Inputs

Inputs

1. Keyboard

   • Contains keys for letters, numbers, symbols, and special keys (ESC, ALT, CTRL, SHIFT).
     • Some contain numeric keypads and space for programmable keys.
     • Ergonomic keyboard - shaped to fit human hands better.
       • Reduces risk of RSI and is more comfortable to use.
     • Concept keyboard - the keys are divided into areas to suit a specific purpose.
       • Benefits children and disabled people as the keys are easier to see and press.
       • Also used in fast food restaurants and cafés. These have a plastic film covering the keys to protect them from spillages.
   • Most PC systems come with a keyboard (and mouse) as standard.

2. Mouse

   • Used for controlling cursor and navigating the OS.
     • Mechanical - contains a ball which is rolled along a flat surface in order for the computer to sense its position.
       • A mouse mat is often needed to improve precision.
         • The mechanic also needs to be cleaned out regularly to improve precision as it collects dust and dirt from the surface.
     • Optical - uses a light sensor to detect motion.
       • A mouse mat is not needed.
         • Doesn't work well on transparent or reflective surfaces.
     • Trackpad - many laptops have a touch sensitive plate that is used to control the cursor.
       • Faces difficulties if the trackpad becomes damp or scratched.
     • A trackpoint is a small button on the surface that the user moves like a joystick.
       • Mostly used on small laptops where there is limited space for a trackpad.
       • Easier for some people to use than a trackpad.
   • Most PC systems come with a mouse (and keyboard) as standard.

3. Touch screens

   • Senses when an area of the screen has been touched. Software then interprets the signal.
     • Resistive - the stylus bridges the gap between two layered screens so the two layers become connected at that point.
     • Capacitive - an insulator is coated with a transparent conductor. A finger touching the screen distorts the screen's electrostatic field.
       • Data types
         • Text
         • Still and moving images
         • Numbers
         • Sound
     • Used in public because they are combined input and output.
   • PDA - personal digital assistant

4. Graphics tablets

   • Sometimes called digitizing tablets.
   • Used to create digital drawings.
     • A stylus is used to draw on a flat plate.
       • It can also be used to easily write in languages like Chinese.
     • The stylus feels like a pencil and feels more natural than drawing with a mouse.
   • Interactive whiteboards are used in classrooms as a combined input and output device.

5. Microphones

   • Speech recognition - a computer matching inputted sound to phonemes.
     • Unreliable as accents and pronunciations of the same word can vary from person to person.

6. Card readers

   • Magnetic strip - has a magnetic stripe containing data.
     • Swiped through a card reader. Easy to read. Can't hold very much data. Easy to scratch and damage. Authorized by signature.
   • Smart card - has a computer chip that contains data.
     • Chip-and-PIN is an example. Can hold far more data than a magnetic strip. The use of PINs makes it more secure than magnetic stripe.

7. Inputs continued

   • Scanners
   • Optical mark recognition
   • Optical character recognition
   • Barcode readers
   • Magnetic ink character recognition
   • Webcams
   • Digital cameras
   • Radio frequency identification (RFID)
     • Uses radio waves to transmit a unique serial number as a form of ID for objects.
     • Software is used to track the position of the item.
       • Since RFID tags that haven't been deactivated can still be tracked, some consider them an invasion of privacy.