1. Interaction Devices: Input Devices
Lecture 11
Date: 9th March

2. Overview of Lecture General introduction to input/output devices
Input Devices
Text entry devices
Keyboards
Handwriting Recognition
Speech Recognition
Positioning and pointing devices
Direct control devices
Indirect control devices
Devices for disabled
Output Devices

3. Interaction Device Introduction
An early input/output device: ASR33 teletype :

4. Interaction Device Introduction
Screen, or monitor, on which there are windows
Keyboard
Mouse/trackpad
Variations
desktop
laptop
PDA
The devices dictate the styles of interaction that the system supports
If we use different devices, then the interface will support a different style of interaction

5. Interaction Device Introduction
Cannot separate interface function from I/O interaction devices.
Majority of current interfaces designed to operate with keyboard and mouse.
New interaction styles and devices are required to support inputs such as voice input, gesture recognition, 3-D pointing, haptic interaction, wearable computers.

6. Interaction Device Introduction
Devices should be easy and pleasant to use, fast to learn, with minimal effort and error. They generally involve physical actions of dragging, clicking, typing, speaking, writing, etc.
Different devices have different affordances, and differing capacity for accuracy and feedback.
Also need to consider issues such as fatigue and long term health effects.

7. Interaction Device Introduction
Devices
Input
Devices
Output
Devices

8. Input Devices
An input device is a device that, together with appropriate software, transforms information from the user into data that a computer application can process
Input devices can be categorised into
Text entry devices
Positioning and pointing devices
Devices that input pictures
Devices that input Sound

9. Text-Entry Devices Keyboards Other text-entry devices

10. Keyboards Most common input method
Discrete entry device (I.e. involves sensing one of two or more positions)
Physical design of keys and key groupings should be considered
A key-press closes a connection, causing a character code to be sent to the computer
Connection is usually via a lead, but can be wireless
Text-Entry Devices

11. Keyboards Keyboards Types: QWERTY Alphabetic Chord Dvorak Braille
Mobile Phone Keyboard
Text-Entry Devices

12. QWERTY Keyboards Named from topmost left letters Most common keyboard
Based on typewriter key layout design – designed to prevent jamming of the keys
Not optimal for typing – frequently used letters placed far apart thereby increasing finger travel distances
Cost of replacement perpetuates use
Text-Entry Devices

13. Alphabetic Keyboards Keys arranged in alphabetic order
not faster for trained typists
not faster for beginners either
No inherent advantage
Sometimes used in personal organisers
Text-Entry Devices

14. Chord Keyboards Only a few keys - four or 5
Letters typed as combination of key-presses
Compact size - ideal for portable applications
One handed use
Short learning time
Fast
But fatigue after extended use
Sample use – transcript recording in court
Text-Entry Devices

15. Dvorak Keyboards common letters under dominant fingers
biased towards right hand
common combinations of letters alternate between hands
10-15% improvement in speed and reduction in fatigue
But - large social base of QWERTY typists produce market pressures not to change
Text-Entry Devices

16. Braille Keyboards
Keyboard especially adapted to blind or visually impaired users
Keys are embossed to enable identification of keys
Frequently used with “voice output” systems
Text-Entry Devices

17. Mobile Phone Keyboards
use numeric keys with multiple presses
2 – a b c 6 - m n o
3 - d e f 7 - p q r s
4 - g h i 8 - t u v
5 - j k l 9 - w x y z
hello = [pause]555666
surprisingly fast!
T9 predictive entry
type as if single key for each letter
use dictionary to ‘guess’ the right word
hello = …
but 26 -> menu ‘am’ or ‘an’
Text-Entry Devices

18. Other Text Entry Devices
Handwriting recognition
Handwritten text is input into the computer, using a special pen and typically, a small notebook sized computer with a screen that the user can write directly onto.
Attractive as a text entry method because handwriting is a common familiar activity
Handwriting recognition software translates handwritten characters into ASCII text that can be displayed instantly on screen as printed characters
Handheld organizers – Apple Newton (the first), Psion, Palm, PocketPC (from Microsoft)
Text-Entry Devices

19. Speech Recognition
Speech recognition technology replaces a computer keyboard with a microphone and software to change the spoken word into typed characters
Natural form of communication, easier to train new users than other input devices
Does not require hands or other limbs – operators can carry out other actions
Offers disabled people (particularly blind, motor impairment) the opportunities to use new technology
Limited by recognition error rate of speech recognition systems
Variety of accents and intonations increase error rate
External noise interfering
Text-Entry Devices

20. Speech Recognition Primary components of a speech recognition system:
Speech capture device = Microphone and associated analog-to-digital converter that digitally encodes the speech waveform
Digital signal processing module – detects word boundaries and separates useful speech information other unimportant data
Specialised speech recognition software, incorporating reference speech patterns, and pattern matching algorithms
Text-Entry Devices

21. Speech Recognition
Speech recognition systems can be categorised by number of users:
Speaker-dependent system require each user to train a system to recognise their voice
Speaker-independent systems try to accommodate a large range of speaking characteristics and vocabulary
Text-Entry Devices

22. Positioning & Pointing Devices
Pointing devices are applicable in six types of interaction tasks:
1. Select:
user chooses from a set of items.
used for traditional menu selection, identification of a file in a directory, or marking of a part in an automobile design.
2. Position:
user chooses a point in a one-, two-, three-, or higher-dimensional space
used to create a drawing, to place a new window, or to drag a block of text in a figure.
3. Orient:
user chooses a direction in a two-, three-, or higher-dimensional space.
direction may simply rotate a symbol on the screen, indicate a direction of motion for a space ship, or control the operation of a robot arm.
Positioning & Pointing Devices

