Unit 1_9 Human Computer Interface

Why have an Interface? The user needs to issue instructions Problem diagnosis The Computer needs to tell the user what to do

What do you need to Think about? When designing an HCI you need to consider: Task User experience User preference Resources

General Features Appropriate input methods Use of colour Consistency Pictures/Icons Text Sound

Types of HCI Command Line Graphical user interfaces Menu driven interfaces Form driven interfaces Natural language interfaces Voice control Graphical devices Game playing Touch sensitive screens Biometric

Command Line When computers were first created the lack of graphical abilities meant that all user interfaces were command line based.

Command Line Advantages Quicker that using a GUI for some tasks More control for the user Disadvantages Very difficult for beginners Have to remember loads of commands Have to be very careful of syntax EXAMPLE

Graphical User Interface Graphical user interfaces utalise graphics in order to code commands with pictorial representation. WIMP (Windows, Icon, Menus, Pointers) Drag and drop Task bars WYSIWYG Examples include Windows, LINUX, Snow leopard EXAMPLE

Graphical User Interface Advantages No need to learn commands Icons mean that novices can use the system The use of a mouse Disadvantages Needs more powerful computers More memory is needed Can be confusing using icons (undo)

Menu Driven Systems Use a restricted list of commands that the user can select Advantages Fewer options mean less likely to make data entry errors Easy systems to understand and use Context sensitive help can be provided Unsuitable choices can be hidden from the user Disadvantages Only really suitable for systems that have a few possible options Causes frustration for experienced users EXAMPLE

Form Driven Systems Used to collect information from the user. Advantages Validation checks can be applied Essential information can be forced (presence check) Disadvantages Only really has one purpose, gathering information from users.

Natural Language Interface Allows users to use their own spoken language to communicate with the computer. Via microphone or keyboard. Advantages Very easy to learn Disadvantages Computers have real problems interpreting natural language (context, dual means etc)

Voice Interfaces Uses voice recognition software to implement commands or input text onto a computer Advantages Faster than typing 99% accuracy Cheap Disadvantages Needs training Not accurate at first Errors due to background noise Not compatible with all software The reverse is called speech synthesis

Graphical Devices The tablet and pen system (have a look at the interactive board). Great for drawing or fine detail work. E.g. graphics or CAD

Game Playing Devices Joystick Cordless games controller Steering wheel Car pedals Gear sticks

Touch Sensitive Screens Allows a user to make selections by simply pressing options presented on the screen. (The most famous example to date is the itouch or iphone!). Great for menu driven systems!

Biometric Devices Retina Scan Fingerprints Hand prints Voice Face EXAMPLES