F451- Input Devices

Optical Character Recognition:

• Shapes of individual characters are scanned and recorded optically 
• Shapes are compared to a library of possible characters

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Uses:

• Software can turn input into audible output for the blind

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Disadvantage:

• Unreliable form of input-­only effective when having to recognise a standard (printed) character set rather than hand-­writing

Optical Mark Recognition:

• Marks are positioned in specified locations
• Reader identifies location of mark
• Location of the mark equates to a value

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Uses:

• To mark multiple choice exams

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Advantage:

• Marking is a lot faster and more accurate

Magnetic Ink Character Recognition:

• Special characters are printed on a document in magnetisable ink
• Can be read by humans and computers alike

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Uses:

• Account numbers on cheques

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Advantage:

• Magnetised ink means characters are more likely to be read accurately

• Input device that detects physical quantities
• This includes heat, light, sound and movement
• Quantities are converted into electrical signals

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Uses:

• Measuring temperature
• Measuring humidity

• Input achieved by pressing on the screen
• Used when there are a finite number of possible choices
• User is restricted to what is available on the screen

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Uses:

• ATM Machine (cash machine)