23. Positioning & Pointing Devices
4. Path:
user rapidly performs a series of position and orient operations.
may be realized as a curving line in a drawing program, the instructions for a cloth cutting machine, or the route on a map.
5. Quantify:
user specifies a numeric value.
usually a one-dimensional selection of integer or real values to set parameters, such as the page number in a document, the velocity of a ship, or the amplitude of a sound.
6. Text:
user enters, moves, and edits text in a two-dimensional space. The
pointing device indicates the location of an insertion, deletion, or change.
more elaborate tasks, such as centering; margin setting; font sizes; highlighting, such as boldface or underscore; and page layout.
Positioning & Pointing Devices

24. Positioning & Pointing Devices
Pointing devices are generally fast and easy to use, but require hand-eye coordination.
Can be divided into:
direct control devices
indirect control devices
devices for disabled
Positioning & Pointing Devices

25. Positioning & Pointing Devices
General Devices
Indirect pointing device
Mouse
Trackball
Joystick
Touchpad
Direct control pointing device
Touch-Sensitive screens
Light Pen
Devices for the Disabled
Eyegaze device
Eye Typer
Head movement tracker
Positioning & Pointing Devices

26. Positioning & Pointing Devices
Indirect Pointing Devices – Mouse
Requires physical space for movement
Provides relative motion
Can be difficult for novice users (indirect mapping)
Two characteristics: planar movement, and buttons
Positioning & Pointing Devices

27. Positioning & Pointing Devices
Indirect Pointing Devices – Trackball
Weighted ball is rotated inside a static housing
Compact -> Good for limited space situations – e.g. laptops
Difficult for long movements
Requires separate buttons for select
Positioning & Pointing Devices

28. Positioning & Pointing Devices
Indirect Pointing Devices – Joystick
Usually used for tasks incorporating direction and speed rather than location
Compact - requires very little space
Compact, must be stable
Absolute (movement) and isometric (direction and velocity)
Inexpensive and robust
Often found in computer games
Positioning & Pointing Devices

29. Positioning & Pointing Devices
Indirect Pointing Devices – Touchpad
Typically used in portable computers to replace mouse
+ requires minimal space (typically 2-3 inches in size
- can be difficult and inaccurate to use
Positioning & Pointing Devices

30. Positioning & Pointing Devices
Direct Control Pointing Devices – Touch Sensitive Screens
allows direct control touches on the screen using a finger
lift-off strategy enables users to point at a single pixel
the users touch the surface
then see a cursor that they can drag around on the display
when the users are satisfied with the position, they lift their fingers off the display to activate
can produce varied displays to suit the task
are fabricated integrally with display surfaces
Positioning & Pointing Devices

31. Positioning & Pointing Devices
Direct Control Pointing Devices – Light Pens
enabled users to point to a spot on a screen and to perform a select, position, or other task
it allows direct control by pointing to a spot on the display
incorporates a button for the user to press when the cursor is resting on the desired spot on the screen
Disadvantages:
users' hands obscured part of the screen,
users had to remove their hands from the keyboard,
users had to pick up the lightpen
Positioning & Pointing Devices

32. Positioning & Pointing Devices
Devices for Disabled – EyeGaze Device
An eyegaze unit is worn on a headband on the users head - screen cursor is driven by users eye movements
+ good for disabled users with motor impairments or any environment where user is limited in movement
+ Fast
+ accurate
- Expensive
- Good for selection, but not for continuous movement of cursor
Positioning & Pointing Devices

33. Positioning & Pointing Devices
Devices for Disabled – Eye Typer Device
Developed for users with severe motor impairment
The user “types” by scanning the keyboard and fixing momentarily on each character that is wanted
The characters are displayed on a panel in qwerty keyboard layout. Each character has a light embedded in it. The display has a camera that can detect which character the user is looking at.
Positioning & Pointing Devices

34. Positioning & Pointing Devices
Devices for Disabled – Head Movement Tracker
Developed for users with severe motor impairment
The user wears a lightweight headset. The “keyboard” is a display on the screen. The system detects slight movements of the user’s head to move cursor. To operate a key, user moves cursor to the key and blows on a blow switch
Positioning & Pointing Devices

35. Positioning & Pointing Devices
Other Device Types
Picture Entry devices
Scanners
Video cameras
MPEG camera
Sound entry devices
Microphone
Positioning & Pointing Devices

36. Summary of Lecture Input Devices Text entry devices
Keyboards – QWERTY, Alphabetic, Chord, Dvorak, Braille
Handwriting Recognition
Speech Recognition
Positioning and pointing devices
Direct control devices
Mouse
Trackball
Joystick
Touchpad
Indirect control devices
Touch-Sensitive screens
Light Pen
Devices for disabled - Eyegaze device, Eye Typer, Head movement tracker
References

37. Terms of Reference
Shneiderman, B. & Plaisant, C. (2005) Designing the User Interface
Preece, J. et al. (2002) Interaction Design
Benyon, D. et al (2005) Designing Interactive Systems
Helander, M. et al (1997) Handbook of Human-Computer Interaction
Norman, D. (1990) The Design of Everyday Things
References