Mobile Design

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• Mobile Design

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Key Goals of Mobile Usability

• Functionality
• Discoverability
• Efficiency
• Accessibility
• Enjoyment

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Principles of mobile Usability

• Visibility of system status
• Users own language
• Users existing schemata
• User control
• Consistency
• Error prevention
• Recognition verses recall
• Flexibility
• Sensible error messages
• Good documentation and help

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Principles of Mobile Usability

• Nomadic capabilities
• Safety
• Ergonomics
• Self-recovery capabilities
• Ease of integration
• Simplicity
• Predictability
• Accessibility

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Key Trends in Mobile Devices

• Large colour screens
• Powerful navigation solutions
• Third-party software
• (XHTML, Java, Symbian)
• Transition from auditory to
• visual interaction

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User Profiles Overview

• The user profile helps you understand the
• users and what they do.
• Level of knowledge and experience
• Job and task characteristics
• Psychological characteristics
• Physical characteristics

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User Profiles Knowledge and Experience

• Product literacy
• System experience
• Application experience
• Task experience
• Other system use
• Education
• Reading level
• Typing skill
• Native language

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User Profiles Jobs and Tasks

• Mandatory or discretionary use
• Frequency of use
• Task importance
• Task structure
• Turnover rate
• Primary training
• Job category

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User Profiles PsychologicalCharacteristics

• Attitude and motivation
• Cognitive style
• Attention Threshold

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User Profiles Physical Characteristics

• Age
• Gender
• Handedness
• Physical challenges

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Presentation Models

• Describes the static characteristics of a
• user interface.
• Layout
• Organization
• Theme and style
• Attributes (fonts, colours)
• UI architecture

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Layers of Interaction Overview

• Layers of interaction refer to the discrete
• levels at which users interact with devices.
• Physical layer
• Logical layer
• Cognitive layer

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Layers of Interaction Physical Actions

• Physical actions include
• Viewing the screen
• Reading text output
• Pressing buttons
• Handwriting input
• Speech input
• Listening for audio cues
• Listening for speech output

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Physical Action Guidelines

• Use Select vs. Type
• Use consistent button placement
• Instil habits and leverage old ones
• Provide feedback with each button press
• Audible and visual
• Provide Undo or Back support
• Provide adequate margins for selector
• Around buttons and menus
• Name buttons clearly (Save vs. OK)

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Layers of Interaction Physical Senses

• Conduits with the physical layer of the
• device are the five senses
• Vision
• Hearing
• Touch
• Smell
• Taste

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Layers of Interaction Physical Movement

• Fitts law relates to movement time
• Bigger is better,
• especially for navigation
• items.
• Screen edges and
• corners should be used.
• Layers

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Layers of Interaction Memory

• Millers law relates to memory
• Human short-term memory can accommodate about
  seven unrelated pieces of information, plus or
  minus two, at a time.

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Memory Limitation Guidelines

• Small screens require careful consideration of
• information layout
• Content should be continuous (no blank lines)
• with - between content items
• Place most important content at top of display
• Integrate tasks across applications (future)
• Always display system status
• Use anticipatory design techniques
• Example common actions with phone number

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Layers of Interaction Physical Stress

• Galvanic skin response (GSR)
• As human stress increases, the electrical
• resistance of the skin decreases due to an
• increase in the activity of the sweat glands.

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Handheld Button Guidelines

• Provide an obvious Click feel when button is
• pressed (tactile feedback)
• Make button labels large and easy to read
• Button icons should be clearly understood and
• cross-cultural
• Use a consistent button layout pattern
• If Stylus is used, provide an indent target
  within
• the button surface Layers

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Layers of Interaction Human Speech

• Human speech research
• An average human can hear sound
• frequencies in the range from
• 20 hertz (Hz) to 20 kilohertz (kHz).
• Cultural differences in reaction to
• similar tones

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Human Speech Guidelines

• Keep tones in the 300Hz to 3kHz range
• Common range fundamental to speech
• Account for ambient noise and channel
• distortion
• Provide an alternative to speech to
• accommodate accessibility goals

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Layers of Interaction Physical Repetition

• Repetitive strain injury (RSI)
• Repetitive strain injury can occur any time a
• user is required to repeat an action over and
• over.

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Minimizing RSI Guidelines

• Provide softkeys closely associated with
• softkey labels
• Left softkey is Primary action, Right
• softkey as Alternate action
• Minimize text input, instead use selection
• whenever possible
• Minimize Triple Tap with UIs

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Layers of Interaction Logical Layer

• Logical aspects include
• Navigation
• Use of the software that operates the device
• Operating system

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Layers of Interaction Cognitive Layer

• Cognitive aspects include
• Menus
• Navigation elements
• Feedback
• Images

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Pen Interaction

• Pointing device and input mechanism
• Pen behaviours and gestures
• Ease of use is primary focus

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Pen Behaviour and Gestures

• Pressing
• Tapping
• Double-tapping
• Dragging

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Pen Gestures Graffiti
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Pen Design Tips

• Keep the interface simple
• Minimize character recognition
• Minimal number of windows
• Avoid secondary mouse button actions

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Touch Input Types

• Resistive Membrane
• Requires pressure to activate
• Some loss of display quality
• Capacitive touch screen
• Activated by close proximity
• Does not work when wearing gloves

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Touch Input - Uses

• No new interaction strategy to teach users
• Excellent for menu selection tasks
• Avoid using where a high degree of accuracy is
• required (example - graphics editing or cursor
• positioning tasks)
• Ideal for ATMs, Public Kiosks, Point of sale
• terminals

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Touch Screen Guidelines

• Avoid Double click operations
• Avoid tapping in the same location
• successively
• Avoid drag and drop operations
• Avoid extensive editing tasks
• Angle device at 30 - 45 degree angle
• Keep button sizes 26mm square with at
• least 10mm horizontal separation and
• 5mm vertical separation

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Touch Screen - Guidelines

• Provide appropriate feedback
• Tactile feedback
• Auditory feedback (beep tone at 820hz) when a
• valid area touched
• Not all users find auditory feedback useful
• Land-on vs. Lift-off activation
• Lift off more accurate but slower
• Land-on is less accurate but faster
• Keep target areas and guard regions large

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Remember

• Understand the principles of mobile usability
• UI models are essential for good mobile
• design implementations
• Validate actual usage assumptions
• Test and document new design patterns
• Embrace Standards! (J2ME, MIDP2, etc)