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Chapter 2: Input and output devices Revision

Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

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Page 1: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

Chapter 2: Input and output devicesRevision

Page 2: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesKeyboards

Alphanumeric keyboard – used for and numbers

Numeric keypad – small keyboard that just has number used at ATM’s

PIN Pad – used for entering PIN when paying for items using credit card

Also found on electronic security doors to unlock them

Alphanumeric keyboard – used for entering text and numbers

Numeric keypad – small keyboard that just has number used at ATM’s

Page 3: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesPointing Devices

Mouse – used with most GUI devices

• Touch Pad – mainly found on most laptops because take less space than a mouse

• Trackball/Tracker ball – not moved like a mouse but has a large ball that spins to control curser

– Suitable for very young or elderly with limited movement

Page 4: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesPointing Devices

Touch screen user selects item on screen by touching it on the surface

• Graphics Tablet – pointing device often used by artists and designers to input graphics – allows hand drawn sketches

• Joy stick – mainly used for playing games but small ones can also be found on mobile phones

• Light Pen – used a pointing device to ‘write’ on the screen of a computer

Page 5: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesInput – audio/visual devices

Scanner – device that ‘scans’ images, book pages etc.

Digital Camera – device that captures photos and can be stored on a memory card

• Video Camera – device that captures moving images or video

• Web Cam – basic video camera used for live feeds but has poorer quality

• Microphone – converts sound into a signal that can be fed into a computer

Page 6: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesSensors

• A computer or microprocessor has no way of knowing what is happening in the real world

• As humans or animals we use our eyes, ears , mouths, skin and noses to sense thing around us – our senses

• A normal PC has no senses but we can give it some.

A sensor is a device that converts a real world property into data that a computer can process

Page 7: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesSensors

Examples

Page 8: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesTypical Exam Question

Why does a computer not understand physical variables (real

world) read from sensors?

Page 9: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.1 Input devices and their usesAnswer

Real world measurements are collected as an analogue signal from the sensor

A computer only understands digital signals

An ADC (Analogue-to-digital converter) is needed to convert the signal so a computer understands the signal

Page 10: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesInput – Card Readers

Magnetic Strip Reader – data can be stored in the form of magnetised dots• Data can be entered faster and more accurately • Data stored on the card include:

– Credit card number– Expiry date– Customer name

Smart Card/’chip’ Reader – used in modern credit cards• Smart and satellite TV decoder cards can store much more data

that magnet strip cards– Credit card number– Expiry date– Customer number • Even an image of customer

Page 11: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesMagnetic Ink Character Reader MICR• Allows details from bank cheques to be

read from bank cheques quickly and accurately because it’s a automatic method

• Cheque number and bank account number are print at the bottom of each cheque is a special magnetic ink using a special font

• These numbers can be detected using the MICR Reader

Faster method of data entry and more accurate than a keyboard (manual input)

Page 12: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesOptical Mark Reader OMR• Allows data from ‘multiple choice’ type

forms to be read quickly and accurately into a computer

• Special OMR Forms are used which have spaces that can be coloured using a pencil

• These marks are then detected by the OMR Scanner

• Used in multiple choice exam answers and lottery tickets

Faster method of data entry and more accurate than a keyboard (manual input)

Page 13: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesOptical Character Reader OCR

Faster method of data entry and more accurate than a keyboard (manual input)

• Converts images or text from hard copies into computer files which can be edited in word processors

• Typically used to scan pages from a book

• OCR software analysis letter shapes and generates matching electronic files

• Some advanced OCR software also recognises handwriting

Page 14: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesOptical Character Reader OCR

Faster method of data entry and more accurate than a keyboard (manual input)

Self-registration Immigration System:• A device that can automatically enter information on

foreign visitor’s entry:

• Facilitate foreign visitors with filling out entry- exit registration information

• Reduce manual entry workload of immigration registration cards

• Improve data accuracy of immigration information collection

Page 15: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesBarcode Reader Barcode

Reader

Faster method of data entry and more accurate than a keyboard (manual input)

• A Barcode is simply a numeric code represented as a series of lines

• These lines can be read by a barcode reader or scanner

• Barcode readers are typically used at point-of-sale (POS) in shops

• Far quicker and more accurate than typing in code using a keypad

Page 16: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesRadio Frequency Identification RFID

Faster method of data entry and more accurate than a keyboard (manual input)

• An RFID tag is a very small and thin silicon chip that can be placed on a sticker

• RFID tags are used in some passports and by companies who track the movement of products

• An RFID reader can read objects from a distance and can be written to and read from

• Can be used to store and read information including biometric readings and photos

• Far quicker and more accurate than typing in code using a keyboard

Page 17: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesRadio Frequency Identification RFID

Airlines – Airlines uses RFID tags to track passenger bags to reduce the number of lost bags and make it easier to route bags if customers change their flight plans.

