Input Devices

Input Devices:

The medium through which we can feed our data or instructions to the computer to perform several tasks is known as Input Devices. Input Devices are necessary to convert our information or data in to a form which can be understood by the computer.

Types of Input Devices are as follows:

KeyBoard

1. Keyboard

This is the standard input device attached to all computers. The layout of keyboard just like the traditional typewriter of the type QWERTY. It also contains some extra command keys and functions keys. It contains a total of 101 to 104 keys. Combination of keys should be pressed to input data. The computer can recognize the electrical signals corresponding to the correct key combination and processing id done accordingly.

Mouse

2. Mouse

Mouse is an input device that is used with personal computers. It rolls on a small ball and has two or three buttons on the top; When the rolling the mouse across a flat surface the screen censors the mouse in the direction of mouse movement. The cursor moves very fast with mouse giving more freedom to work in any direction. It is easier and faster to move through mouse.

Scanner

3. Scanner

A scanner is and input device that transfers information from a piece of paper into a computer. To do this, the scanner sends a beam of light to the page and then measures the amount light reflected back, white reflects all the light , black reflect not light, ad each color reflects different amount of light. The amount of light for each portion is given a digital code which is sent to the computer. A document is laid face down on the glass. The light moves backwards and forwards.

MICR

4. Magnetic Ink Character Recognition (MICR)

MICR is a form of character recognition that reads text printed with magnetically charged ink, determining the shapes of characters by sensing the magnetic charge in the ink, once the shapes have been determined, character recognition methods are used to translate the shapes into computer text. A familiar use of the is form a of character recognition is to identify bank cheques.

5. Optical Character Recognition (OCR)

OCR

Optical Character Recognition is the ability of a machine to recognize characters. The machine, called a scanner, uses light, or optics, to read text from a piece of paper, special software compares the pattern of the signals sent from the scanner to patterns held in memory. When a match is made, a signal is sent to the computer. Optical character recognition depends on the computer matching two patterns.

OMR

6. Optical Mark Recognition (OMR)

Optical Mark Recognition is a type of input device that reads hand-drawn marks such as small circles or rectangles. A person places these marks on a form, such as a teat, survey or questionnaires, answer-sheet. It can read information in the form of numbers or letters and put in to the computer. The marks have to be precisely located as in multiple choice test papers.

Track Ball

7. Track Ball

A trackball is an input device, another pointing device used to move the cursor. It is a ball which is rotated by the user’s finger. Trackballs may be on the keyboard, or plug into the computer separately. A trackball moves the cursor in the direction the ball is moved.

Joystick

8. Joystick

Joystick is a pointing device, one of the input devices that are used to move the cursor on the screen. It has a stick with balls at its upper and lower ends. We can move the stick in different directions like from left to right to forward or backward. Joystick is mostly used while playing computer games.

9. Digital Camera

Camera

It is a type of camera that stores photographed images electronically instead of on traditional film. A digital camera uses a CCD(Charge-coupled device) element to capture the image through lens when the operator release the shutter in the camera; circuitry within the camera then stores the image captured by the CCD in a storage medium such as solid-state memory or a harddisk. After the image has been captured, it is downloaded by cable to the computer using software supplied with the camera. Once stored in the computer, the image can be manipulated and processed much like the image from a scanner or related input devices.

10. Bar Code Reader

Bar Code Reader

Bar Code Reader, also called as bar code scanner is a input device that uses laser beams to read bar codes on products such as groceries, books and packages.

Light Pen

11. Light Pen

Light pen is used as pointing device, which is very sensitive to light. Light pen uses a photoelectric (light-sensitive) cell to communicate the screen position to the computer. When the light pen tip is places against the screen, it is capable of sensing its position on the Cathode Ray Tube (CRT). As the tip of the pen is moved over the surface of the screen, its light sensitive elements detects the light emitted from the screen. We can select the desired option of the menu by touching light pen against desired option. Now days, light pens are used in menu big hotels room for the customer for selecting their choice of menu and other items.

Touch Screen

12. Touch Screen

This is easiest way to enter data using the finger touch. Touch screens enable the user to select an option by pressing a specific part of the screen. Touch screens are commonly used in grocery stores, fast food restaurants, and information centers.

Touch Pad

13. Touch Pad

Many laptop computers use a touchpad in front of the keyboard. We move our finger on the pad to move the cursor on the screen. When we want to click, we can tap pad or use the buttons in front of the pad, which works like mouse buttons.

14. Microphone

Micro Phone

Microphone is used to give voice commands to the computer or we can chat with someone with the microphone in the internet.