Hardware Devices

Hardware Devices

1. Inputs

   • Mouse: Used to detect movement on a 2D plane, so that a user can navigate a cursor across a screen. A mouse usually uses either a ball or laser and light sensor to detect this motion.
   • Keyboard: Uses a grid of circuits which correspond to keys placed above them. When a key is compressed, it completes one circuit on the grid. An on board chip figures out which key has been compressed
   • BarCode Reader: A linear beam of light shines on a series of dark lines and white spaces. The width of these lines represent different values, and the device can detect the width of these lines using the light bounced off the surface
   • Scanner: An optical device that can digitalise an image from the real world
     • Flatbed: A document is placed on a glass plate, and a CCD array + strong light source move under it. Mirrors are used to focus the image of the document onto the array
     • Finger Print Scanner: Can create an image of the unique, rough surface on the tip of a persons finger
     • Retina Scanner: Uses a strong light to take an image of the blood-vessel structure inside a persons retina
     • Iris Scanner: Takes a high-res picture of a persons iris, which can be analysed for unique patterns
     • Optical mark Scanner: A user checks boxes on a pre-printed form. A high speed scanning system can detect whether or not boces have beeen checked. Usually used to digitalise surveys and exam papers.
     • Optical character reader: An advanced version of a Optical mark scanner, can use algorithms to analyse a written word, and figure out what it is.

2. Outputs

3. Secondary Storage