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

2. 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

3. 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

4. Input Devices
Keyboards, keypads & buttons
Pointing devices

5. 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?

7. 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

8. 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?

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

11. Output Devices
Screens
Loudspeakers
Simple output devices

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

13. 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?

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

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

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

17. Questions?