IT 111 - Module 6

Introduction to Computing: Module 6

Input Hardware

These are devices that translate data into a form the computer can process.

It translates words, numbers, sounds and pictures into binary 0s and 1s (off or on electrical signals or light pulses)

Output Hardware

These are devices that translate information processed by the computer into a form humans can understand.

It translates binary code into words, numbers, sounds, and pictures.

Keyboards, Pointing Device, and Source Data-Entry Devices

What are the three major types of input hardware?

Keyboards

It converts letters, numbers and characters into electrical signals.

▹ You press a key

▹ This interrupts the current flow through the circuits

▹ Processor determines where the breaks occurs

▹ It compares the location of the breaks with the (x, y) character map for the language on the keyboard’s ROM chip

▹ A character is stored in keyboard memory

▹ The character is then sent to PC as a data stream via wire or wireless connection.

▹ OS interpret its own operating-system-specific commands and send the others to the application for interpretation.

▹ Most keyboards are QWERTY – named for the first six letters on the top left of the keyboard.

▹ Keyboards are either tactile (physical) or touch screen (virtual)

How do keyboards work?

▹ 104-108 keys desktop standard

▹ 80-85 keys for laptops

▹ Wired (Connect to CPU via a serial or USB port)

▹ Wireless [IR (infrared) technology, Radio Frequency (RF) technology, Bluetooth]

What are the types of keyboards?

Dumb Terminals, Intelligent Terminals

What are the two terminal types?

Dumb Terminals

Also know as Video Display Terminal (VDT) and can do input and output only, no data processing.

Intelligent Terminals

It is a type of terminal that has screen, processor, keyboard, and memory and can perform some independent functions.

Automated teller machine; point-of-sale terminal, mobile data terminal

Pointing Devices

These control the position of the cursor or pointer on the screen and allow the user to select options displayed on the screen.

Mouse

It is the principal pointing device.

Mechanical Mouse

A mouse wherein a ball inside the mouse touches the desktop surface and rolls with the mouse.

Optical Mouse

A mouse that uses laser beams and special chips to encode data for the computer.

Trackball

A movable ball mounted on top of a stationary device. Good for locations where a mouse can’t move around enough.

Touchpad

It is a pointing device. To use: slide your finger over this small flat surface. Click by tapping your finger on the surface. It may require more practice to use than a mouse.

Pointing stick

Located between the keys on a laptop keyboard, it is a pressure-sensitive device that allows the user to control the pointer by directing the stick with one finger.

Touch screens

A video display screen sensitive to receive input from a finger touch. Used in ATMs, information, kiosks, reservation kiosks, voting machines, cellphones, tables, and e-books.

Multi-touch Screens

Display screen that allow two or more fingers or other gestures such as pinching motions to be recognize as input at any one time. It allow pinching and stretching gestures on the screen to control zooming.

Pen input

Uses a pen-like stylus for input.

Uses handwriting recognition to translate cursive writing into data (hand writing recognition).

Light Pen

A light-sensitive pen-like device that uses a wired connection to a computer terminal.

Bring the pen to the desired point on the display screen and press a button to identify the screen location.

Used by graphics artists, engineers, and in situations that require covered hands.

Digitizer

Uses an electronic pen or puck to convert drawings and photos to digital data.

Digitizing tablets are often used in architecture.

Digital Pen

Writing instrument

Writers can write on paper

A tiny camera in the pen tip captures the writing

A microchip in the pen converts the pen to digital ink

The writing is sent as an image file to the computer

Some versions require special paper

Scanning & Reading Devices

Source data-entry devices that create machine-readable data and feed it directly into the computer (no keyboard is used).

Scanners

User light-sensing equipment to translate images of text, drawings, and photos into digital form.

Image Scanners

These are used in electronic imaging.

Resolution

It refers to the image sharpness, measured in dots per inch (dpi)

Flatbed scanners

It works like photocopiers - The image is placed on the glass surface, then scanned.

Sheet-fed, handhelp, and drum

Other types of scanners.

Bar-Code Readers (source data entry)

Photoelectric (optical) scanners that translate bar code symbols into digital code. The digital code is then sent to a computer. The computer looks up the item and displays its name and associated information.

1D

2D

3D

What are the three bar code types?

1D (regular vertical stripes)

A type of bar code that holds up to 16 ASCII characters.

