Seminar on input and output devices

SEMINAR PRESENTATION ON TOPIC: INPUT AND OUTPUT DEVICES BY OKWORI ODE FABIAN ADMISSION NUMBER (0910208054) DEPARTMENT OF INFORMATION TECHNOLOGY FACULTY OF SCIENCE

KEBBI STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ALIERO, PMB 1144 KEBBI STATE-NIGERIA IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF B.Sc. INFORMATION TECHNOLOGY

JUNE, 2013

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Introduction Do you ever wonder how information gets into your computer and comes out in a form you can use?  Input devices convert what we understand into what the computer can process.  Output devices convert what the computer has processed into a form that we can understand. What is Input? •

Any data or instructions used by a computer

 Input devices  Hardware  Keyboards  Pointing devices

 Scanning devices  Other devices  Translates data into a form that the computer can process

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Input devices are hardware used to translate words, sounds, images, and actions that people understand into a form that the computer can understand

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Input allows user to put their information into computer language

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Most common are keyboard (Key Term), mouse (Key Term), “light” pens (Key Term), and increasingly voice!

Keyboard Entry 2

 Keyboards  Traditional keyboards  Flexible keyboards  Ergonomic keyboards  Wireless keyboards  PDA keyboards Keyboard Entry Traditional Keyboard

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Keyboards come in a variety of designs •

Range from full-sized to miniature and from rigid to flexible

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Common types •

Traditional – full sized, rigid, rectangular keyboards that include function, navigational, and numeric keys

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Flexible – fold or roll up for easy packing or storage

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Ergonomic keyboards – similar to traditional •

Keyboard arrangement is not rectangular and a palm rest is provided 3

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Wireless – transmit input to the computer through the air

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PDA - miniature keyboards

Pointing Devices  Mice

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Mechanical

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Optical

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cordless or wireless

Three similar devices to mice  Trackball  Touch pads  Pointing stick

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Pointing Devices provide a comfortable interface that creates machine-readable data that can go directly to the CPU.

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Pointing devices mouse, joystick (Key Term), touch screen (Key Term), light pen (Key Term), and stylus (Key Term) 4

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A mouse incorporates a mouse pointer (Key Term) which usually appears in the shape of an arrow

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Some mice are also equipped with a wheel button (Key Term) that can be rotated to scroll through information

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Mouse types •

Mechanical mouse (Key Term) – traditional type; left/right button and mouse ball; most widely used and incorporates a mouse pad for use

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Optical mouse (Key Term) – has no moving parts

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Emits and senses light to detect mouse movement

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Can be used on any surface

Cordless mouse (Key Term) or wireless mouse (Key Term) – battery powered •

Uses radio waves or infrared light waves

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Trackball – also referred to as a roller ball (Key Term); controls the pointer by rotating a ball with your thumb

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Touch surfaces – also referred to as touch pads (Key Term); controls the pointer by moving and tapping your fingers on the surface of a pad

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Pointing stick – located in the middle of a keyboard; controls the pointer by directing the stick with your finger

Scanning Devices  Optical scanners  Flatbed scanners  Portable scanners  Card Readers  Magnetic card readers  Radio Frequency card readers

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Scanners move across text and images

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Scanning devices convert scanned data into a form the computer can process

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Types •

Optical – known as a scanner

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Recognizes light, dark, and colored areas that make up individual letters or images

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Types •

Flatbed – much like a copy machine

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Portable – typically a handheld device that slides across the image making direct contact. Mostly used by research students.

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Card Readers interpret encoded information that is stored on debit, credit, and identification cards

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Types •

Magnetic card reader (Key Term) – information is stored on a thin magnetic strip on the back of a card; is read when swiped through a magnetic card reader

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Radio frequency card reader – not as common but more convenient; card has a RFID (radio frequency identification) (Key Term) chip that is read when passed within a few inches of a card reader

Scanning Devices  Bar code readers  Handheld wand readers or platform scanners  Contain photoelectric cells that read bar codes  Character and mark recognition devices 6

 Magnetic ink character recognition (MICR)  Optical-character recognition (OCR)  Optical-mark recognition (OMR)

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Bar code readers or bar code scanners (Key Term)

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You see these devices at the grocery store

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Wand reader or platform scanner

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Reads bar codes or vertical zebra striped marks printed on product containers

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Products have a UPC (Universal Product Code) (Key Term)

Character and mark recognition devices are scanners that recognize special characters & marks •

MICR – used by banks to read those unusual numbers on the bottom of checks and deposit slips; read by a reader/sorter

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OCR – used in department stores to read retail price tags by reflecting light on the printed characters; read by OCR devices such as wand scanners

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OMR (also called mark sensing) – devices sense the presence or absence of marks, common for test scoring

Image Capturing Devices  Digital cameras  Images recorded digitally on a disk  Images can be downloaded to a computer  Digital video cameras  Records motion digitally  Can take still images as well 7

 Webcams  Specialized digital video cameras  Broadcast images over the Internet

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Imaging capturing devices create or capture original images •

Digital cameras – similar to traditional cameras except images are recorded digitally on disk or a camera’s memory

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Digital video cameras – records motion digitally on a disk or camera’s memory •

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Can take still photos as well

Webcams – also referred to as web cameras are specialized digital video cameras that capture images and send them to a computer to broadcast over the Internet/.

