1. 1 RodDirect : Two-Dimensional Input with Stylus Knob Motoki Miura and Susumu Kunifuji Japan Advanced Institute of Science and Technology, JAPAN MobileHCI2006@Espoo Finland

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

3. 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. 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. 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. 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

7. 7

8. 8 Metaphors (Scrolling and Moving object)

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

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

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

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

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

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

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

16. 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. 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. 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. 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. 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. 21 Drag (panning by pushing background)

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

23. 23 Tilt (PhidgetAccelerometer attached on behind)

24. 24 RodDirect

25. 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. 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. 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. 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. 29 Questions & comments  Thank you for your attentions!!  Contact: –Motoki Miura –miuramo@jaist.ac.jp –http://css.jaist.ac.jp/~miuramo/

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