1.4 - Input Devices Flashcards
Describe touch screens
- senses when an area of screen has been touched by wires or infra red light beams
- used in public areas as they’re easy to use and combine input and output
Describe a graphics tablet
- mainly used for drawing
- stylus is used to draw on a flat plate
Describe speech recognition
- involves user speaking into a microphone
- sounds of words are compared with collection of sounds and are converted into computer readable text using special software
Why is speech recognition not very reliable?
- different accents and voices can be interpreted wrong
- background noise can interfere
- words that sound the same but are spelt differently can not be distinguished so the context has to be looked at
Describe magnetic strip cards
-they are swiped through a card reader and are easy to read but can easily be scratched and they don’t hold much data
Describe a smart card e.g chip and pin
- has a computer chip which can have data written on to it and it can hold a lot
- authorised by a pin number so it is more secure
- chip allows data to be encrypted
Describe RFID (radio frequency identification)
- uses radio waves to transmit a unique serial number as a form of ID for objects
- tag can be attached which can be used to track the position of the item
- sometimes called smart labels
- used in transport to trace goods that may be of good value
Describe a scanner
- used to turn paper based pictures into digital images
- a beam of light passes across the page and senses the colour of various aread
Describe an Optical Mark Recognition
- used for lottery tickets and multiple choice exams
- uses a light beam to sense the position of marks on the paper
What are the advantages and disadvantages of an OMR?
- expensive to set up
- inflexible as only allows users to select from a list of choices
- results are quick and accurate when there is a large volume of data
Describe Optical Character Recognition (OCR)
- a paper document is scanned and each part of the image is compared to a dictionary of known shapes to convert it to text
- used for input forms which have been filled out by client
Describe barcode readers
- used in EPOS systems (paying in store)
- they have built in error checking
- a barcode can be scanned which enters the product number into the computer system
Describe MICR (magnetic ink character recognition)
- used by banks to process cheques
- cheque number is printed using magnetic ink
- magnetic reader then translates these into numbers that can be stored in the computer systen
Describe sound input
Sound has to be encoded as a digital signal to be entered into the computer
Describe video input
-video cameras can record the still pictures and the data can be loaded onto a computer to be edited
