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

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

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

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

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.

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.

Interaction Device Introduction Devices Input Devices Output Devices

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

Text-Entry Devices Keyboards Other text-entry devices

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

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

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

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

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

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

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

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 = 4433555[pause]555666 surprisingly fast! T9 predictive entry type as if single key for each letter use dictionary to ‘guess’ the right word hello = 43556 … but 26 -> menu ‘am’ or ‘an’ Text-Entry Devices

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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