2D (different-sized rectangles)

A type of bar code that can hold 1000 to 2000 ASCII characters.

3D

A type of bar code.

It is a “bumpy” code that differentiates by symbol height.

Can be used on metal, hard rubber, other tough surfaces.

Radio-Frequency Identification (RFID)

Based on an identifying tag bearing a microchip that contains specific code numbers. These code numbers are read by the radio waves of a scanner linked to a database.

Active RFID

A type of RFID wherein tags have their own power source and can transmit signal over a distance to a reader device.

Passive RFID

A type of RFID wherein tags have no battery power of their own and must be read by some sort of scanner.

MICR – magnetic-ink character recognition

A mark recognition reader that uses special magnetic inks.

It must be read by a special scanner that read this ink.

Used on back checks.

OMR – optical mark recognition

A mark recognition reader that uses a special scanner that reads bubble (pencil) marks.

Used in standardized tests such as the SAT and GRE.

OCR – optical character recognition

A mark recognition redear that convers scanned text from images (pictures of the text) to an editable text format.

Digital Cameras

An image-capture device that uses a light-sensitive processor chip to capture photographic images in digital form and store them on a small disk in the camera or on flash memory cards.

Most can be connected to a PC by USB; smartphones include digital cameras.

Webcam

Video cameras attached to a computer to record love moving images then post them to a website in real time.

Can be attached externally or built into the computer/device.

Frame-grabber video card

A video card that can capture and digitize 1 frame at a time.

Full-motion video card

A video card that can convert analog digital signals at rates up to 30 frames per second

Looks like a motion picture.

Audio-Input Devices

It records analog sound and translate it into digital files for storage and processing.

Sound Board

MIDI Board

What are the two ways to digitize audio (often via microphone)?

Sound Board

An add-on board in a computer that converts analog sound to digital sound, stores it, and plays it back to speakers or amp.

MIDI Board

Stands for Musical Instrument Digital Exchange

Uses a standard for the interchange between musical instruments, synthesizers, and computers.

Speech Recognition Systems

It uses a microphone or telephone as an input device. Converts a person’s speech into digital signals by comparing against 200,000 or so stored patterns.

Used in places where people need their hand free – warehouses, car radios, store exchange trades.

Helpful for people with visuals or physical disabilities that prevent them from using other input devices

Sensors

Input device that collects specific data directly from the environment and transmits it to a computer.

Can be used to detect speed, movement, weight, pressure, temperature, humidity, wind, current, fog, gas, smoke, light, shapes, images, earthquake, etc.

Biometric-Input Devices

Biometrics is the science of measuring individual body characteristics, then using them to identify a person through a fingerprint, hand, eye, voice, or facial characteristics.

*Data will be input from more and more locations

*Use of source data entry will increase.

▹ Better input devices for people with disabilities

▹ Better speech recognition

▹ Better touch and gesture-recognition input

▹ Pattern recognition and improved biometrics

▹ Brainwave input device

What is the future of input.

Softcopy

Data shown on a display screen or is in audio or voice form; it exists only electronically. This kind of output is not tangible; it cannot be touched. You can touch disks on which programs are stored, but the software itself is tangible.

Hardcopy

Tangible output, usually printed. The principal examples are printouts, whether texts or graphics from printers. film, including microfilm and microfiche, is also considered hard copy.

active display screen

It is the size of a computer screen measured diagonally from corner to corner in inches.

15-30 inches (laptops 12-18 inches 8.4-14.1 inches, and smartphones 2.5-4.1 inches)

Desktop computers are commonly what size?

Aspect Ratio

It is the proportional relationship of a display screen’s width and height.

4:3 aspect ratio

What is the aspect ratio of standard displays?

16:9 or 16:10

What is the aspect ratio of wide screen displays?

Dot pitch (dp)

It is the amount of space between adjacent pixels (square picture elements) on screen.

The closer the pixels, the crisper the image.

Get .25 dp or better.

Resolution

It refers to the image sharpness

The more pixels, the better the resolution

Expressed in dots per inch (dpi).

Color depth (bit depth)

It is the number of bits stored in a dot (pixel).

The higher the number the more true colors.

24-bit color depth is better than 8-bit depth, but it needs more video card memory.

Refresh rate

It is the number of times per second the pixels are recharged – a high rate gives less flicker.

▸ Microcomputers come with graphics cards (video cards) that work with the screen.