Seaports – To track daily arriving containers.

People Tracking – The United Nations uses RFID technology to track the movements of its personnel.

The RFID tag can be affixed to an object and used to track and manage inventory, assets, people etc

Retail - In the retail section, taking inventory of stock on the shelf is dramatically faster.Paying for goods using debit/credit cards

Page 18: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devicesTypical Exam Question

Compare and contrast a OCR, OMR, MICR and a keyboard as a method of data entry?

Page 19: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.2 Direct Data entry and associated devices

Device Use Benefit DrawbackOMR Used to mark

multiple choice exam papers

Automatically corrects exam papers more quickly and accurately than a teacher marking

Boxes must be filled out properly using a pencil otherwise wont read

OCR Used to scan hardcopies of books into a computer for later editing

Very fast and fairly accurate of transferring hardcopies into computers files rather than typing using a keyboard.

Can be slower in comparison to OMR and MICR

MICR Used to read special characters on cheques

Fast and accurate method of data entry – less errors than typing on number pad

Keyboard Used to manually input alphanumeric data

Useful for typing alphanumeric and can easily edit.

Slowest method compared with others and more likely to make mistakes

Page 20: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesOutput Devices: Audio Visual

CRT Monitor stand for cathode-ray tube and have been around for a long time – cheaper and sometimes used by designers because can offer true colour

Flat Screen (CRT or LCD) Monitor – replaced CRT monitors, are light and take up little desk space

Digital/multimedia projector used when very large viewing is required.

Load speaker converts electrical signals into sound waves and essential for movies, video conferencing and sound waves.

Page 21: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesDot-Matrix Printer

• A dot-matrix printer is named after the pattern (a grid or ‘matrix’) of dots used when creating the paper printout.

• A tiny pin impacts against an ink ribbon which leaves a pattern of tiny dots. Since the PIN hits the paper several carbon copies can be made in one go.

• Dot-matrix printer is a continuous stationary – uses long continuous strips of paper.

• So, where cheap, low-quality printouts are required, dot-matrix printers are used. An example is shop receipts.Not affected by hot/cold or dusty environments

Page 22: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesInkjet Printer

• Inkjet Printer offers cheap high quality printing

• Squirts tiny droplets of ink onto paper – linking drops can produce full colour photos

• Small dots allow for high quality images

• Very quiet to use as they don’t have many moving parts

• Cheap to buy however the ink for the printer can be expensive.

Page 23: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesLaser Printer

• Very complex printers and expensive to buy

• The laser and toner system allows for very fast printing compared to other printers (just a few seconds per page).

• Cheap because they use a toner – uses fine dust on the paper– Can produce 5000 – 10000 pages on a

single tonerLaser printers commonly used in offices since they print very quickly , quite cheap to use and can work quietly

Page 24: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their uses3D printer

• 3D printer is a new generation of printer that can produce 3D objects (in different materials)

• 3D Printer works by adding tiny layers on top of each other to produce the object

• Can be used to produce objects from 3D models on the computer - prototype models

• Expensive to buy 3D printers and associated printing materials

Page 25: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesActuator

An actuator is a device that can be used to affect or control the real world

Page 26: Chapter 2: Input and output devices Revision. 2.1 Input devices and their uses Keyboards Alphanumeric keyboard – used for and numbers Numeric keypad –

2.3 Output devices and their usesActuators

Motor: Provides movement – washing machine door etc.

Pump: motor attached to a device that can pump water

Buzzer: Provides noise – microwave buzzer – sirens or electric bells (in schools)

Light Bulbs and LED’s: Motor attached to a device that can pump water – car dashboard is car has problems