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Information and Communication Technology Applications

Figure 5.11: A Joystick
Notes

Digitizer

Digitizer is used to create drawings and pictures using a digitizer tablet by a process called digitizing.
Digitizing is a process by which graphic representations are converted into digital data. The digitizer
consists of 3 main parts—a flat surface called tablet, a small hand held mouse-like device called puck
and a special pen like device called stylus as shown in Figure 5.12. The puck is used to input existing
drawings into the computer. The stylus is used to trace existing drawings placed on the tablet. It is
also used to draw new drawings on a piece of paper placed on tablet. The user makes contact to the
tablet with stylus. As the stylus is connected to the tablet by a wire, the traced image is stored in
RAM and displayed on the monitor.

Figure 5.12: A Digitizer

Stylus
Function
buttons
Window

Tablet
Puck

Optical Mark Reader (OMR)
Optical Mark Reader is a special type of optical scanner used to recognise the type of mark made by
pen or pencil. It is used where one out of a few alternatives is to be selected and marked. It is
especially used for checking the answer sheets of examination having multiple choice questions.
The answer sheet contains special marks such as squares or bubbles. The student fills in these squares
with soft pencil or ink to indicate the correct choice as shown in Figure 5.13. The OMR detects these
marks and sends the corresponding signals to the processor. If a mark is present, the amount of
reflected light is reduced and, thus, OMR detects the presence of mark for each and every answer.
Optical Mark Readers are widely used for almost all-competitive examinations having objective
type questions.

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