Input And Output

Hardware chapter (6)

TEACHER : SIR ZEESHAN ABBAS

Teacher: SIR ZEESHAN ABBAS

Group Members:UZAIR JAVED1421-315313Haris 1421-315224Muhammad umer 1421-315309

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Input DevicesKeyboard.MouseMicrophoneDigital CameraScanner

INPUT HARWARE OPTIONSKEY BOARD

It is an input device used to enter data in computer.

Keyboard has many different types of keys,

Function keys (F1,F2 & so on)Numeric Keys (1,2,……….)

Symbols (@,&,……….)Alphanumeric keys (A,a,B,b,…..)

Cursor control (Tab, Enter,…..)

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The KeyboardThe most commonly used input device is the keyboard on which data is entered by manually keying in or typing certain keys. A keyboard typically has 101 or 105 keys.

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The MouseIs a pointing device which is used to control the movement of a mouse pointer on the screen to make selections from the screen. A mouse has one to five buttons. The bottom of the mouse is flat and contains a mechanism that detects movement of the mouse.

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Light pen•A light pen is a small ‘pen-shaped’ wand, which contains light sensors. •It is used to choose objects or commands on the screen either by pressing it against the surface of the screen or by pressing a small switch on its side. •A signal is sent to the computer, which then works out the light pen’s exact location on the screen. •The advantage of a light pen is that it doesn’t need a special screen or screen coating.

Whenever a key is pressed. It will be first converted in to binary codes. then the desired function will be performed. Keyboard is an advanced version of type writer.

KEY BOARD

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Input DevicesUsed by a person to communicate to a computer.

Person to computer

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Keyboard

The keyboard allows the computer user to enter words, numbers, punctuation, symbols, and special function commands into the computer’s memory.

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Pointing devices - direct

Touch screens

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Touch screens

Often used for applications with occasional use, for example

Bank ATMs, Information Kiosks, etc. No extra hardware - used for input and

for output Can be precise to 1 pixel Good for menu choice - not so good for

other functions Intuitive to use

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Touch screens BUT

Tiring if at wrong angle (needs to be 30-45% from horizontal)

Get greasy, jammy Finger can obscure screen Alternative - use stylus to touch screen, or

lightpen

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Indirect Pointing Devices Need more cognitive processing than

direct methods, but can be more efficient

mouse tracker ball track point touchpad…

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Indirect pointing devices - other

Joystick The main use of a joystick

is to play computer games by controlling the way that something moves on the screen.

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Microphones - Speech Recognition• Use a microphone to talk to your

computer • Add a sound card to your computer• Sound card digitizes audio

input into 0/1s • A speech recognition program can process the input and convert it into machine-recognized commands or input

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Audio Input: Speech Recognition

Speech recognition is a type of input in which the computer recognizes words spoken into a microphone.

Special software and a microphone are required.

Latest technology uses continuous speech recognition where the user does not have to pause between words.

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Microphones - Speech Recognition

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Digital cameraA digital camera can store many more pictures than an ordinary camera. Pictures taken using a digital camera are stored inside its memory and can be transferred to a computer by connecting the camera to it. A digital camera takes pictures by converting the light passing through the lens at the front into a digital image.

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ScannerA scanner can be used to input pictures and text into a computer. There are two main types of scanner; Hand-held and Flat-bed.

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Bar codes

•A bar code is a set of lines of different thicknesses that represent a number

•Bar Code Readers are used to input data from bar codes. Most products in shops have bar codes on them

•Bar code readers work by shining a beam of light on the lines that make up the bar code and detecting the amount of light that is reflected back

Bar Codes Optical Mark Recognition Optical Character Recognition Magnetic Ink Character Recognition

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Indirect pointing devices - other

Tracker ball, trackpad, trackpoint

Less space on desktop

Good in moving environments, e.g. car, train

OTHER INPUT DEVICES

Output hardware falls into three categories

1. Permanent output2. Temporary output3. Action output

OUTPUT HARWARE SOLUTION • Output hardware falls into three categories

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Output DevicesDisplays information from the computer to a person.

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and output… textual information visual images - photos, diagrams, icons moving images sounds - music, voice Etc..

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2. Output Types Text output Graphics output Video output Audio output

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Output Devices Monitors Printers Speakers Data Projectors

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Monitors

A monitor is a peripheral device which displays computer output on a screen.

