Input - Information Technology - Info 1 AS

Keyboard

• Most common input device in most computer systems is QWERTY keyboard.
• Keys for all letters plus special keys such as ESC, ALT, CTRL, SHIFT and function keys
• Variations on this layout in different countries (extra keys such as a numeric keypad.
• Ergonomic keyboards designed to try to reduce repetitive strain injury (RSI) - people may find it weird to use as used to normal keyboard

• Devices like mobile phones (smaller versions of keyboards) usually called keypads
• Often use multiple key presses to select letters - full size keyboard not practical when using devices this size.

Mouse

• Most common pointing device used to move pointer around the screen and select options by clicking. (can be connected to the computer via a cable or wireless)

• Two main types of mouse ( OPTICAL & MECHANICAL )
• Mechanical - rolling ball and computer senses its position on flat surface. Works best on mouse mat
• Optical - Uses a light sensor to detect motion (does not need a mouse mat)

• Both types of mouse usually have two or three buttons which can be clicked - many have a scroll wheel to make dragging and scrolling easier
• Trackball - same job as a mouse. Has a ball on the surface rather than underneath. Ball rolled using fingers/palm of hand. Sometimes used with laptop's as they are easier to use in confined spaces
• Many laptops have trackpads - user moves finger across sensitive plate to control cursor.
• Trackpoint - small button works like a joystick. Seen on (mobile phones, PDA's and laptops)

Concept Keyboards

• Divided into areas - label to suit actually use
• Special software interprets key press for the computer
• Can be used in checkout tills or restaurants so user can press name of item sold rather than remembering price of it.

• May have plastic film to protect it from food and drink spills
• Used for children/people with disabilities - small child hears a question asking what colour an object is. They then respond by pressing the correct section of a keyboard that has been divided into six sections (representing a colour)

Touch Screen

• Senses area of the screen which has been touched (by wires embedded in screen/patterns of infra-red light beams) - software interprets signal
• Touch screens - often used in public areas (easy to use, combine input and output & doesn't need any extra devices such as a mouse)
• Allow limited selection of times from the menu

• Virtual keyboard for short items of text
• PDA's - use touch screens as combined input/output devices (small stylus or a fingerprint to select items/draw/write)

• Have handwriting recognition software so handwritten notes can be converted into characters (drawn with dictionary of letters and numbers)
• May be trained to recognise handwriting of person using it.

Graphics Tablets

• Sometime called 'Digitising Tablets' - mainly used for drawing
• Stylus used to draw on a flat plate
• Stylus feels like a pencil & more natural than a mouse.
• Can also be used to select icons or for writing in languages (Chinese)…