Interactive Generator: A Self-Powered Haptic Feedback Device Akash Badshah 1 , Sidhant Gupta 2 , Gabe Cohn 2 , Nicolas Villar 3 , Steve Hodges 3 , Shwetak N Patel 2 1 Phillips Exeter Academy Exeter, NH (USA) akashbad@comcast.net 2 University of Washington UbiComp Lab, DUB Group Seattle, WA (USA) {sidhant, gabecohn, shwetak}@uw.edu 3 Microsoft Research Cambridge, UK {nvillar, shodges} @microsoft.com ABSTRACT We present Interactive Generator (InGen), a self-powered wireless rotary input device capable of generating haptic or force feedback without the need for any external power source. Our approach uses a modified servomotor to per- form three functions: (1) generating power for wireless communication and embedded electronics, (2) sensing the direction and speed of rotation, and (3) providing force feedback during rotation. While InGen is rotating, the de- vice is capable of providing the sensation of detents or bumps, changes in stiffness, and abrupt stops using only power that is harvested during interaction. We describe the device in detail, demonstrate an initial ‘TV remote control’ application, and end with a discussion of our experiences developing the prototype and application. To the best of our knowledge, InGen is the first self-powered device, which also provides haptic feedback during operation. More broadly, this work demonstrates a new class of input sys- tems that uses human-generated power to provide feedback to the user and wirelessly communicate sensed information. Author Keywords Self-powered, human-powered, force feedback, haptics, tactile feedback, user interface device, remote control ACM Classification Keywords H.5.2 [Information interfaces and presentation]: User Inter- faces. – Input devices and strategies General Terms Design, Experimentation INTRODUCTION Haptic feedback refers to the force experienced when an object is touched or physically manipulated. It is an essen- tial part of human interaction with physical objects, includ- ing electronic devices. Notably it provides a useful interac- tion channel independent of sound and vision, which are predominant in today’s digital interfaces. Moreover, haptic feedback serves as a primary input modality to convey in- formation when auditory and visual feedback may not be appropriate or available. However, with the exception of vibrating cellphone alerts, computer-controlled haptic feed- back (sometimes called force feedback) it is not yet ubiqui- tous. Even so, other forms of haptic feedback, such as elec- tronic control of temperature, stiffness and texture, are po- tentially valuable. Unfortunately, the electric motors, solenoids, or other elec- tromechanical actuators employed in many force feedback systems have significant power requirements. This seems inevitable since haptic feedback ultimately relies on electri- cal energy to affect physical movement. This in turn, limits mobile applications where battery life is an important fac- tor. As such, many of the haptic design schemes reported in the HCI literature require external power supplies. The design goals of incorporating haptic feedback and re- ducing power consumption therefore seem inherently at odds with each other. However, this is not the case. Our system exploits unique properties of DC motors to provide rotational haptic feedback with no external power require- ments. We call this system the Interactive Generator, or InGen (see Figure 1). InGen uses a modified servomotor, to act simultaneously as (1) an input sensor, detecting the Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. CHI 2011, May 7–12, 2011, Vancouver, BC, Canada. Copyright 2011 ACM 978-1-4503-0267-8/11/05....$10.00. Figure 1: Interactive Generator is a self-powered general purpose wireless controller capable of providing haptic feed- back. CHI 2011 • Session: Touch 1: Tactile & Haptics May 7–12, 2011 • Vancouver, BC, Canada 2051