Screen output is referred to as soft copy. Types of monitors:

◦ Cathode-ray tube (CRT)◦ Liquid Crystal Display (LCD or flat-pan

el)

CRT LCD

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Monitors CRT

◦cathode ray tube electron gun shoots a stream of electrons at a

specially phosphor-coated screen on impact, the phosphor flares up for a fraction of

a second electron gun sweeps across the screen many

times a second LCD

◦ liquid crystal display one of several types of “flat-panel” displays forms output by solidifying crystals and

“backlighting” the image with a light source◦TV sets are CRTs and many desktop

monitors use this technology ◦LCD is primarily used for laptops and other

portable devices

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Video Display Terminology Pixel

◦ picture element (smallest unit of an image, basically a single dot on the screen)

Resolution ◦ number of pixels in the image ◦ Common resolution size is

1024x768 ◦ Refresh rate

how often a CRT’s electron gun rescans

LCD displays do not use an electron gun, so do not perform refreshing

The CRT electron gun “shoots” 3 electrons at the screen representing the amount of red, green and blue for the pixel

Permanent Output

PrintersPlotters

• Computer processed information in the form of printed documents and microfilm a vast selection of hardware is available for its production.

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Output Devices: Engaging our Senses

Output devices are peripheral devices that enable us to view or hear the computer’s processed data.◦ Visual output – Text, graphics, and video◦ Audio output – Sounds, music, and

synthesized speech

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Printers A printer is a

peripheral device that produces a physical copy or hard copy of the computer’s output.

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Inkjet Laser

Types of Printers

Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper

Letter-quality printouts Cost of printer is

inexpensive but ink is costly

Laser printer works like a copier

Quality determined by dots per inch (dpi) produced

Color printers available Expensive initial costs but

cheaper to operate per page

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Plotter

A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.

It is used in engineering, drafting, map making, and seismology.

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Summary• Introduction• Input Devices

–Keyboard,mouse,joystick,scanners,digital camera, bar code reader, touch Sreeen,Speech input device (microphone)

• Output Devices–Monitor , Speaker, Printers ( different

types)

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Audio Output: Sound Cards and Speakers

Audio output is the ability of the computer to output sound.

Two components are needed:◦ Sound card – Plays contents of digitized recordings◦ Speakers – Attach to sound card

Printers It gives hard copy to the organization for the

routine business Correspondence, billing and accounting

information. For example Architects use to computer budget Types of printer Impact printer Desk jet dot matrix Non impact printers

Plotters It gives out in the form of graphs, maps,

charts and drawings.For exampleo artists use plotters for the different

sketches.Types of plotters Flatbed plotter Drum plotter

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Printers

Ink Jet Printer◦ least expensive, color, slower with a higher per

page cost than laser printers Laser Printer

◦ More expensive, faster, lower per page cost than ink jet,

Temporary Output• Video display and audio responses serve as effective, yet temporary, output inapplications that do not require permanent output.

• Video Display Output -CRT Monitor - Flat screen • Speech Synthesizers

PERIPHERAL DESIGN AND SAFETY

Some particular health concerns for users have arisen due to increased use of input and output peripherals in the past two decades. when people used only typewriters and pens for business paperwork, there were always breaks in actions

PERIPHERAL DESIGN AND SAFETY

Some particular health concerns for users have arisen due to increased use of input and output peripherals in the past two decades. when people used only typewriters and pens for business paperwork, there were always breaks in actions

EXAMPLE the typewriter carriage had to be returned

at the end of each line, paper needed to be changed, and errors had to be manually corrected .with the advent of computers especially word processing programs in

What is RSI? Repetitive Strain Injuries occur from

repeated physical movements doing damage to tendons, nerves, muscles, and other soft body tissues.

Another name for the condition is Cumulative Trauma Disorder.

,it is possible for a person to spend several hours typing at a keyboard and looking at the monitor with little change in hand and body position .it was not long before workers were complaining about pain in their wrists and hands, back and neck aches, and headaches due to eye strain

What is RSI? Repetitive Strain Injuries occur from

repeated physical movements doing damage to tendons, nerves, muscles, and other soft body tissues.

Another name for the condition is Cumulative Trauma Disorder.

What is RSI? Repetitive Strain Injury (RSI)

◦ is pain or nerve problems in upper extremity (hands, arms, or shoulders)

◦ can also include neck and back◦ is a soft tissue disease (muscles and nerves)◦ is an overuse syndrome

Symptoms:◦ burning, numbness, tingling, pins-and-needles◦ dull aching OR specific, intense pain

Controversial:◦ many deny it exists◦ sufferers receive little support from employers

What are the Symptoms? Tightness, discomfort, stiffness, or pain in

the hands, wrists, fingers, forearms, or elbows.

Tingling, coldness, or numbness in the hands.

Clumsiness or loss of strength and coordination in the hands.

