Input Devices and Methods

1
Input Devices and Methods

• Objectives
• To understand what input devices are.
• Identify their individual uses
• Be able to identify the difference between manual
  and automated input devices.

2
Input Devices and Methods
Manual input devices are used by people to enter
data by hand.

• Keyboard
• Pointing devices
• Joystick
• Digital camera
• Touch screen

• Scanner
• Concept keyboard
• Graphics tablet
• Microphone

3
Keyboard

• The keyboard is the most common type of input
  device.
• Ordinary computer keyboards have their keys
  arranged in a similar way to those on a
  typewriter.
• This way of arranging the keys is called QWERTY
  because of the order that the keys appear in on
  the first row of letters.

4
Pointing devices
A mouse is a pointing device. It is the next most
common type of input device after the keyboard.

Touch pads and trackballs are also types of
pointing device. They are often used instead of a
mouse on portable computers.
5
Joystick

• The main use of a joystick is to play computer
  games by controlling the way that something moves
  on the screen.
• Joysticks can be used to control movement from
  side-to-side, up-and-down and diagonally.
• A joystick will also always have at least one
  button on it which can be used to make something
  happen like making a character in a game jump or
  fire a gun.

6
Touch screen

• A touch screen can detect exactly where on its
  surface it has been touched.
• Touch screens are used in a lot of fast food
  chains and restaurants because they are easy to
  keep clean and re-program if changes need to be
  made to the menu.

7
Digital camera

• A digital camera can store many more pictures
  than an ordinary camera.
• Pictures taken using a digital camera are stored
  inside its memory and can be transferred to a
  computer by connecting the camera to it.
• A digital camera takes pictures by converting the
  light passing through the lens at the front into
  a digital image.

8
Scanner

• A scanner can be used to input pictures and text
  into a computer.
• There are two main types of scanner
• Hand-held
• Flat-bed.

9
Concept keyboard

• Flat board with a grid of programmable keys on
  its surface.
• A single key or a group of keys can be set up to
  carry out a particular task.
• Paper overlays are placed on top of the keyboard
  with pictures drawn on them to represent what
  will happen if the keys in a certain position are
  pressed.
• Often used with young children in primary schools
  who cant use an ordinary keyboard very well.

10
Graphics tablet

• Has a flat surface and a pen, or stylus, which
  can be used to produce freehand drawings or trace
  around shapes.

• When the special pen touches the surface of the
  graphics tablet data about its position is sent
  to the computer.
• This data is used to produce on the screen an
  exact copy of what is being drawn on the surface
  of the graphics tablet.

11
Microphone
A microphone is used to input sound into a
computer system.

• Often used for voice recognition systems which
  convert sounds made by a user into commands that
  the computer can carry out.
• Useful for people who cant use ordinary input
  devices such as the mouse and keyboard.
• As computers become more powerful in the future,
  voice recognition will be a much more common
  input method for all computer users.

12
Input Devices and Methods
Automated input devices can input data
automatically without any need for human
intervention
Optical Mark Recognition (OMR)
Optical Character Recognition (OCR)
Magnetic Ink Character Recognition (MICR)
Bar Code Readers
Magnetic Stripe
Light Pen
Sensors

13
Bar Code Reader

• Used to read the code on a bar code
• It uses a laser beam that is sensitive to the
  different reflections from the lines and the
  spaces.
• The reader translates the reflected light into
  digital data that is transferred to a computer
  for immediate action or storage.
• Commonly used in supermarkets and libraries

14
Optical Mark Recognition (OMR)

• Similar to a bar code reader but uses infra-red
  light to scan marks on prepared forms
• multiple-choice examination answer sheets
• lottery tickets.

15
Magnetic Ink Character Recognition (MICR)

• Uses special ink which contains iron particles
  that can be magnetised and then read when the
  printed numbers passes through a MICR reading
  machine.
• It is expensive,
• MICR is mainly used by banks.
• The account number, the cheque number and the
  branch number are pre-printed on a cheque.

16
Sensors

• Detect changes in the physical or chemical
  environment and convert them into electrical
  signals.
• These signals can then be digitised and used by
  a computer
• There are a huge range of sensors used to
  measure
• heat
• light
• Sound
• Movement etc, etc, etc

17
Magnetic strip reader

• Used to read data from a magnetic strip
• Thin strips of magnetic tape - usually found on
  the back of plastic credit and debit cards.
• When the card is inserted into a reader (in an
  Automatic Teller Machine or ATM for example) the
  tapes slides past a playback head similar to that
  used in a tape recorder.
• This reads the data from the stripe and passes it
  to a computer.

18
Smart Card (Chip Pin)

• Data stored on an embedded micro processor.
• Can store much more than a magnetic strip card.
• More secure because it doesnt just rely on a
  signature.

19
Input Devices and Methods

• Objectives
• To understand what input devices are.
• Identify their individual uses
• Be able to identify the difference between manual
  and automated input devices.