▸ Graphics cards have their own memory (VRAM) which stores each pixel’s information.

▸ The more VRAM, the higher resolution you can use.

▸ Desktop publishers, graphics artists, and gamers need lots of VRAM.

More informations about graphic cards.

flat-panel displays

The most common type of display that are made of two plates of glass separated by a layer of a substance in which light is manipulated.

liquid crystal display (LCD)

One type of flat-panel display in which molecules of liquid crystal line up in a way that alters their optical properties, crating images on the screen by transmitting or blocking light.

Plasma displays

A type of display wherein a layer of gas is sandwiched between two glass plates, and when voltage is applied, the gas releases light, which activates the pixels on the screen and forms an image.

Cathode ray tube (CRT) and others

Other types of displays that are falling out of use.

Multiple screens

Splitting the monitor display area into this, to view different documents at once.

dpi (dots per inch)

How is printer resolution measured?

1200 x 1200 is the most common for microcomputers.

impact printers (dot matrix printers)

A printer that prints by striking the paper directly

non-impact printers

A printer that does not have direct contact with the hardcopy medium. (such as laser printers and inkjet printers)

Laser Printers

▹ Like a dot-matrix printers, it creates images with dots.

▹ Run with software called a page description language (PDL)

▹ Comes with one or both types of PDL: PostScript or PCL (Printer Control Language). In desktop publishing,

PostScript is the preferred PDL.

▹ Have their own CPU, Rom and memory (RAM)

Inkjet Printers

▹ Spray onto paper, electrically charged dropletsof ink from four or more nozzles through holes in a matrix at high speed.

▹ Form images with little dots.

Thermal printers

A non-impact printer that has low to medium resolution printers that use a type of coated paper.

Thermal wax-transfer printers

A non-impact printer.

Print a wax-based onto paper.

Photo-printers

A non-impact printer.

Specialized machine for printing continuous-tone photo prints with special paper and color dyes.

Multi-function printers

▹ Printers that combine several capabilities such as printing, scanning, copying, and faxing.

▹ Cost less and take up less space than buying the four separate office machines.

▹ But if one component malfunctions, so will the other functions.

Plotters

▹Designed for large-format printing

▹ Specialized output device to produce large high-quality, 3D graphics in a variety of colors.

▹ Used by architects, engineers, and map-makers

Pen plotters

A plotter that use one or more colored pens.

Electrostatic plotters

A plotter that lie partially flat on a table and use other as photocopiers do.

Large-format plotters

A plotter that are large scale inkjet printers used by graphic artists.

Sound output

▹ produces digitized sound, even 3D sounds

▹ You need a sound card and sound software

▹ Good speakers can improve the sound

Voice Output

▹ converts digital data into speech like sounds

▹ Used in phone trees, cars, toys and games, GPS systems, and TTS (text-to-speech) systems for hearing-impaired people.

Video Output

– photographic images played quickly enough to appear as full-motion

▹ Requires powerful processor and video card.

▹ Video files are large, so a lot of storage is needed, too.

▹ Videoconferencing is a form of video output.

▸ More unusual forms of output

▸ More data used in (Big Data)

▸ More realistic output

▹ Better and cheaper display screens

▹ Printers that use less ink

▹ Movie-quality video for PCs

▹ Increased use of 3D output

The Future of Output

Health Matters

▹ Overuse injuries and repetitive stress injuries

▹ Result when muscle groups are forced through fast, repetitive motions.

▹ May effect data-entry operators who average 15,000 keystrokes an hour.

▹ May effect computers users whose monitors, keyboard, and workstation are not arranged for comfort.

▹ Carpal tunnel syndrome: Cause by pressure on the median nerve in the wrist, through short repetitive movements.

▹ Eyestrain, headache, back and neck pains can be problems.

▹ Electromagnetic fields may be harmful.

Carpal Tunnel Syndrome

It is caused by pressure on the median nerve in the wrist, through short repetitive movements.

Ergonomics

It is the methodology of designing a workplace to make working conditions and equipment safer and more efficient.

▹ Keyboards must be placed at the correct height depending on each worker’s size; detachable keyboards are useful.

▹ Monitor refresh rates must be fast enough to avoid eyestrain.

▹ Monitor heights must be correct for comfortable viewing; use a tilting screen.

▹ Wrist rests may help avoid carpal tunnel syndrome.