VHP: Vibrotactile Haptics Platform for On-body Applications

ABSTRACT Wearable vibrotactile devices have many potential applications, including sensory substitution for accessibility and notifications. Currently, vibrotactile experimentation is done using large lab setups. However, most practical applications require standalone on-body devices and integration into small form factors. Such integration is time-consuming and requires expertise. With a goal to democratize wearable haptics we introduce VHP, a vibrotactile haptics platform. It includes a low-power miniature electronics board that can drive up to 12 independent channels of haptic signals with arbitrary waveforms at a 2 kHz sampling rate. The platform can drive vibrotactile actuators including linear resonant actuators and voice coils. The control hardware is battery-powered and programmable, and has multiple input options, including serial and Bluetooth, as well as the ability to synthesize haptic signals internally. We developed current-based loading sensing, thus allowing for unique features such as actuator auto-classification, and skin-contact quality sensing. Our technical evaluations showed that the system met all our initial design criteria and is an improvement over prior methods as it allows all-day wear, has low latency, has battery life between 3 and 25 hours, and can run 12 actuators simultaneously. We demonstrate unique applications that would be time-consuming to develop without the VHP platform. We show that VHP can be used as bracelet, sleeve and phone-case form factors. The bracelet was programmed with an audio-to-tactile interface and was successfully worn for multiple days over months by developers. To facilitate more use of this platform, we open-source our design and plan to make the hardware widely available. We hope this work will motivate the use and study of vibrotactile all-day wearable devices.