Pain that wakes you up at night. Feeling a need to massage your hands,

wrists, and arms.

Some Specifics

Don’t rest the wrist

on anything

while typing.

You are a computer athleteA dangerous occupation:

This is also dangerous:

As a typical computer user, you “walk” several miles each day on your fingertips

(250 keystrokes / min) * (2 in / keystroke) * 4 hours = 2 miles

How Can It Be Prevented?

Ensure that the operator has a comfortable sitting position sufficiently flexible to reach, use, and observe the display screen, keyboard, and document.

Provide posture support for the back, arms, legs, and feet, and adjustable display screens and keyboards.

Ensure that the Video Display Terminals (VDT) tables or desk are vertically adjustable to allow for operator adjustment of the screen and keyboard.

Ensure proper chair height and support to the lower region of the back.

Ensure that document holders are used to allow the operator to position and view material without straining the eyes or neck, shoulder, and back muscles.

What causes RSI?

Cantilevers

stress

Bad posture

ulnar deviation dorsiflexion

pronation

slouching

Since monitors were introduced in late 1970s,people have been concerned about the effects of extremely low frequency (ELF) emissions from these screens

Low Frequency emission

. Rumors of miscarriages and brain tumors are caused by VDT emissions have yet to be substantiated by medical researchers .at the very least , many users find that the glare from the screen causes eyestrain and headaches.

What is Ergonomics? ERGO=“work”

NOMICS=“rules” or “laws”

Ergonomics literally means “the laws of work”

Ergonomics is the science (and art) of fitting the work environment of the employee. By improving the match between the work environment and the employee, you can expect improved employee comfort, reduce changes for occupational injuries, improved productivity, and improved employee job satisfaction.

The Ergonomics

What is Ergonomics?

OSHA defines ergonomics as the science of “designing the job to fit the worker, instead of forcing the worker to fit the job.”

Ergonomics is way to work smarter—Not harder by designing of tools, equipment, workstations and tasks to fit the job to the worker.—NOT the worker to the job.

Layout/type of controls and displays. Lighting and temperature Process (heights, reaches and weight)

Ergonomics is the science (and art) of fitting the work environment of the employee. By improving the match between the work environment and the employee, you can expect improved employee comfort, reduce changes for occupational injuries, improved productivity, and improved employee job satisfaction.

The Ergonomics

The goal of ergonomic is to design jobs to fit people. Something is ergonomically design, if its optimized to fit people. this means taking account of differences such as size, strength and ability to handle information for a wide range of users. Then the tasks, The workplace and the tools are designed around these differences.

What is Ergonomics?

Ideally, ergonomics: ◦ Makes the job safer by preventing injury

and illness◦ Makes the job easier by adjusting the job

to the worker◦ Makes the job more pleasant by reducing

physical and mental stress◦ Saves money $$$

Awkward posture: If a job tasks looks uncomfortable, it probably is and this increases the chances for injuries. whenever possible, strive to arrange the work environment of work processes to allow employees to work from comfortable, neutral posture, Excessive bending, reaching awkward neck, back, and arm positions should be eliminated.

Ergonomics

Is concerned with reduction of one or more of the following risk factors.

Ergonomic Factors Two Categories of Ergonomic

Factors

1.Environmental

2.Physical

Environmental Factors

Environmental factors may affect:◦ Hearing◦ Vision◦ General comfort and health

Environmental Factors

Some examples of ergonomic environmental problems are:◦ Sick Building Syndrome◦ Excessive noise◦ Improper lighting◦ Temperature extremes

Environmental Factors

What are some of the environmental factors that might effect your work area?

Physical Stressors Physical stressors place pressure or stress

on parts of the body:◦ Joints, muscles, nerves, tendons, bones

Sometimes these injuries are referred to as “Cumulative Trauma Disorders” (CTDs) or “Repetitive Strain Injuries” (RSIs)

Cumulative Trauma Disorders (CTDs)

Cumulative = occurring gradually over a period of weeks, months, or years

Trauma = bodily injury to nerves, tissues, tendons, or joints

Disorders = physical ailments or abnormal conditions

Cumulative Trauma Disorders Examples of Cumulative Trauma

Disorders include: Carpal Tunnel Syndrome Epicondylitis Tenosynovitis Bursitis

Risk Factors The main risk factors for office-related

CTDs are: Repetition Awkward positions or posture Excessive pressure or force

Another risk factor for CTDs would be: Vibration

Risk Factors: Repetition The majority of CTDs are caused by

repetitive motions that would not result in injury if only performed once. Thousands of keystrokes typing Hours of filing, day after day Stamping dozens of papers Frequent lifting Repeated motions with computer mouse