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Input

Lecture 5

What is Input?

Input is any data and instructions entered into the computer

What is Input?

Instructions can be entered into the computer in the form of programs, commands, and user responses

A program is a series of instructions that tells a computer what to do and how to do it.A command is an instruction that causes a program to perform a specific actionA user response is an instruction a user issues by replying to a question displayed by a program.

Input DevicesHardware component that allows users to enter and data and instructions into a computer.

KeyboardPointing Devices (Mouse, Trackball, touchpad etc)Controllers for gaming and media playersVoice InputDigital CamerasVideo InputScanners and Reading devicesTerminalsBiometric input

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Keyboard Keyboard

Most desk top computers haveBetween 101-105 keysNumeric keypadFunction keysArrow keysCtrl, Alt and Additional keysWindows key – displays start menuApplication key – displays short cut menuToggle keys

Keyboard

Insertion PointBlinking vertical bar that indicates where

next character you type will be displayedConnections

Wired Keyboards – USB PortWireless Keyboards – Bluetooth (receiver), IrDA

Keyboards on mobile computers and devices are small and/or have fewer keys.

Pointing DevicesInput device that allows the user to control the pointer on

the screen.Mouse• fits under the palm of your hand comfortably• Can be wired or wireless

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Other Pointing Devices

TrackballStationary pointing device with a ball on its top or side.Also has buttons that work like mouse buttons.

Other Pointing Devices

TouchpadA small, flat, rectangular pointing device that is sensitive to pressure and motion.

Pointing StickPressure sensitive pointing device, positioned between keys on a keyboard.

Other Pointing Devices

Light PenHandheldDetect presence of light

Touch ScreenTouch sensitive display device

Pen Input Stylus is a small metal or plastic pressure sensitive penDigital Pen are either pressure sensitive or have a built-in digital camera.

Other Pointing Devices

Graphic tablet

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Controllers for Gaming and Media Players

Video games and computer games use game controllers as input devices to direct movement and actions of on screen objects.GamepadsJoysticks and wheelsLight GunsDance padsTouch sensitive pad

Voice Input

Process of entering input by speaking into a microphone

Voice over IP enables users to speak to other users over the internetVoice Recognition is computer’s capability of distinguishing spoken words.Audio Input – entering any sound in the computerMIDI devices such as electrical piano using the MIDI port.Connect to sound card on the computer.

PDA, Tablet PCs

Primary input: stylus

Built-in mini keyboard

Portable Keyboard

Built in cameras

Scanners can be attached

Built in microphones

Pressure sensitive digital pen

Removable Keyboard

Docking station- external device, contains power connections and connection to peripherals

Digital Cameras

Take pictures and store photographed images digitally

Internal flash memory to store imagesAdditional storage media: flash memory cardConnect through USB port/FireWire port of computer

Camera QualityResolution: number of horizontal and vertical pixels in a display device

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Digital Cameras

oSharpness and clarity of imageoThe higher the resolution, the better the image quality, but the more expensive the cameraoPixel (picture element) is single point in electronic image

oGreater the number of pixels, the better the image quality

Video Input

Process of entering full motion images into the computerVideo Capture card is an adapter card that converts analog signals to digital signals that a computer can useDigital Video camera records video as digital signalsPC video cameras -Web Cameras – displays output on a webpageVideo Conferencing

Scanner and Reading Devices

ScannerDevice that captures data from a source documentOptical Scanner is a light sensing input that reads printed text and graphics

• Flatbed scanner, • Pen, • Sheet-fed,• Drum

Flatbed

Scanner and Reading Devices

Bar Code ReadersReading device that uses laser beams to read bar codesBar code represents data of manufacturer and item

RFID ReadersRadio frequency identification uses radio signals to communicate with a tagTag contains a memory and antenna, embedded in glass, labels cardsRFID reader reads information via radio signals

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Scanner and Reading Devices

Magnetic Stripe Card readersReads the magnetic strip on the back of the cardsStores information about name, account number, expiration date etcPOS terminals

Data collection devicesObtains data directly at the location where the transaction or event takes placeWirelessly transmits data

Terminal

Consists of a keyboard, a monitor, a video card, and a memory

Dumb terminal, smart terminal, special-purpose terminalSmart terminal has a processor, performs some functionsSpecial purpose – perform specific tasks

• Point of Sale Terminals• Automatic Teller Machines

Biometric Input

Biometric is the technology of authenticating person’s identity by verifying a personal characteristics

Biometric identifier – fingerprints, hand geometry, facial features, voice, signatures, eye patternBiometric device translates the personal characteristics into a digital codeCompares the code with the stored codeFingerprint Scanner

Biometric Input

Face Recognition SystemsCaptures live face imageLaw enforcement, surveillance systems, airports

Hand Geometry SystemsVerify student's identity, day care centers

Voice verification SystemsUsed as time and attendance devices or access to sensitive files

Iris Recognition Systems/Retinal ScannersGovernment security orgs, military

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Putting It All Together

Recommended input devices for small office/home office users:

• Enhanced keyboard • Mouse• Stylus and portable keyboard for PDA or

smart phone, or digital pen for Tablet PC• 36-bit 600 × 1200 ppi color scanner• 2-megapixel digital camera• Headset that includes a microphone• PC video camera Small Office/

Home Office (SOHO)

Putting It All Together

Recommended input devices for mobile users

• Wireless mouse for notebook computer• Trackball, touchpad, or pointing stick on

notebook computer• Stylus and portable keyboard for PDA or

smart phone, or digital pen for Tablet PC• 2- or 3-megapixel digital camera• Headset that includes a microphone• Fingerprint scanner for notebook

computerMobile

Putting It All Together

Recommended Input Devices for Power User

• Enhanced keyboard or ergonomic keyboard

• Mouse• Stylus and portable keyboard for PDA or

smart phone• Pen for graphics tablet• 48-bit 1200 × 1200 ppi color scanner• 5- or 6-megapixel digital camera• Headset that includes a microphone• PC video camera Power