HCI Chapter 2-4: Computer Interaction Devices

Positioning, Pointing, and Drawing

• Handheld pointing devices: mouse, touchpad, trackballs, joysticks, touch screens, tablets, and eyegaze
• Mouse characteristics: planar movement and buttons (usually 1-3)
• Mouse located on desktop, requires physical space, no arm fatigue, and is an indirect manipulation device

The Mouse

• Relative movement is detectable, moves screen cursor, and is oriented in (x, y) plane
• Methods for detecting motion: mechanical and optical
• Mechanical method: ball on underside of mouse turns, rotating orthogonal potentiometers
• Optical method: light emitting diode on underside of mouse, detects fluctuating alterations in reflected light intensity
• Foot-operated mouse experiments exist, but are not common

Touchpad

• Small touch-sensitive tablets used mainly in laptop computers
• Acceleration settings are important: fast stroke for lots of pixels per inch moved, initial movement to the target
• Slow stroke for accurate positioning

Trackball and Thumbwheels

• Trackball: ball rotated inside static housing, indirect device, fairly accurate, separate buttons for picking
• Thumbwheels: for accurate CAD, two dials for X-Y cursor position; for fast scrolling, single dial on mouse

Joystick and Keyboard Nipple

• Joystick: indirect, pressure of stick equals velocity of movement, buttons for selection
• Keyboard nipple: miniature joystick in the middle of the keyboard for laptop computers

Touch-sensitive Screen

• Detects the presence of finger or stylus on the screen using interrupting light beams, capacitance changes, or ultrasonic reflections
• Direct pointing device, advantages: fast, no specialized pointer needed, suitable for hostile environments
• Disadvantages: finger can mark screen, imprecise, difficult to select small regions or perform accurate drawing

Stylus and Light Pen

• Stylus: small pen-like pointer to draw directly on screen, uses touch-sensitive surface or magnetic detection
• Light Pen: now rarely used, uses light from screen to detect location
• Both: direct, obvious to use, but can obscure screen

Digitizing Tablet

• Mouse-like device with cross hairs, used on special surface, very accurate, used for digitizing maps

Positioning, Pointing, and Drawing

• Handheld pointing devices: mouse, touchpad, trackballs, joysticks, touch screens, tablets, and eyegaze
• Mouse characteristics: planar movement and buttons (usually 1-3)
• Mouse located on desktop, requires physical space, no arm fatigue, and is an indirect manipulation device

The Mouse

• Relative movement is detectable, moves screen cursor, and is oriented in (x, y) plane
• Methods for detecting motion: mechanical and optical
• Mechanical method: ball on underside of mouse turns, rotating orthogonal potentiometers
• Optical method: light emitting diode on underside of mouse, detects fluctuating alterations in reflected light intensity
• Foot-operated mouse experiments exist, but are not common

Touchpad

• Small touch-sensitive tablets used mainly in laptop computers
• Acceleration settings are important: fast stroke for lots of pixels per inch moved, initial movement to the target
• Slow stroke for accurate positioning

Trackball and Thumbwheels

• Trackball: ball rotated inside static housing, indirect device, fairly accurate, separate buttons for picking
• Thumbwheels: for accurate CAD, two dials for X-Y cursor position; for fast scrolling, single dial on mouse

Joystick and Keyboard Nipple

• Joystick: indirect, pressure of stick equals velocity of movement, buttons for selection
• Keyboard nipple: miniature joystick in the middle of the keyboard for laptop computers

Touch-sensitive Screen

• Detects the presence of finger or stylus on the screen using interrupting light beams, capacitance changes, or ultrasonic reflections
• Direct pointing device, advantages: fast, no specialized pointer needed, suitable for hostile environments
• Disadvantages: finger can mark screen, imprecise, difficult to select small regions or perform accurate drawing

Stylus and Light Pen

• Stylus: small pen-like pointer to draw directly on screen, uses touch-sensitive surface or magnetic detection
• Light Pen: now rarely used, uses light from screen to detect location
• Both: direct, obvious to use, but can obscure screen

Digitizing Tablet

• Mouse-like device with cross hairs, used on special surface, very accurate, used for digitizing maps

The Computer

• A computer system consists of various elements that affect interaction, including input devices, output devices, virtual reality, physical interaction, paper, memory, and processing.

Interacting with Computers

• To understand human-computer interaction, it's essential to understand what computers can do, including their devices, paper, sensors, memory, processing, and networks.

