A Haptic Belt for Vibrotactile Communication

Troy McDaniel, Sreekar Krishna, Daniel Villanueva, Sethuraman Panchanathan Center for Cognitive Ubiquitous Computing

Arizona State University Tempe, Arizona, USA

{troy.mcdaniel, sreekar.krishna, daniel.villanueva, panch}@asu.edu

Abstract—Our sense of touch is largely underutilized—compared to vision or hearing—as a communication channel in today’s computer interfaces. This is true even when our skin, given its size, spatial acuity and temporal acuity, has shown immense potential as a communication modality, particularly, vibrotactile communication. One popular form factor in vibrotactile communication that researchers have been exploring is the waist-worn belt. In this demonstration, participants will experience vibrotactile cues for dancing through our novel vibrotactile belt implementation. Moreover, participants will learn about vibrotactile belt design guidelines, and how they cross over to vibrotactile wearables in general.

Keywords-Vibrotactile belt, haptic belt, vibrations, tactile, situational awareness, tactons, tactile icons

I. INTRODUCTION

Our visual and auditory modalities are often overloaded with information when interacting with today’s computer technology. It begs the question, “Why hasn’t our sense of touch been utilized as a communication modality when the potential is there?” Haptic interactions using touch screens on cell phones and touch tablets have been successful, but our tactile sense is still underutilized. In the research field of vibrotactile communication, we have the capability to discern information encoded—in terms of spatial and temporal variations—in vibrations, as shown in relatively recent tactile icons research [1] and earlier work [2]. Vibrotactile wearables come in all shapes and sizes—gloves, shirts, etc.—but a popular form factor with many applications is the waist-worn belt, i.e., vibrotactile or haptic belt [3][4]. We’ve chosen this form factor as a platform to explore vibrotactile communication, and improve upon existing design guidelines for these belts.

Our contribution is a new belt design and implementation using novel design guidelines targeting functionality,performance and usability requirements. These requirements, described in Table I, were compiled based on (1) related work, particularly [3], in which Lindeman et al. outline functionality requirements including expressiveness (capability to alter the dimensions of vibrations), scalability and reconfigurability;and (2) over a year of empirical evaluation through user studies and pilot tests during which extensive feedback was gathered.(For more information, the interested reader is referred to [5]for complete design details.)

Table I. Proposed design guidelines for vibrotactile belts.

II. DEMONSTRATION OF PROPOSED SYSTEM

In this demonstration, participants will wear our proposed vibrotactile belt—see Figure 1—and experience vibrations around their waist. The vibrotactile cues will correspond to basic dance movements, and hence, participants will learn simple dances by using our belt and the predefined vibrotactile patterns. Although just one of many possible applications of vibrotactile belts, we feel that this demonstration will provide participants with an interesting and engaging look at vibrotactile belts and their capabilities.

Figure 1. Our proposed vibrotactile belt design and implementation consisting of a belt harness; encased vibration motors; wiring; and a control box enabling

belt control, wireless connectivity and battery power supply.

The demonstration will also instruct participants on designing vibrotactile belts, and other form factors, using our proposed design guidelines. For example, the belt should be designed in such a way that it does not hinder movement and is

978-1-4244-6509-5/10/$26.00 ©2010 IEEE

unobtrusive (usability requirements); the belt should be reliable and durable (performance requirements); and the belt should have the capability to enable its vibratory dimensions to be altered (functionality requirement). Meeting these requirements, as well as those in Table I, will help ensure that the belt design will be applicable to a variety of applications.

Figure 2 provides a high-level overview of the belt’s implementation. The wireless connection between the belt and the computer provides the desired portability and limited cumber upon which the rest of the system is developed. The wireless haptic belt consists of a hierarchical microcontroller design with a main controller (Haptic Belt Controller) for PC or PDA communication and overall system maintenance, and auxiliary controller (Tactor Controller) for monitoring each vibration motor. While the main controller provides the user interface to access the tactors on the belt, the auxiliary controllers ensure fine control of amplitude (perceived level of vibration intensity) and timing of vibration for each motor. This multilayer architecture caters to the four important functional requirements of expressiveness, scalability, reconfigurability and portability. Any number of tactor modules, up to a maximum of 128, can be added to the belt without changing the firmware on the main controller (although we limited our implementation to 16 tactors or less). The functionality of the belt is exposed through an application programming interface, and can be leveraged through a command line (terminal control) or a graphical user interface for belt configuration and activation. Lastly, the graphical controls, written using the C# language and .NET components, allow easy configuration of complex vibrotactile rhythm patterns using text inputs and drop-down menu selections. Users can also specify tactor module locations, and query the wireless haptic belt for its current configuration. The software also provides utilities for creating spatio-temporal patterns using specified tactor modules and rhythms.

TactorModule(s)Tactor

Module(s)TactorModule(s)

GraphicalUser Interface

Haptic Belt Controller

TactorModule(s)

Hardware Drivers

Basic Console /Terminal Menu

Virtual COM Port

Wireless LinkZigBee (IEEE 802.15.4) or Bluetooth (IEEE 802.15.1)

I2CProtocol

UARTProtocol

Personal Computer Device HapticBelt

Figure 2. Overview of belt implementation.

REFERENCES

[1] S. Brewster and L. Brown, “Tactons: structured tactile messages for non-visual information display,” AUIC '04: Proceedings of the fifthconference on Australasian user interface, Australian Computer Society, Inc., 2004, 23, 15.

[2] F.A. Geldard, “Adventures in tactile literacy,” American Psychologist. Vol. 12(3), vol. 12, Mar. 1957, 115-124.

[3] R. Lindeman, Y. Yanagida, H. Noma, and K. Hosaka, “Wearable vibrotactile systems for virtual contact and information display,” Virtual Reality, vol. 9, Mar. 2006, 203-213.

[4] J.B.F.V. Erp, H.A.H.C.V. Veen, C. Jansen, and T. Dobbins, “Waypoint navigation with a vibrotactile waist belt,” ACM Trans. Appl. Percept., vol. 2, 2005, 106-117.

[5] N. Edwards, J. Rosenthal, D. Moberly, J. Lindsey, K. Blair, S. Krishna, T. McDaniel, and S. Panchanathan, “A pragmatic approach to the design and implementation of a vibrotactile belt and its applications,” IEEE International Workshop on Haptic Audio Visual Environments and Games, 2009, 13-18.