1. Copyright 1999 all rights reserved Input Devices n What types are there? n Why do we need them? –What functions do they perform? n What are desirable characteristics for an input device? ?

2. Copyright 1999 all rights reserved Input Device Types Trackball Joystick Graphic tablet Touch screen Stylus Mouse Keyboard Scanner Voice input Touch pad Gaze Glove

3. Copyright 1999 all rights reserved Generating Computer Input n Humans need mechanisms for communicating with their computers n the type of mechanism depends on the type of input required by the computer ?

4. Copyright 1999 all rights reserved Generating Computer Input n Since computers support such a large variety of tasks, a large number of input mechanisms exist n There is no all- purpose input device!!! –the keyboard is the most general one.

5. Copyright 1999 all rights reserved Desirable Characteristics n Human performance –Speed and accuracy –Learning n Human protection –Fatigue and comfort –Repetitive stress injury

6. Copyright 1999 all rights reserved Desirable Characteristics n Match to Special Environments –Space and grime –Hands occupied –Minimal desk space –Mobile n Match to Task

7. Copyright 1999 all rights reserved Typical User Tasks n Point to object on screen n Select object n Motion –Draw –Drag –Move –Position –Orient

8. Copyright 1999 all rights reserved Evaluating Device Characteristics n Direct vs. Indirect –Direct--operates on the screen –Indirect--different location, e.g., desktop n Mapping of motion –Direction –Distance –Speed

9. Copyright 1999 all rights reserved Trackball n Spherical object rotates freely in a socket n Direction and speed translate to cursor movement n Usually has buttons

10. Copyright 1999 all rights reserved Trackball n Good for –Pointing –Selecting –Portable computers n Not so good for –Drawing –Dragging

11. Copyright 1999 all rights reserved Joystick n Stick or bat anchored at bottom n Motion is X-Y or 360° n Fingertip or hand grip n Motion “steers” cursor n Some respond to pressure, not motion

12. Copyright 1999 all rights reserved Joystick n Good for –Games –Flying aircraft –Point designation –Handicapped individuals n Not so good for –Drawing –Fine selection

13. Copyright 1999 all rights reserved Graphics Tablet n Surface sensitive to light, heat, RF, or touch n Operated with finger, light/RF pen, or stylus n Cursor tracks movements on tablet

14. Copyright 1999 all rights reserved Graphics Tablet n Good for –Drawing –Tracing –Digitizing –Handwriting –Two handed input n Not so good for –Cramped spaces –Selection

15. Copyright 1999 all rights reserved Touch Screen n Surface on computer screen is sensitive to touch n Finger or stylus n Pressure or light blockage n Cursor tracks touch motion press here

16. Copyright 1999 all rights reserved Touch Screen n Good for –Gross selection –Novice Users –Special environments Shop floorShop floor KiosksKiosks Burger KingBurger King n Not Good for –Constant use –Drawing

17. Copyright 1999 all rights reserved Light Pen or Stylus n Surface on computer screen is sensitive to special stylus n Cursor tracks stylus motion

18. Copyright 1999 all rights reserved Pen or Stylus n Good for –Freehand drawing –Handwriting recognition Palm Pilot & NewtonPalm Pilot & Newton –Pointing n Not good for –Writing tasks –Dragging

19. Copyright 1999 all rights reserved Mouse n Rectangular, movable control n Cursor tracks mouse motion n Usually has one, two, or three buttons n Currently most common pointing device

20. Copyright 1999 all rights reserved Mouse n Good for: –Pointing –Selecting –Dragging –Grabbing n Not so good for: –Drawing –Cramped spaces

21. Copyright 1999 all rights reserved Keyboard n “Standard” typewriter keyboard n Cursor movement keys n Additional function keys

22. Copyright 1999 all rights reserved Keyboard n Currently most common input device n Various layouts –QWERTY –Dvorak –Chord –Ergonomic split, etc.

23. Copyright 1999 all rights reserved Other Input Devices Not as common…yet!

24. Copyright 1999 all rights reserved Scanner n For digitizing information –Graphics –Text n Easier to draw on paper and digitize input than to draw on computer

25. Copyright 1999 all rights reserved Voice Input n Good for –Limited vocabulary input –Hands free tasks –Handicapped users n Bad for –Natural language understanding –Casual users

26. Copyright 1999 all rights reserved Glove n Good for: –Grabbing –Pointing –Tactile sensation –3-D tasks –Telerobotics n Not so good for: –2-D environments –Drawing

27. Copyright 1999 all rights reserved Gaze n Gaze is the process of making menu selections with one’s eyes n Uses an eye tracking device n Head mounted or heads up displays –user has a see through visor in front of their eyes on which the computer display is projected –fighter pilots and repair personnel doing complex repair tasks use head-mounted displays

28. Copyright 1999 all rights reserved Gaze n Good for –Handicapped personnel –Tasks requiring both hands flyingflying repairrepair n Not so good for –Normal selection tasks –Very tiring & difficult to use