INPUT DEVICES

INPUT DEVICE: An input device is an electromechanical device that accepts data from user or outside world and translate them into a form a computer can interpret. Ex-

Keyboard: A standard desktop keyboard is the most common input device. It is mainly used to type term and to send the instructions to a computer with the help of keys. Keyboard keys are the buttons that represent alphabets, numeric, alphanumeric and special characters. The key can be used individually or in combination with other keys. The keyboard normally contain 100 to 108 keys.

        Depending on the position or placement of the keys, the layout of a keyboard comes in various styles such as QWERTY, QWERTZ, AZERTY and DVORAK. QWERTY keyboard is the most commonly used keyboard. It is based on the English language name is derived from the sequence in which six alphabetical keys are positioned on the upper line of the keyboard. AZERTY type keyboard is mostly used in France (‘A’ and ‘Z’) Characters replace ‘Q’ and ‘W’ on such keyboards). QWERTZ type keyboard is widely used in Germany and Central Europe.

•    Keyboard was invented by Christopher Latham Sholes.
•   In Laptop, Notebook or Tab keyboard is referred as ‘Keypad’.

MOUSE

Mouse is a hand-held device which is used on a flat surface and is represented as a pointer on the screen The Pointer on the screen moves when the mouse is moved by the user. A mouse generally consists of two buttons and a scroll wheel on its top.

By pressing (clicking) the buttons of the mouse, the user gives instructions to the computer.

•     The mouse was unvented by Douglas Engel Bart.

JOYSTICK

Joystick is a pointing device whose function is similar to a mouse, except that a mouse pointer stops moving on the screen as soon as the user stops moving it, but in a joystick, the pointer continues to move in the direction towards which the joystick has been pointed. To stop the pointer, the user has to bring the joystick to its upright position. It is generally used to play video games.

SCANNER

A scanner is a device that scans a document by sensing the reflection that is received when the scanner emits rays on the contents. It takes the image of contents and converts it into a digital file.The scanned image or photo can be stored in a computer and easily transferred so a secondary storage device.

Scanner can be categorized as ‘Hand held scanner’ and ‘Flatbed scanner’.

Optical Mark Reader: OMR is an input device which can detect the marks on a paper. It is used to evaluate answer sheets in which selected answers are in dark circles or boxes. It is used to read the given or marked answers by sensing the marks made on the answer sheet.

Optical Character Reader/Recognizer: OCR is a device which not only detects a mark but can also recognize shapes and identify the characters directly from the source document. An example of OCR application can be seen in the verification of examination forms in different educational institutions.

Magnetic Ink Character Reader: MICR is a device is used by banks for processing of cheques by interpreting information stored in MICR code. On the cheques, the code of name of the bank, branch code and cheque number are printed with a special kind of ink containing magnetic particles or iron oxide which is scanned, read and identified with the help of MICR and transaction is accordingly processed in the computer. A MICR code consist of nine (9) digits.

•   On the back of Credit/Debit card, there are thin brown stripe (known as Magnetic Stripe). Such stripe contain coded information in the form of magnetic marks and are read when the card inserted into ATM.

BAR CODE READER: Bar Code Reader is a popular scanning device which reads the bar codes. Bar codes comprise if adjacent vertical black bars of different width.

        Bars are codes that represent different numbers. One can see the bar code on the back cover of this as well. A bar code reader emits a beam of light (Leaser Beam), which reflects with the bar code image. A light sensitive detector is present in the bar code reader which identifies and reads the bar code image. Once it is identified, the bar pattern is changed into numeric code which is processed inside the CPU.

Light Pen: A ‘Light Pen’ is a pen like device which uses a light sensitive detector to select or draw objects on the display screen. It is similar to a mouse, except that with a light pen one can move the pointer on the screen by making it touch the object on the screen. When the pen is moved across the screen, its position in sensed because of the light emits. A tablet PC is slate shaped notebook computer. Its technology allows the user to operate the computer with stylus, digital pen or fingertip, instead of using a keyboard or mouse.

Microphone: Microphone is a voice based input device. With the help of this device, sound or voice is recognized/recorded in the computer which is then processed inside the computer and is converted into digital form.

Digital Camera: Digital camera catches an image or picture momentarily and converts the image directly into digital form and stores in memory, which can then be read on the computer. It is available in various models with different specifications that include pixels, sixes and memory. The quality of image captured by digital camera is measured in pixels.

Web Camera: A web camera or webcam is a type of video camera that saves its recorded image in real time into a computer or computer network via USB, Ethernet or Wi- Fi. Common web camera is used in the establishment of video links, permitting computers to act as video phones or video- conference station. It has also become a source of security, as some built-in webcams can be remotely activated from far off locations.

•  Biometric Sensor is a device which captures unique information from human body. The unique information could be fingerprints, iris pattern, etc. It stores and compares the information from the available database.