Gesture Interfaces for Mobile Devices – Minimalist Approach for Haptic Interaction Jukka Linjama Nokia Technology Platforms Itämerenkatu 11-13, 00180 Helsinki, Finland jukka.linjama@nokia.com Jonna Häkkilä, Sami Ronkainen Nokia Multimedia Yrttipellontie 6, 90230 Oulu, Finland jonna.hakkila@nokia.com, sami.ronkainen@nokia.com ABSTRACT Due to the limited input and output functionalities and varying usage situations, haptics offers a potential approach for interacting with mobile handheld devices. In this paper, we discuss the specific features related to haptic interaction methods for mobile devices and argue for a minimalistic gesture control. In addition, the paper presents a haptic mobile phone application utilizing this design principle, and implementing sensor based movement detection and haptic feedback. Author Keywords Mobile devices, user interface, haptic interaction, tactile feedback, gesture input, acceleration sensors, multi-modal interfaces ACM Classification Keywords H5.2. User interfaces: Haptic I/O, Input devices and strategies, Interaction styles. INTRODUCTION Mobile phones are typically used in very different kinds of situations. Often this includes situations, where user’s full attention cannot be focused on the device or visual contact is hard, e.g. while riding a bicycle. The input methods used when interacting with the phone are limited, as they conventionally include small keypad or a pen-input. Thus, the actions usually require several button presses or pen strokes which makes the task completing slow, and the phone is hard to use for instance with gloves on. As an optional input technique, several mobile phones employ voice commands as an alternative input modality. However, speech input is often not fully functional option: it may not be socially suitable in a quiet environment, and the speech recognition may fail in noisy surroundings. In addition, it is often perceived as awkward to use in social situations. Addressing to these problems, haptic user interfaces offer an alternative way for interacting with a mobile phone. Haptic interfaces in mobile devices have many limitations in comparison to desktop usage, where e.g. precise position input is possible, and enough energy is available for force feedback. However, there are opportunities for haptic interfaces in mobile device domain as well. Despite the limitations in the actual fidelity in haptic sensing and feedback, the use context of mobile devices raises many needs for the end user that haptic interfaces can help to satisfy. For instance, there is a need for a mobile device user to be able to • control the device on the move, without access to keys • know the status of the device or application with very limited access to the display Haptic input methods have so far been used to modify the visual output on the screen. This has been demonstrated e.g. by [1], who use tilting the device for scroll content on a PDA display, and [4]. who additionally orientate the portrait and landscape view according to the device orientation. such as zooming or scroll the display. Context recognition has employed sensors to recognize different movements of the device, which information has then be used as an information source to determine e.g. if the user is walking or running [6], [3]. This paper addresses some of the opportunities with a demo [5] of minimalist gesture interface, which utilises the combination of inertial sensing and vibration feedback. GESTURE INPUT From the perspective of mobile devices, the technology used for gesture recognition becomes important. Traditionally, many gesture recognition systems have been based on visual recognition of gestures from a video stream, as e.g. in system described by O'Hagan et al [9]. Even though e.g. mobile phones equipped with an inbuilt camera are becoming more popular, the possibility of utilizing the technology for gesture recognition is limited. Robust