Choosing interaction devices: hardware components Chapter 12 Choosing interaction devices: hardware components

Introduction Every user interface consists of a mixture of design components Hardware components: also known as I/O devices, or interaction devices Software components: generated by the underlying computer program

Choosing Interaction Devices Interaction devices are tools used to complete a job To choose between devices, you need to ask the right questions Questions are driven by constraints of the technology and by the uses to which the technology will be put

Input Devices Keyboards, keypads & buttons Pointing devices

Input Devices Keyboards, keypads & buttons Discrete input devices: can be used to enter individual items of information Questions: What size do the keys need to be? What shape should the keyboard be? How robust does the keyboard need to be? Which keys/buttons are needed and how should they be labeled?

Input Devices Pointing Devices Continuous input devices: good at tasks that cannot be split easily into a number of discrete steps 2 types: Indirect: require the user to move a screen cursor using a secondary device Direct: allow user to point directly at the relevant position on the screen

Input Devices Pointing Devices Questions: How easy to learn does the device need to be? How accurate does the device need to be? How much time will the user spend on the system? How much space is there? How robust does the device need to be? How manually dexterous is the user?

Input Devices Alternative Approaches Gesture Iris & fingerprint recognition Eyetracking Handwriting recognition Speech recognition

Output Devices Screens Loudspeakers Simple output devices

Output Devices Screens Most common Can represent a wide variety of visual elements CRTs & LCDs

Output Devices Screens Questions How detailed does the image need to be? How many colors are needed? How large does the screen need to be? Does the screen need to be portable? How much space is there?

Output Devices Loudspeakers Questions How are the speakers going to be used?

Output Devices Simple output devices Lights, dials, gauges and buzzers Questions Will the data being output be better represented in analog or digital form?

Output Devices Alternative approaches Head-up displays Head-mounted displays (virtual reality systems) Stereoscopic displays

Questions?