input devices
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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