What is Input Devices?

What is Input Devices?

Input devices accept data and instructions from the user. Following are the examples of various input devices, which are connected to the computer to provide input.

There are many input devices. Some important input devices are as follows:

1.      Keyboard

2.      Mouse

3.      Joystick

4.      Light Pen

5.      Optical/magnetic Scanner

6.      Touch Screen

7.      Microphone for voice as input

8.      Track Ball

1.      Keyboard:

A keyboard is the most common input device now. Several kinds of keyboards are available, but they resemble each other with minor variations. The keyboard in most common use is the QWRTY board (from keys Q, W, E, R, T, Y in the top left corner of the keyboard). IBM and IBM compatible PCs or microcomputers use 104 keyboard; so called since it has 104 keys. In these keyboards, the cursor control keys are duplicated to allow easier use of the numeric pad.

2.      Mouse:

A mouse is an electro-mechanical, hand-held device. It is used as a pointer. It can perform functions like select menu commands, move icons, resize windows, start programs, and choose options.

The most common mouse uses an internal, magnetically coated ball, to detect the movement of the mouse across a flat surface, usually a desktop. ALL WINDOWS based applications today are designed to work with a mouse. A mouse is used to replace hard-to-remember key combinations with easier “Point and Click” actions. However, it cannot substitute all keyboard operations. It can be alternative for commands based operations.

Types of mouse

a)      Mechanical:

It has a rubber or metal ball on its underside that can roll in all directions. Mechanical sensors within the mouse detect the direction in which the ball is rolling and move the screen pointer accordingly.

b)       Optomechanical:

It is same as mechanical mouse, but uses optical sensors to detect the motion of the ball.

c)      Optical or Laser:

It uses a laser to detect the mouse’s movement. Optical mouse has no mechanical moving parts. They respond more quickly and precisely than mechanical and optomechanical mouse but they are also more expansive.]

3.      Joystick:

A joystick is a pointing device. It is basically a lever that moves in all direction and controls the movement of a pointer. A joystick is similar to a mouse in all directions and controls the movement of a pointer. A joystick is similar to a mouse, except that with a mouse the cursor stops moving as soon as you stop moving the mouse. With a joystick the pointer continues moving in the direction the joystick is pointing. To stop the pointer you must return the joystick to its upright position. Most joysticks include two buttons called triggers.

Joysticks are used mostly for computer games, but they are also used occasionally for           CAD/CAM systems and other applications. It provides more realistic control than a mouse or a keyboard for many games (e.g., flight simulators). The joystick is attached to the computer through a cable connected to the “Games port”. Most computers come with one game port. Joysticks are not used for business applications such as word- processing, data analysis (using Spreadsheet) or data management.

4.      Light pen:

An input device that utilize a light - sensitive  detector to select objects on a display screen. A light pen is similar to a mouse, except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.

5.      Optical Scanner:

These devices are used for automatic data collection. The device of this  category completely eliminate manual input of data. For example, the bar-code reader is actually just a special type of image scanner. An image scanner translates printed images into an electronic format that can be stored in a computer’s memory, and with the right kind of software, one can alter a stored image. Another example of scanner is optical character recognition (OCR) device, used by banks to convert the scanned image of a typed or printed page into text that can be edited on the computer.

6.      Touch Screen:

Touch screen panel displays and pads are now being offered as alternative to keyboard input. Here the input can be given through the computer screen, that accepts the input through monitor, users touch electronic buttons displayed on the screen or they may use light pen.

7.      Microphone:

Microphone is an input device, which takes voice as input. The voice communication is, more error prone that keyboard information.

There are two types of microphones available                                 

a)      Desktop Microphone

b)      Hand-held Microphone

8.      Track Ball:

Track ball, a pointing device, is a mouse lying on its back. To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which you use just like mouse buttons.

The advantage of trackball over mouse is that the trackball is stationary so it does not require much space to use it. In addition you can place a trackball on any type of surface, including your lap. For both these reasons, trackballs are popular pointing devices for portable computers.