A Typical Computer System

• A typical computer system consists of an screen, keyboard, and mouse/trackpad, with variations such as desktop, laptop, and PDA.
• The devices used dictate the styles of interaction that the system supports.

Prevalence of Computers

• Computers are ubiquitous, with many devices in our homes and pockets, including PDAs, PCs, laptops, phones, cameras, TVs, and more.

Interactivity

• Long ago, computing was based on batch processing, but now most computing is interactive, with rapid feedback and user control.
• Interactivity allows users to do rather than think.

Richer Interaction

• Modern computing involves richer interaction, with sensors and devices everywhere.

Text Entry Devices

• Text entry devices include keyboards, chord keyboards, phone pads, and handwriting/speech recognition devices.

Keyboards

• Keyboards are the most common text input device, allowing rapid entry of text by experienced users.
• Keyboards have a standardized layout, such as QWERTY, but alternative designs are available.

QWERTY Layout

• The QWERTY layout is not optimal for typing, as it was designed to prevent typewriter jamming.
• Alternative designs, such as Dvorak, offer faster typing and reduced fatigue, but are not widely adopted due to the large social base of QWERTY typists.

Alternative Keyboard Layouts

• Alternative layouts, such as alphabetic and Dvorak, offer improved typing speed and reduced fatigue.
• Special keyboards, such as those designed for single-handed use or to reduce fatigue, are also available.

Chord Keyboards

• Chord keyboards have a few keys and use combinations of keypresses to type letters.
• They are compact, easy to learn, and fast, but may cause fatigue and face social resistance.

Phone Pad and T9 Entry

• Phone pads and T9 entry use numeric keys with multiple presses to type letters.
• T9 predictive entry uses a dictionary to guess the correct word, allowing fast typing.

Handwriting Recognition

• Handwriting recognition allows text input using a pen and a digitizing tablet.
• Technical problems include capturing useful information, segmenting joined up writing, and interpreting individual letters.
• Handwriting recognition is used in PDAs and tablet computers.

The Computer

• A computer system consists of various elements that affect interaction, including input devices, output devices, virtual reality, physical interaction, paper, memory, and processing.

Interacting with Computers

• To understand human-computer interaction, it's essential to understand what computers can do, including their devices, paper, sensors, memory, processing, and networks.

A Typical Computer System

• A typical computer system consists of an screen, keyboard, and mouse/trackpad, with variations such as desktop, laptop, and PDA.
• The devices used dictate the styles of interaction that the system supports.

Prevalence of Computers

• Computers are ubiquitous, with many devices in our homes and pockets, including PDAs, PCs, laptops, phones, cameras, TVs, and more.

Interactivity

• Long ago, computing was based on batch processing, but now most computing is interactive, with rapid feedback and user control.
• Interactivity allows users to do rather than think.

Richer Interaction

• Modern computing involves richer interaction, with sensors and devices everywhere.

Text Entry Devices

• Text entry devices include keyboards, chord keyboards, phone pads, and handwriting/speech recognition devices.

Keyboards

• Keyboards are the most common text input device, allowing rapid entry of text by experienced users.
• Keyboards have a standardized layout, such as QWERTY, but alternative designs are available.

QWERTY Layout

• The QWERTY layout is not optimal for typing, as it was designed to prevent typewriter jamming.
• Alternative designs, such as Dvorak, offer faster typing and reduced fatigue, but are not widely adopted due to the large social base of QWERTY typists.

Alternative Keyboard Layouts

• Alternative layouts, such as alphabetic and Dvorak, offer improved typing speed and reduced fatigue.
• Special keyboards, such as those designed for single-handed use or to reduce fatigue, are also available.

Chord Keyboards

• Chord keyboards have a few keys and use combinations of keypresses to type letters.
• They are compact, easy to learn, and fast, but may cause fatigue and face social resistance.

Phone Pad and T9 Entry

• Phone pads and T9 entry use numeric keys with multiple presses to type letters.
• T9 predictive entry uses a dictionary to guess the correct word, allowing fast typing.

Handwriting Recognition

• Handwriting recognition allows text input using a pen and a digitizing tablet.
• Technical problems include capturing useful information, segmenting joined up writing, and interpreting individual letters.
• Handwriting recognition is used in PDAs and tablet computers.

System Behavior

• System behavior describes what a system does, without explaining how it does it.
• It includes a system sequence diagram as part of its description.

System Sequence Diagram

• A system sequence diagram is a fast and easily created artifact.
• It illustrates input and output events related to the systems under discussion.