CIS 524 discussion 7

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Computer Interaction and Design
CIS 524

Interaction Devices

Welcome to Computer Interaction and Design.

In this lesson we will learn about interaction devices.

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Topics

Keyboards and Keypads
Pointing Devices
Speech and Auditory Interfaces
Displays- Small and Large

The following topics will be covered in this lesson:

Keyboards and Keypads;

Pointing Devices;

Speech and Auditory Interfaces; and

Displays- Small and Large.

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Overview

Significant changes in the components the input and out put devices associated with computers

As there have been significant changes in the personal computer since the 1960s so have the components of the input and output devices associated with the computer. These changes have included items such as pointing devices undergoing hundreds of refinements to accommodate varied users and to maximize user performance. Such devices include DataGloves, and eye trackers.

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Keyboards and Keypads

QWERTY layout
1870 Christopher Latham Sholes
good mechanical design and a clever placement of the letters that slowed down the users enough that key jamming was infrequent
put frequently used letter pairs far apart, thereby increasing finger travel distances

Dvorak layout
1920
reduces finger travel distances by at least one order of magnitude
Acceptance has been slow despite the dedicated efforts of some devotees
it takes about 1 week of regular typing to make the switch, but most users have been unwilling to invest the effort

There are two important layouts to know with keyboards and keypads. The first is the QWERTY layout which was developed in 1870 by Christopher Latham Sholes. With its good mechanical design and a clever placement of the letters, it slowed down the users enough that key jamming was infrequent

but frequently used letter pairs were far apart, thereby increasing finger travel distances.

The second was the Dvorak layout developed in 1920 which reduces finger travel distances by at least one order of magnitude. Acceptance has been slow despite the dedicated efforts of some devotees. It takes about one week of regular typing to make the switch, but most users have been unwilling to invest the effort.

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Keyboard and Keypads, continued

ABCDE style
Additional keyboard issues
Keyboards and keypads for small devices
Characteristics of keys

Another keyboard layout is the ABCDE style which is comprised of the twenty six letters of the alphabet laid out in alphabetical order in which non-typists will find it easier to locate the keys.

Additionally keyboard issues were widely known. The IBM PC keyboard was widely criticized because of the placement of a few keys and there was a backslash key where most typists expect SHIFT key to include the placement of several special characters near the ENTER key . There were also issues with the number pad layout as well as wrist and hand placement.

The keys themselves have very special characteristics such has one half inch square keys, one quarter inch spacing between keys, slight concave surface, matte finish to reduce glare and finger slippage. The keys also require forty to one hundred twenty five grams of force to activate them. Keys also have a three to five millimeters displacement. Some keys have tactile and audible feedback. Certain keys should also be larger such as the ENTER, SHIFT, and CONTROL keys. Some keys require a state indicator, such as lowered position or light indicator such as CAPS LOCK. Key labels should be large, meaningful, permanent, and some home keys may have additional features, such as a deeper cavity or small raised dot, to help user locate their fingers properly.

In addition to the other keys we discussed, there are cursor movement keys which provide navigation up, down, left, and right. Other movements can be performed with other keys, such as TAB, ENTER, HOME, and so on. With function keys, users must either remember each key's function, identify them from the screen's display, or use a template over the keys in order to identify them properly.

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Keyboard and Keypads, continued

Keyboard and keypads for small devices
Wireless or foldable keyboards
Virtual keyboards
Cloth keyboards
Soft keys
Pens and touchscreens

Special consideration has to be given when thinking about keyboard and keypads for small devices. Currently there are wireless, foldable, virtual, cloth, soft key, pens, and touchscreens that are currently on the market. These devices should be paired accordingly to maximize its use.

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Check Your Understanding

Pointing Devices

Pointing devices are applicable in seven types of interaction tasks.

Select

Position

Orient

Path

Quantify

Gesture

text

Pointing devices are applicable in seven types of interaction tasks. The first type is Select which is where the user chooses from a set of items. This is used for traditional menu selection, identification of a file in a directory, or marking of a part in an automobile design.

The second type is Position which is where the user chooses a point in a one-, two-, three-, or higher-dimensional space used to create a drawing, to place a new window, or to drag a block of text in a figure.

The third type is Orient which is where the user chooses a direction in a two-, three-, or higher-dimensional space. Direction may simply rotate a symbol on the screen, indicate a direction of motion for a space ship, or control the operation of a robot arm.

The fourth type is Path which is where the user rapidly performs a series of position and orient operations. This may be realized as a curving line in a drawing program, the instructions for a cloth cutting machine, or the route on a map.

The fifth type is quantify which is where the user specifies a numeric value. This is usually a one-dimensional selection of integers or real values to set parameters, such as the page number in a document, the velocity of a ship, or the amplitude of a sound.

The sixth type is gesture. Here users indicate an action to perform by executing a simple gesture, such as a swipe motion to the left or the right to turn a page forward or backward.

The last type is Text. This is where the user enters, moves, and edits text in a two-dimensional space. The pointing device indicates the location of an insertion, deletion, or change. More elaborate tasks include centering; margin setting; font sizes; highlighting, such as boldface or underscore; and page layout.

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Direct Control Pointing Devices

Lightpen
Touchscreen

An example of a direct control pointing device is a lightpen. This device enables users to point to a spot on a screen and to perform a select, position, or other tasks. It allows direct control by pointing to a spot on the display. It incorporates a button for the user to press when the cursor is resting on the desired spot on the screen. Additionally the lightpen has three disadvantages: First, users' hands obscure part of the screen. Second, users have to remove their hands from the keyboard. And lastly, users have to pick up the lightpen.

