1. Input Devices and Interaction Techniques I. Scott MacKenzie Summarized and Augmented by Geb Thomas

2. Introduction Input and output between people and machines New technology, new challenges Interaction experiments and models

3. Transducers Convert energy -- often mechanical to electrical Switches (mechanical and photoelectric) Isotonic (displacement) joysticks - position encoders Isometric (force sensing) joysticks - strain guages Microphones

4. A Mouse

5. Joysticks http://www.vrealities.com/control.html http://www.thevrsource.com/

6. Gloves Cyberglove http://www.virtex.com/products/hw_products Pinch glove

7. Trackers Polhemus (Fast Track) Flock of Birds (Virtex) Intersence (IS300)

8. Device Models Buxton’s taxonomy -- articulation, number of dimensions, type of sensing (position, motion, pressure), motor skills (touch vrs mechanical) Foley tasks -- select, position, orient, path, quantify and text entry -- emphasizes mappings Very few engineering models

9. Device Parameters Resolution Sampling Rate Lag Optimality and control gain Some of these are determined by hardware, some by software, some by transducer characteristics

10. Resolution Nonlinearity, monotonicity, offest and gain

11. Sampling Rate Often 10-100 Hz Too slow for gesture capture Nyquest frequency

12. Lag Time difference between controller input and display 3D trackers range 30 - 250 mx, depends on sampling rate, update rate and software overhead.

13. Optimality and Control Gain Tunable parameters, such as mouse gain Selection task optimization does not consider “human engineering factors” such as –Ease of learning –skill retention –fatigue –effort –strees

14. Mouse Gain

15. Nonlinear Gain Vd = k*Vc^2

16. Interaction Movement is of increasing importance Many researchers considering mapping of 2D -> 3D Must be trained Limited metaphors Perceptual structure requires good match between input space and output space –Twisting for dials, shoving for movement, 2D for 2D, 3D for 3D

17. Gestures The great new era :) Writing, scribbling, annotating, pointing, nodding, etc. Editing proofreaders marks Transcribing musical notation Brush strokes

18. Tactile and Force Feedback Good input requires good feedback shape encoding in manual controls Character drawing the Octagon, a 24x6 matrix of pins Minski’s sandpaper Akamatsu and Sato’s variable friction Zimmerman’s pinch glove