Input Devices

• A charge-coupled device (CCD) is a light-sensitive integrated circuit that captures images by converting photons to electrons. Used in 2D scanners to convert an image to its electronic form.
• Scanners can be:

  • 2D
  • 3D
• Analogue


  Continuous varying data
• Actuator


  An electromechanical device that controls electrical devices
• ADC

  Analogue to Digital converter - A device that converts analogue signals from devices to digital signals understandable to a computer
• ASCII

  American Standard Set Information Interchange - A 7 bit character code for representing the characters on a keyboard
• Barcode


  A series of dark and light parallel lines of varying thickness used to identify products
• CAD

  Computer Aided Design - Design software used in creating 3D objects
• Capacitor


  An electronic component that stores electric energy in the form of electric charges and creates a potential difference
• Charged coupled device


  CCD - A light-sensitive circuit that converts an image to its digital value
• DAC

  Digital to Analogue Converter - A device that converts the digital data from the computer into analogue values that can control devices
• In a barcode the numbers 0 to 9 are each represented by a unique series of lines.
• Guard bar = longer bars placed at each side of barcpdes
• Universal Product Code (UPC) defines a standard to represent each digit using bars in a barcode
• Point Of Sale (POS) is computer technology to record all pertinent data about an item, normally by scanning the item's UPC (Universal Product Code). When a scanner reads the code, it can display the item's price, record the item as sold, and help track the remaining inventory.
• QR codes can store up to 7000 digits whereas normal barcodes can

  only store 30 digits.
• ADVANTAGES OF DIGITAL CAMERAS:

  • Don't require film or the photos being developed and printed.
  • Can be connected to a computer using USB, Wi-Fi or Bluetooth connectivity
  • Photos and videos can be transferred in seconds.
  • Unwanted photos or videos can be deleted.
• Microprocessors within digital cameras can automatically...

  • adjust the shutter speed
  • focus the image
  • operate the flash
  • adjust the aperture size
  • adjust the size of the image
  • remove ‘red eye’ when the flash has been used
  • etc...
• The memory occupied by the photo can be reduced by

  reducing its resolution.