Another direct control pointing device is a touchscreen. This allows direct control touches on the screen using a finger. The early designs were rightly criticized for causing fatigue, hand-obscuring-the-screen, hand-off-keyboard, imprecise pointing, and the eventual smudging of the display. The users touch the surface then see a cursor that they can drag around on the display. When the users are satisfied with the position, they lift their fingers off the display to activate.

Tablet PCs and mobile devices generally have a stylus with them. The user gestures and the device has handwriting recognition.

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Indirect Pointing Devices

In this slide we discuss indirect pointing devices such as the mouse, trackball, joystick, graphics tablet, and touch pad. With the mouse the hand rests in a comfortable position; buttons on the mouse are easily pressed, even long motions can be rapid, and positioning can be precise. The trackball is usually implemented as a rotating ball one to six inches in diameter that moves a cursor. The joystick is appealing for tracking purposes. The graphics tablet is a touch-sensitive surface separate from the screen. The touchpad is a built-in near the keyboard which offers the convenience and precision of a touchscreen while keeping the user's hand off the display surface.

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Comparison of Pointing Devices

When comparing pointing devices it is important to look at the human factor variables. These variables are speed of motion for short and long distances, accuracy of positioning, error rates, learning time, and user satisfaction. Other variables to consider are cost, durability, space requirements, weight, left- versus right-hand use, likelihood to cause repetitive-strain injury, and compatibility with other systems.

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Speech and Auditory Interfaces

Speech recognition still does not match the fantasy of science fiction

Speech recognition still does not match the fantasy of science fiction. These devices do not meet the demands of user's working memory. Background noise is problematic and variations in user speech performance impacts effectiveness. These devices are most useful in specific applications, such as to benefit handicapped users .

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Speech and Auditory Interfaces, continued

With speech and auditory interfaces there is discrete word recognition. This is when the devices recognize individual words spoken by a specific person. This can work with ninety- to ninety eight-percent reliability for twenty to two hundred word vocabularies. Speaker-dependent training, in which the user repeats the full vocabulary once or twice is needed. Speaker-independent systems are beginning to be reliable enough for certain commercial applications. They have been successful in enabling bedridden, paralyzed, or otherwise disabled people. They are also useful in applications with at least one of the following conditions: One, speaker's hands are occupied; Two, mobility is required; Three, speaker's eyes are occupied; And four, harsh or cramped conditions preclude use of keyboard.

One issue is that continuous speech recognition is not generally available. This is because of the difficulty in recognizing boundaries between spoken words, and normal speech patterns. With speech store and forward, voice mail users can receive messages, replay messages, reply to callers, forward messages to other users, delete messages, and archive messages. These systems are low cost and reliable.

Voice information systems are low cost systems that store speech commonly used to provide information about tourist sites, government services, and after-hours messages for organizations.

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Displays- Small and Large

Usage characteristics distinguish displays:
Portability
Privacy
Saliency
Ubiquity
Simultaneity

There are five known unique usage characteristics to distinguish displays. The five characteristics are portability, privacy, saliency, ubiquity, and simultaneity. In terms of display technology there are different options. Monochrome displays are adequate, and are attractive because of their lower cost. Raster-scan cathode ray tubes have almost disappeared and been replaced by LCD displays. LCD displays are thin, light weight, and consume less electricity. Plasma displays are also popular. They are similar in size to LCD’s but consume more electricity. Light emitting diodes or LEDs are now being used in man large public displays.

Some products can even attain paper like resolution by using electronic ink technology. Examples of this type of technology can be seen in many popular e-readers like the Amazon Kindle and Barnes and Noble’s Nook.

Tiny projectors are also becoming available. They will soon be able to project color images on the wall from mobile devices.

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Check Your Understanding

Displays- Small and Large, continued

Large displays
Heads up and helmet mounted displays

Now let’s discuss large displays and heads up displays.

There are three types of large displays. The first type is informational wall displays which provide shared views to users standing far away from the display. The next type is interactive wall displays. These allow users to walk up to the display and interleave interaction and discussion among participants. The last type of large displays is multiple desktop displays. Users can connect these to their computers to have a larger number of windows and documents visible at the same time.

A heads-up display can for instance, project information on a partially silvered widescreen of an airplane or car. A helmet/head mounted display moves the image with the user and has 3D images. These can be of use in environments such as gaming, and tactical operations such as controlling unmanned vehicles.

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Mobile Device Displays

Currently mobile devices are used for brief tasks, except for game playing. They are optimized for repetitive tasks. Most applications are custom designed to take advantage of every pixel.

Web browsing can be difficult on mobile device displays. However it is okay for linear reading, but making comparisons can be difficult.

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Summary

Keyboards and Keypads
Pointing Devices
Speech and Auditory Interfaces
Displays- Small and Large

We have reached the end of this lesson. Let’s take a look at what we’ve covered.

In the begging we discussed the significant changes in the personal computer.

Then we explored keyboards and keypads. The two most widely known keyboard layouts are the QWERTY and Dvorak layout.

Next we discussed pointing devices. Here we learned about the different types of pointing devices. We also learned about the seven types of interaction tasks.

We also learned about speech and auditory interfaces.

Finally we learned about displays. We covered the different types of display technologies. As well as large displays and heads up and helmet mounted displays.

This completes the lesson.

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