Page 12 - DCAP105_WORKSHOP_ON_COMPUTER_HARDWARE_AND_NETWORK

Workshop on Computer Hardware and Network

Notes Light Pen

Light pen is a pointing device, which is used to select a displayed menu item or draw pictures on
the monitor screen. It’s a pen shaped device allowing natural movement on the screen. The pen
contains the light receptor and is activated by pressing the pen against the display screen.
Receptor is the scanning beam which helps in locating the pen’s position. Suitable system
software is provided to initiate necessary action when we locate an area on the display surface
with the help of the light pen. It consists of a photocell and an optical system placed in a small
tube. When its tip is moved over the monitor screen and the pen button is pressed, its photocell-
sensing element detects the screen location and sends the corresponding signal to the CPU.

Figure 1.5: Light Pen

Touch Screen

Touch screen is sensitive to human fingers. Using this device, the user can point to a selection on
the screen instead of pressing keys.

Figure 1.6: Touch Screen

Game Controller

A game controller is a device used with games or entertainment system used to control a
playable character or object, or otherwise provide input in a computer game. A controller is
typically connected to a game console or computer by means of a wire, cord or nowadays, by
means of wireless connection. Controllers which have been classified as games controllers are
keyboards, mice, game pads, joysticks, etc.

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