback. The device features a novel mechanism for generating evenly distributed and purely normal squeeze forces around the wrist. Our approach ensures that Tasbi’s six radially spaced vibrotactors maintain position and exhibit consistent skin coupling. In addition to experimental device characterization, we present early explorations into Tasbi’s utility as a sensory substitution device for hand interactions, employing squeeze, vibration, and pseudo-haptic effects to render a highly believable virtual button.

The onset of interaction is triggered through vibrotactile cues rendered when the user’s avatar finger collides with the surface of the button. As the user presses the button inward, proportional squeeze is delivered through the band to convey stiffness. By changing the rate of squeeze, the perceived stiffness can be altered. A second vibrotactile stimulus is rendered when the button is fully depressed. Similar to a “god-object”, the avatar hand is projected onto the button surface so that it never appears to penetrate. The illusion of different stiffness levels is also affected by changing the control-display (C/D) ratio between the user’s real and avatar hands, such that a stiffer button requires more real-world displacement. Within the haptics community, this visual effect falls under “pseudo-haptics”. Users commented that the combination of vibrotactile, squeeze, and C/D stimuli created a highly intuitive and believable effect.

https://research.fb.com/wp-content/uploads/2019/07/Tasbi-Multisensory-Squeeze-and-Vibrotactile-Wrist-Haptics-for-Augmented-and-Virtual-Reality.pdf