1. Chapter 2: Input and output devices
Revision

2. Alphanumeric keyboard – used for and numbers
2.1 Input devices and their uses
Keyboards
Alphanumeric keyboard – used for entering text and numbers
Alphanumeric keyboard – used for and numbers
Numeric keypad – small keyboard that just has number used at ATM’s
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

3. Mouse – used with most GUI devices
2.1 Input devices and their uses
Pointing 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

4. Touch screen user selects item on screen by touching it on the surface
2.1 Input devices and their uses
Pointing 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

5. Scanner – device that ‘scans’ images, book pages etc.
2.1 Input devices and their uses
Input – 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

6. A normal PC has no senses but we can give it some.
2.1 Input devices and their uses
Sensors
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

7. 2.1 Input devices and their uses
Sensors
Examples

8. 2.1 Input devices and their uses
Typical Exam Question
Why does a computer not understand physical variables (real world) read from sensors?

9. 2.1 Input devices and their uses
Answer
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

10. Smart Card/’chip’ Reader – used in modern credit cards
2.2 Direct Data entry and associated devices
Input – 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

11. 2.2 Direct Data entry and associated devices
Magnetic 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)

12. 2.2 Direct Data entry and associated devices
Optical 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)

13. 2.2 Direct Data entry and associated devices
Optical Character Reader
OCR
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
Faster method of data entry and more accurate than a keyboard (manual input)

14. 2.2 Direct Data entry and associated devices
Optical Character Reader
OCR
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
Faster method of data entry and more accurate than a keyboard (manual input)

15. 2.2 Direct Data entry and associated devices
Barcode Reader
Barcode Reader
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
Faster method of data entry and more accurate than a keyboard (manual input)

16. 2.2 Direct Data entry and associated devices
Radio Frequency Identification
RFID
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
Faster method of data entry and more accurate than a keyboard (manual input)

17. 2.2 Direct Data entry and associated devices
Radio Frequency Identification
RFID
The RFID tag can be affixed to an object and used to track and manage inventory, assets, people etc
Seaports – To track daily arriving containers.
People Tracking – The United Nations uses RFID technology to track the movements of its personnel.
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.
Retail - In the retail section, taking inventory of stock on the shelf is dramatically faster.
Paying for goods using debit/credit cards

18. 2.2 Direct Data entry and associated devices
Typical Exam Question
Compare and contrast a OCR, OMR, MICR and a keyboard as a method of data entry?

19. Device Use Benefit Drawback OMR OCR MICR Keyboard
2.2 Direct Data entry and associated devices
Device
Use
Benefit
Drawback
OMR
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

20. Digital/multimedia projector used when very large viewing is required.
2.3 Output devices and their uses
Output 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
Load speaker converts electrical signals into sound waves and essential for movies, video conferencing and sound waves.
Digital/multimedia projector used when very large viewing is required.

21. Not affected by hot/cold or dusty environments
2.3 Output devices and their uses
Dot-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

22. Inkjet Printer offers cheap high quality printing
2.3 Output devices and their uses
Inkjet 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.

23. 2.3 Output devices and their uses
Laser 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 – pages on a single toner
Laser printers commonly used in offices since they print very quickly , quite cheap to use and can work quietly

24. Expensive to buy 3D printers and associated printing materials
2.3 Output devices and their uses
3D 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

25. 2.3 Output devices and their uses
Actuator
An actuator is a device that can be used to affect or control the real world

26. 2.3 Output devices and their uses
Actuators
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
Heater/coolers: heat or cool things down – computer switches heating in greenhouse