Input Devices

Input

            Anything given to the computer is called Input.

Input Devices

An input device is any peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing.

OR

The devices that are used to enter data and instructions into the computer are called input devices.
There are many types of input devices such as:

Mouse

            Mouse is an input device that looks a little bit a mouse. It has a ball on its underside that is rolled on a flat surface or mouse pad. It also has button on its top which communicates certain commands to the computer while pressed.

Mouse Events:

                        Mouse events refers to the activity that can be performed by using the mouse, a typically mouse can perform the followings events.

-          Left Click

-          Right Click

-          Drag

Left Click:

            It is used to select graphical object such as a file icon and a piece of text in a document etc. or to press a button such as the start button and closing, opening or minimizing a windows etc.

Right Click:

            It is used to view properties of an object such as file, folder, desktop etc.

Drag:

            When you keep on pressing the left mouse button while moving the mouse this event to move to select more than one item at a time.  

Keyboard

                        The keyboard looks like a typewriter keypad to which some special keys has been added. The keys normally available on the keyboards are Numeric, Alphabetic Functions and additional Special-Purpose keys.   This standard keyboard is also called “QWERTY”.

Function Keys:

                        The function keys are an easy way to give certain commands to the computer. The particular software we use defines what each function key does.

Main Keyboard:

                        The main keyboard includes the familiar keys found on a typewriter keypad, as well as some special command keys.

Numeric Keys:

                        The numeric keys serve one of the two purposes depending on the status of the Num lock key. When the computer is in the Num lock mode these keys can be used to enter numeric data and mathematical symbols (/ for “divided” by”, * for “multiplied by”, - for “subtraction”   and + for “addition”)

Keyboard has divided four parts

 

Track Ball

                   A track ball is also a pointing input device it performs functions like a mouse but it is a stationary device. it has a moveable ball on its top. The ball is rotated or rolled with fingers to control the moment of pointer on the screen. Like mouse, a track ball also has button used to send the commands to computer.

Joy Stick

                  Joy stick is also pointing device it consist of a vertical handle like a gearshift lever mounted on a base. The vertical handle is used to control the moment of pointer on the screen. It also consists of one or buttons. The buttons of the joy stick is pressed to activate certain events or actions. Joy stick is basically used to play video games. It is also used in some computer aided design (CAD) system. 

Light Pen

                  The light pen is a handle pointing input device. It is a light sensitive styles or pen like device. It is connected with the computer by a wire. When the front and of the pen is touched with the monitor screen, the photo cell detects or sense a position on display screen. This device also has a button. The user points the objects to be selected on the display screen and then presses a button on the light pen.  

OR

A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with the computer's CRT TV set or monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy. A light pen can work with any CRT-based display, but not with LCD screens, projectors and other display devices.

Digital Camera

                            A digital camera is an input device because it captures information and stores it on the device via the memory card (which is a storage device).

OR

A digital camera is an input device. It is used to take pictures in digital forms. It does not use traditional camera film. It uses a light sensitive processor chip to capture photographer image in digital form. These images are stored on a small diskette inserted in the camera or on flash memory chip. 

Touch Pad

                 Touch pad is a pressure sensitive pointing input device. Touch pad is also known as track pad. It is also stationary device like track ball but it has no moving parts. It is a small, flat surface over which we slide our finger tip to move the pointer on screen for pointing desired icons. As we slide our finger tip on the flat surface of touch pad the pointer moves on the screen. Touch pad have one or more button.