1 RodDirect : Two-Dimensional Input with Stylus Knob Motoki Miura and Susumu Kunifuji Japan Advanced Institute of Science and Technology, JAPAN Finland

2 Outline  Motivation  RodDirect –Concept –Applications –Implementation of Prototype  Experiment  Conclusion

3 Conventional Input Devices for Portable Handhelds  Consideration of Size and Weight  Common input devices –Buttons/Hot keys –Touch sensitive panel with stylus pen –Mini Keyboard –Jog Dial  Touch panel is versatile, but … –Often requires precise tapping for small GUI objects –Stylus pen is necessary for precise tapping –Drawing/Storing actions disturb smooth interaction

4 Augmented Approach  Exploit physical movement with natural interaction –Efficient use of device portability  Embed sensors –Position & Orientation [ “ Chameleon ”, Fitzmaurice et al. 1993] –Tilting [Rekimoto 1996] –Tactile(Haptic) [Harrison et al. 1998][Hinckley et al. 2000]  Data transfer in real world context –HyperPalette [Ayatsuka et al. 1999] –Toss-it [Yatani et al. 2004]

5 Trend of new device development  Attaching more sensors on handheld –Detect natural behavior of human with handling devices –Recognize intension of user  We agree the direction of approach  However, we should make full use of conventional hardware as much as possible

6 RodDirect  Novel, simple and versatile interaction technique  RodDirect utilize stylus pen as a knob/cylinder  Two types of stylus movement in the stylus holder are associated with parameters –(1) Twist (Rotation) –(2) Push/Pull (Sliding)  User can control two parameters intuitively and simultaneously

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8 Metaphors (Scrolling and Moving object)

9 Applications using RodDirect Block BreakerSpace Invader Application Switching Scheduler Map Browser

10 Application: Map Browser 2D Scrolling Zooming by rotating while pressing button “ Crutching ” by pressing button

11 Application Switching (conceptual demo) Twisting for switch command Pulling out determines screen mode

12 Application: Scheduler (mixed with touch screen interaction) 2D Scrolling Tapping & Holding to move item

13 Game: Block Breaker Controlling pad position directly by rotating/sliding

14 Game: Space Invader Controlling cannon position directly by sliding Shot by rotating (player can control laser speed by rotation speed)

15 Prototype (Optical mouse sensor detects movements of stylus) 800 counts/inch, 420 counts/rotation, 1200 counts/one-way slide

16 Implementation of Prototype  PC receives location of stylus as ordinary mouse position  PC-PDA connection (ActiveSync) to transmit location to PDA  Application on PDA processes the location USB port TCP/IP

17 User’s Merits  Natural and Intuitive  User can operate with normal stylus  Physical constraint of holder decreases difficulty of operation –non-dominant hand control is also possible  Friction keeps the position of stylus –User can suspend/resume tasks immediately

18 Manufacturer’s Merits  The sensor is relatively small –It can be embedded in the device –Few restriction in exterior design  Not expensive  Provides new experience for users

19 Tasks and Interactions with handheld Launch Application Hot Key 1D Scrolling 2D Scrolling Discrete Tap&Drag (ex.Inputting Text) Cursor Keys Jog Dial RodDirect Touch Panel with Stylus Cost of Operations (incl. Pre/Post Tasks) Task Complexity

20 Experiment  Purpose: Investigate efficiency of RodDirect  Task: Scroll to center target & press button  Target appears on 1280x1200 virtual screen  9 participants  4 input methods –Drag –Walk –Tilt –RodDirect  Captured time to complete task

21 Drag (panning by pushing background)

22 Walk (similar to Touch-n-go [MacKay et al. 2005])

23 Tilt (PhidgetAccelerometer attached on behind)

24 RodDirect

25 Result (Estimated marginal means) Bonferroni pair-wise comparison revealed: Rod<<Walk Rod<<Tilt Drag<<Walk Drag<<Tilt Walk<<Tilt But no significant differences found between Rod and Drag **

26 Fitting to MacKenzie model (MT = a + b log 2 (Distance/Size + 1) Slope (b)  Rod:547  Drag:769  Walk:844  Tilt:785 Rod Drag Walk Tilt

27 Findings  RodDirect can operate as fast as tap&drag –Rod becomes faster when larger target size, longer target distance  User Comments –Drag suits for precise control –Drag exhausted user by back/forth dragging –Participants disrupted by reflections from room light in Tilt  Tilt is not best for screen-attentive tasks –Touch panel was worn out by frequent scratch

28 Conclusion  RodDirect –novel, simple and versatile interaction technique –Suitable for mobile appliances  Relatively small sensor  Less influence on exterior design if embedded –Effective for scrolling task  RodDirect can be applied not only PDA with stylus but also “ rod antenna ” of cellular phone

29 Questions & comments  Thank you for your attentions!!  Contact: –Motoki Miura –

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31 Longer Stylus Length: Original: 94mm Longer : 110mm (+16mm) (To Prevent pushing in entirely)