Design of Rhythm-Based Vibrotactile Stimuli Around the Waist: Evaluation of Two Encoding Parameters

In this paper, we propose two encoding parameters to facilitate the design of a rhythm-based tactile scheme for humans. The sense of touch has been used for many years to aid communication for people with sensory impairments. Now, vibrations are used in mobile phones and handheld computers but are generally very basic and do not fully exploit the potential of vibration as a means of communication. Several studies explored the use of tactile icons combining different parameters such as amplitude modulation, location, and duration. However, the parameter "rhythm" has not attracted a lot of attention. Using two parameters (mu(E), sigma(E)) to control the design of tactile-pattern sets, we created four stimulus schemes of 20 patterns each. Using a tactile belt located around the waist, 64 subjects tested them. The amount of static information transferred and response times (RTs) varied among the different designs. The scheme with the best set of encoding parameters (mu(E) = 3, sigma(E) > 0) conveyed 4 b of information or 16 tokens with an RT of 4.3 s.