Cs100 lec 3 cont2 hardware input & output )

Hardware Components

• Input Devices

• Output Devices

Input Devices - Consist devices that translate data into a form the computer can process

Keyboard • is a device that converts letters, numbers, and other

characters into electrical signals that can be read by the computer’s processor.

2 types

1. Traditional computer keyboard (104 - 105 keys)

2. Specialty keyboards and terminals (touch tone telephone keypads to keyboards featuring pictures of food for use in fast-food restaurants

TRADITIONAL KEYBOARD SPECIALTY KEYBOARD

Pointing devicesControl the position of the cursor or pointer on the screen1. mouse and its variants:

• trackball – a movable ball, mounted on top of a stationary device, that can be rotated using your fingers or palm

• pointing stick – looks like a pencil eraser protruding from the keyboard between G, H, and B keys

• touch pad – a small, flat surface over which you slide your finger

2. touch screen – a video display screen that has been sensitized to received input from the touch of a finger

3. Pen Input: • Pen-based computer system

– allows users to enter handwriting and mark onto a computer screen by means of a penlike stylus rather than typing on a keyboard (ex. handheld and digital notebook)

• Light pen – a light-sensitive penlike device connected by a wire to the computer terminal

• Digitizer – uses a mouselike copying device called a puck, or an electronic pen, which can convert drawings and photos to digital data. (ex. digitizing tablet)

Source Data-Entry DevicesData are entered directly from the source. It creates machine-readable data on magnetic media or paper or feed it directly into the computer’s processor

• 1. Scanning devices. Scanners use light-sensing equipment to translate images of text, drawings, photos, and the like into digital forms.

• a. Imaging System

b. Bar-code reader

c. Mark-recognition and Character-recognition devices.

c.1 Magnetic-ink character recognition (MICR)

c.2 Optical-mark recognition (OMR)

c.3 Optical-character recognition (OCR)

d. Fax machines

d.1 Dedicated fax machinesd.2 Fax modem

Source Data-Entry Devices2. Webcam – a camera that attaches to a computer to record moving images that can then be posted on a website in real time

3. Digital cameras – electronic camera that uses a light-sensitive processor chip to capture photographic images in digital form on a small diskette inserted in the camera or on flash-memory chip.

4. Human biology-input devices. Characteristics and movements of the human body, when interpreted by sensors, optical scanners, voice recognition, and other technologies, can be form of input.

a. Biometric system. b. Line of sight systems

VOICE RECOGNITION

FINGER SCANNER

HAND SCANNER

EYE SCANNER

Output DevicesConsists of devices that convert machine-readable information, obtained as a result of processing, into people-readable form

2 types• 1. Softcopy – data that is shown on a display screen or is in audio

or voice form

• 2. Hardcopy – printed output

• Other Outputs

Softcopy• a. Display screen – also called as monitors

2 Types

• a.1 Cathode-Ray Tube (CRT)- is a vacuum tube used as a display screen in a computer or video display terminal

•a.2 Flat-panel displays are made up of two plates of glass separated by a layer of a substance in which light is manipulated (ex. Liquid crystal display (LCD)

Hardcopya. Impact Printer- forms characters or images by striking a mechanism such as a print

hammer or wheel against an inked ribbon. (ex. Dot matrix)

b. Nonimpact Printers form characters and images without direct physical contact between the printing mechanism and paper.

3 Typesb.1 Laser Printer

b.2 Ink-jet Printer

b.3 Bubble-jet Printer

b.4 Thermal Printer

c. Plotters. 3 Typesc.1 Pen

c.2 Electrostatic

c.3 Large-format

d. Multifunction

Other Output: Sound, Voice, and Video • 1. Sound Output devices – produce digitized sounds, ranging from beeps

and chirps to music. (ex. speaker)

•2. Voice Output Devices – convert digital data into speech-like sounds. (ex. in telephone answering machine, cars, toys and games)

•3. Video Output – video consists of photographic images, which are played at 15-29 frames per second to give the appearance of full motion.