Audio-Input Devices.  Voice recognition systems  Use a microphone, a sound card, and special software  Users can operate computers and create documents using voice commands

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Audio input can take many forms, including the human voice and music

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Convert speech into digital code; most common device is the microphone; gaining in popularity are the portable digital voice recorders used with voice recognition systems

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Voice recognition systems 8

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Microphone, bundled with sound card and software

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Some voice recognition systems must be trained for user’s voice

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Some can translate from one language to another

What is Output?  Processed data or information  Types of output  Text  Graphics/Photos  Audio & video  Output devices  Monitors  Printers  Other Devices

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Converts machine-readable information into people-readable form

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Most common output types – text, graphics, photos, audio, and video

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The most widely used output devices are monitors, printer, and audio-output devices

Monitors  Known as screens or display screens  Output referred to as soft copy  Features 9

 Resolution/pixels  Dot pitch  Refresh rate  Size

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Standards indicate screen quality (resolution). Some monitors are used on the desktop, others are portable.

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Features – most important is clarity (Key Term) •

Resolution – one of the most important features; images are formed on a monitor by a series of dots or pixels (picture elements) (Key Term)

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Dot (pixel) pitch (Key Term) – the distance between each pixel; most newer monitors have a dot pitch of .31 mm (31/100th of a millimeter) or less

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Refresh rate – indicates how often a displayed image is updated or redrawn on the monitor; most monitors operate at a rate of 75 hertz which means that the monitor is redrawn 75 times each second; flickering indicates that the monitor rates are lower than 75 hertz

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Size – or viewable size is measured by the diagonal length of a monitor’s viewing area •

Common sizes are 15, 17, 19, and 21 inches

Monitors  Cathode-ray tube (CRT) monitors  Flat-panel monitors (LCD)  Require less power to operate  Portable and thinner than CRTs  Other monitors 10

 E-books  Data projectors  High-definition television (HDTV)

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Cathode-Ray Tubes – similar to television technology; are bulky

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Flat-Panel Monitors – or liquid crystal display (LCD) (Key Term) monitors

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Passive-matrix monitor (Key Term) or dual-scan monitors (Key Term) – images created by scanning the entire screen

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Active-matrix monitor (Key Term) or thin film transistor (TFT) monitors (Key Term) – each pixel is individually activated

Other Monitors •

eBook – also called e-book readers; handheld, book-sized devices that display text and graphics.; used to read newspapers, magazines, and entire books.

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Data projectors – devices connect to microcomputers and project computer output just as it would appear on a monitor.

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HDTV – merger of microcomputer and TV called PC/TV; output is digital so can freeze video sequences to create high-quality still images

Printers  Translates information that has been processed by the computer and present the information on paper.  Output referred to as hard copy  Features  Resolution  Color capability  Speed  Memory 11

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Printers translate information that has been processed by the computer and present the information on paper

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Output is called hard copy

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Features •

Resolution – measures the clarity of images produced •

Measured in dots-per-inch (dpi) (Key Term)

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Most printers use an average of 1200 dpi; the higher the dpi, the better the quality of image produced

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Color capability – more expensive to print in color; usually have the option to print in either color or b/w

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Speed – measured in the number of pages printed per minute •

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15-19 pages per minute is the average for a single color page (black); 13-15 pages per minute for color

Memory – used to store printing instructions and documents waiting to be printed

Printers  Ink-jet printer  Laser printer  Personal laser printers  Shared laser printers  Thermal printer  Other printers 12

 Dot-matrix printers  Plotters  Photo printers  Portable printers

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Three major types of printers: ink-jet, laser, and thermal; most people are familiar with these

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Inkjet printers spray ink at high speed onto the surface of paper. •

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Produce 17-19 pages/min of b/w and 13-15 of color output.

Laser printers – similar to technology used in photocopying machine; uses a laser light beam to produce images •

More expensive than ink jet printers

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Shared laser printers print over 50 pages/min.

Thermal printers – uses heat elements to produce images on heat sensitive paper •

Widely used with ATMs to print receipts.

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Used to produce high quality art work

Other Printers •

Dot-matrix – slow and not used much any more; poor quality but faster than some of newer printers •

Very noisy

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Inexpensive

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Plotters – special purpose for maps, images, architectural & engineering drawings

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Photo printers – designed to print photographs from digital cameras

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Portable printers – usually small/lightweight and designed to work with a notebook computers; may be ink-jet or laser printer that prints in either b/w or color

Audio-Output Devices  Translates audio information from the computer into sounds that people can understand  Common devices  Speakers  Headphones  Digital Music Players  iPod  iRiver

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These devices produce sounds for people

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Connected to a sound card in the system unit

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Voice output is quite common; creating voice output is not as difficult as recognizing and interpreting voice input

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Digital Music Players (also called digital media players (Key Term)) are specialized devices for storing, transferring, and playing audio files. Older players play MP3 files only. Newer players recognize other formats and also video.

Multifunctional Devices (MFD)  Many devices combine input and output capabilities and offer cost and space advantages  Fax machines  Internet telephones 14

 known as Internet telephony  IP telephony  and Voice-over IP (VoIP)

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Combination devices include fax machines also known as a facsimile (fax) transmission machine, multifunction devices, Internet telephones, and terminals

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Multifunction devices (MFD), can combine the capabilities of a scanner, printer, fax and copy machine

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Internet telephone – specialized input and output devices for receiving and sending voice communication

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Connect to the system unit through a USB port •

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Telephony (Key Term) – the transmission of telephone calls over computer networks •

Known as Voice over IP (VoIP) (Key Term)

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Uses Internet rather than traditional

Requires •

Internet telephone

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Internet

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Special service provider

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Sound card

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Special software

Terminal is an input and output device that connects to a mainframe or a host computer

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REFERENCES www.computerhope.com www.wikibook.org www.abcya.com http://www.igcseict.info http://www.britannica.com http://www.slideshare.net http://library.thinkquest.org •

http://tarlab.usu.edu/

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