INPUT DEVICESShobit goel

BBA(GEN)064

Various Input Devices

KeyboardMouseJoystickScannerMICROCROMR

Keyboard

KEYBOARDA computer keyboard is one of the

primary input devices used with a computer that looks similar to those found on electric typewriters, but with some additional keys. Keyboards allow you to input letters, numbers, and other symbols.

The keyboard has five sections 1) Typing keys 2) Numeric Keys 3)Functional keys 4)Control Keys 5) Special purpose keys

Five sections of keyboard

Typing keys (1,2,3……, A,B,C…) Numeric Keys (Numeric keys on right

side)Functional keys (F1,F2…. On top side)Control Keys (Cursor keys,ctrl,alt…) Special purpose

keys(Enter ,Space ,Shift ,Spacebar …)

Advantages of keyboards Disadvantages of keyboards

Most computers come with a keyboard supplied

It is easy to make mistakes when typing in data

People are used to using keyboards to enter data, they need very little training

If you can't touch type, it can be time consuming to enter data

A skilled typist can enter data very quickly

Keyboards are not suitable for creating diagrams

Specialist keyboards are available e.g. ergonomic, gaming keyboards

Disabled people often find keyboards difficult to use

Mouse

MOUSE

A mouse is a hardware input device that was invented by Douglas Engelbart in1963 .Mouse is a small handed device having two or three buttons on its upper side.

A mouse is classified as physical mouse and optical mouse.

Classifications of mouse

Physical mouse:- It has a rubber on the bottom side that protrudes when the mouse is moved . It requires a smooth , dust free , such as a mouse pad on which it is rolled

Optical Mouse:- It uses Light Emitting Diode(LED) and a sensor to detect the movement of mouse. Optical mouse was introduced by Microsoft in 1999.

Advantages of mouse Disadvantages of mouse

Ideal for use with desktop computers

They need a flat space close to the computer

Usually supplied as part of a new computer system

Older style mouse which have roller balls can become clogged with grease and grime and lose their accuracy until cleaned.

Most computer users are familiar with them and require little training

Excessive use can lead to health problems such as repetitive strain injury (R.S.I.)

Works well in conjunction with a keyboard for data entry

If the battery wears out in a wireless mouse, it cannot be used until it has been replaced

JOYSTICK

JOYSTICK

A joystick is an input device that allows the user to control a character or machine in a computer program, such as a plane in a flight simulator. They look similar to the control device you would find on an arcade game, but nearly always include extra buttons for additional functionality. Today, most computer joysticks connect to the computer using a USB port

Advantages of joysticks

Disadvantages of joysticks

They give a better gaming experience for racing or flying styles of computer games

Some people find joysticks more difficult to control than a traditional mouse.

 

Joysticks are not particularly robust and can break easily if too much force is used on them.

 

SCANNER

Scanner

With hardware, a scanner or optical scanner is a hardware input device for a computer. Scanners allow a user to take a printed picture, drawing, or document and convert it into a digital file (either an image or a text file) so that it can stored, viewed, and edited on a computer. A scanner can be connected to a computer using many different interfaces although today is most commonly connected to a computer using USB.

Two types of scanner are :- 1) Hand Held Scanner 2) Flat bed Scanner

Types of Scanner

Hand held Scanner:-Handheld scanners are usually only a few inches wide and are held in the hand whilst they are rolled across the document to be scanned. The images produced are generally not as large or as high quality as those captured with a flatbed scanner.

Flat-bed Scanner:- The most popular type is the flatbed scanner. This is probably the one that we use at school. They can scan larger images and are more accurate than handheld scanners.

Advantages of scanners Disadvantages of scanners

Flatbed scanners are very accurate and can produce reasonably high quality images.

Images produced by the scanner can take up a lot of memory space.

Any image which is digitised by the scanner can then be included on electronic documents.

Images lose some quality in the scanning and digitising process.

Images once digitised can be enhanced with a graphics application.

The quality of the final image is dependent on the quality of the original image .

Can accurately capture an image, but the original source may be more important than the scanned image.

 

MICR

Magnetic-Ink Character Recognition

Magnetic-Ink Character Recognition, MICR is a font capable of recognition using magnetically charged ink. Computers equipped with the right hardware and software can print or read the character printed in such ink. MICR font is commonly used to print checks, deposit slips, mortgage coupons, etc.

Advantages of MICR Disadvantages of MICR

MICR is difficult to forge. MICR readers and encoders are very expensive.

Documents can still be read when folded or written on.

The system can only accept a few different character sets.

Optical Character Reader

Optical Character Reader

Optical Character Recognition or Optical Character Reader, OCR is the process of taking an image of letters or typed text and converting it into data the computer understands. A good example is companies and libraries taking physical copies of books, magazines, or other old printed material and using OCR to put them onto computers.

Advantages of OCR Disadvantages of OCR

Cheaper than paying someone to manually enter large amounts of text

Not 100% accurate, there are likely to be some mistakes made during the process

Much faster than someone manually entering large amounts of text

All documents need to be checked over carefully and then manually corrected

The latest software can recreate tables and the original layout

If the original document is of poor quality or the handwriting difficult to read, more mistakes will occur

  Not worth doing for small amounts of text

Optical Mark Recognition

Optical Mark Recognition

Optical Mark Recognition, OMR is the process of gathering information from human beings by recognizing marks on a document. OMR is accomplished by using a hardware device (scanner) that detects a reflection or limited light transmittance on or through piece of paper. OMR allows for the processing of hundreds or thousands of physical documents per hour.

Advantages of OMR Disadvantages of OMR

A fast method of inputting large amounts of data - up to 10,000 forms can be read per hour depending on the quality of the machine used.

If the marks don't fill the space completely, or aren't in a dark enough pencil, they may not be read correctly

Only one computer needed to collect and process the data

Only suitable for recording one out of a selection of answers, not suitable for text input.

OMR is much more accurate than data being keyed in by a person

The OMR reader needs the answers to be on the prepared forms which will all be identical to one another. You can't just pick up a blank sheet of paper and mark your answers on it.