1. Understanding & Modeling Input Devices

2. Questions 1. How do common input devices work? 2. How can we think about the larger space of all possible input devices? 3. Can we predict human input performance? 4. What about uncommon input devices (multitouch, tangible interfaces, …)? 5. Will this be on the exam? Yes.

3. Today’s lecture in graphic form

4.  I think my keyboard is broken.  Whenever I have a few keys pressed down, some keys suddenly don’t work anymore; at other times ‘phantom’ characters appear.  What’s going on?

5. Keyboard

9. Microprocessor and Controller

10. Row/Column Scanning  9 lines and 20 keys http://v.youku.com/v_show/id_XMTI5NjE0OTQ4.html

11. Closeup

12. One key down

14. 3 Keys Down

15. Encoding keyboard: Keys conflict  C1-R1-C2-R2  3 or 4 keys  Q,W,A,S http://www.upsdn.net/html/2006-10/760.html

16. A Layered Framework From: Hartmann, Follmer, Klemmer: Input Devices are like Onions

17. Mouse Mouse. Engelbart and English ~1964

20. Encoder wheel for scrolling Left button Right button

21. IR emitter IR detector slotted wheel (between emitter & detector)

22. Sensing: Rotary Encoder

23. Sensing: Fwd rotation

24. Sensing: Backwd Rotation

25. Solutions: Use two Out-of-Phase Detectors

26. Sensing: Rotary Encoder

28. Transformation  cx t = max(0, min( s w, cx t-1 +dx*cd ))  cy t = …  cx t : cursor x (horizontal) position in screen coordinates at time t  dx: mouse x movement delta in mouse coordinates  s w : screen width  cd: control-display ratio

29. Device Abstraction  Click, DoubleClick, MouseUp, MouseDown, MouseMove …

30. What about optical mice? Source: http://spritesmods.com/?art=mouseeye

32. Trackball, Trackpad

33. Trackpoint  Indirect, force sensing, velocity control  Nonlinear transfer function

34. Joystick

35. A design space of input devices… Card, S. K., Mackinlay, J. D., and Robertson, G. G. 1991. A morphological analysis of the design space of input devices. ACM TOIS 9, 2 (Apr. 1991), 99-122.

38. Which is faster?

39. Engelbart

40. Experiment: Mice are fastest!

41. Fitts’s law  Time T pos to move the hand to target (size S) which is distance D away is given by: T pos = a + b log2 (D/S + 1) Index of Difficulty (ID) Only relative precision matters Exam Question Material! Source: Landay, James. “Human Abilities”. CS160 UC Berkeley.

43. T pos = a + b log2 (D/S + 1) Device Characteristics (bandwidth of human muscle group & of device) a: start/stop time (intercept) b: speed (slope)

44. Bandwidth of Human Muscle Groups

45. Why is mouse fastest?  Why these results?  Time to position mouse proportional to Fitts’s Index of Difficulty ID.  [i.e. how well can the muscles direct the input device]  Therefore speed limit is in the eye-hand system, not the mouse.  Therefore, mouse is a near optimal device.

46. Fitts’s law example  Which will be faster on average?  pie menu (bigger targets & less distance)

47. Fitts’s law in Windows &Mac OS The Apple menu in Mac OS X v10.4 Tiger. Windows 95: Missed by a pixel Windows XP: Good to the last drop

48. In office 2007 Larger, labeled controls can be clicked more quickly Magic Corner: Office Button in the upper-left corner Mini Toolbar: Close to the cursor Source: Jensen Harris, An Office User Interface Blog : Giving You Fitts. Microsoft, 2007.

49. Uncommon Input Devices  Assumptions so far:  Single user, working in front of a desktop PC  Main tasks are typing and pointing  Efficiency rules  What if we change these assumptions?  Design for enjoyment / engagement  Design for multi-user scenarios

50. Position+Orientation: Nitendo Wii

51. Camera based input: IO Brush  Source: Kimiko Ryokai, http://web.media.mit.edu/~kimiko/iobrush/

52. Multi-touch Jeff Han, Perceptive Pixel http://www.tudou.com/programs/view/LfwscZ1iUXc/

53. Hybrids: Devices on Tables Hartmann, Björn, Morris, M.R., Benko, H., and Wilson, A. Augmenting Interactive Tables with Mice & Keyboards. In Proceedings of UIST 2009.

54. http://www.vid3o.net/view/v_AvkV286mI/uist09- augmenting-interactive-tables-with-mice-keyboards.html

55. Hybrids: Multi-touch on Mice Mouse 2.0: Multi-touch Meets the Mouse Nicolas Villar, Shahram Izadi, Dan Rosenfeld, Hrvoje Benko, John Helmes, Jonathan Westhues, Steve Hodges, Eyal Ofek, Alex Butler, Xiang Cao and Billy Chen. Proceedings of UIST 2009. http://www.disclose.tv/action/viewvideo/31170/Mouse_2 _0_from_Microsoft/

56. Links  http://bjoern.org http://bjoern.org  http://research.microsoft.com/apps/video/ default.aspx?id=144849 http://research.microsoft.com/apps/video/ default.aspx?id=144849