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Computer input devices

Input devices include those devices with the help of which we enter data into computer as they make a link between user and computer. These devices translate the human readable information into the form understandable by computer. The various devices are as follows:

  1. Keyboard : Keyboard is among the most common and popular input device . It is used to input the data to the computer. In traditional times the typewriter was used. The keyboard has the layout similar to that of a typewriter but some additional keys are present that have additional functions.
  2. Mouse : Mouse is a cursor-control device . It is a pointing and drop device. It’s size is good enough to fit the palm. It has a palm size box with a round ball at its base .It senses the movement of mouse and sends corresponding signals to CPU on pressing of the buttons. There are two buttons that provide the left click and the right click. A scroll bar is present in the mid .Mouse is only used to control the position of cursor on screen.
  3. Joystick : Just like the mouse , Joystick is also a pointing device, which is used to move cursor position on a monitor screen. It has a stick that has a spherical ball at its both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in four directions. It is mainly used in Computer Aided Designing (CAD) and playing computer games.
  4. Light Pen : Light pen is also a pointing device. Its structure is similar to that of a pen. It is based on an optical system placed in a small tube. It is used to select a displayed menu item or draw pictures on the monitor screen. When light pen’s tip is moved over the monitor screen and pen button is pressed, its photocell sensing element, detects the screen location and sends the corresponding signal to the CPU.
  5. Track Ball : Track ball are used mostly in notebook or laptop computer. This is a ball, which is half inserted and by moving fingers on ball, pointer can be moved. A track ball requires less space than a mouse as the whole device is not moved. A track ball can come in various shapes like a ball, a button and a square.
  6. Scanner : Scanner is an input device, which works on a similar principle of a photocopy machine. It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation. Scanner captures images from the source which are then converted into the digital form that can be stored on the disc. These images can be edited before they are printed.
  7. Touch Screen : A touchscreen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with a special stylus/pen and-or one or more fingers. Some touch screens use an ordinary or specially coated gloves to work while others use a special stylus/pen only. The user can use the touchscreen to react to what is displayed and to control how it is displayed (for example by zooming the text size).
  8. Digitizer : Digitizer is an input device which converts analog signal from the television camera into a strings of binary digits that can be stored in a computer. It converts the analog information into a digital form. Digitizer is also known as Tablet or Graphics tablet. They can be used by the computer to create a picture of whatever the camera had been pointed at.
  9. Magnetic Ink Card Reader (MICR) : We see in banks, libraries etc using MICR as an input device . As large number of cheques are processed everyday MICR serves a very useful purpose. A special type of ink that contains particles of magnetic material that is machine readable, is used to read the code number and cheque number that are printed on the cheques in banks. This reading process is called Magnetic Ink Character Recognition (MICR). The main advantage of MICR is that it is highly accurate and fast in reading.
  10. Optical Character Reader (OCR) : OCR is an input device that is used to read a printed text. The role of OCR is to scan the text optically character by character by converting them into a machine readable code and store the text on the system. The OCR is used for the preparation of electricity bills, insurance premium, telephone bills.
  11. OMR (Optical Mark Recognition): Optical mark recognition (also called optical mark reading and OMR) is the process of capturing human-marked data from document forms such as surveys and test.
  12. SCR (Smart Card Readers): A small electronic device about the size of a credit card that contains electronic memory, and possibly an embedded integrated circuit (IC). Smart cards containing an IC are sometimes called Integrated Circuit Cards (ICCs). Smart cards are used for a variety of purposes, including: – Storing a patient’s medical records – Storing digital cash – Generating network IDs (similar to a token) To use a smart card, either to pull information from it or add data to it, you need a smart card reader, a small device into which you insert the smart card.
  13. Bar Code Readers : Bar Code Reader is a device used for reading bar coded data (data in form of light and dark lines). Bar coded data is generally used in labelling goods, numbering the books, etc .Bar Code Reader scans a bar code image by converting it into an alphanumeric values . This value is then fed to the computer to which bar code reader is connected.
  14. Microphone : A microphone,is an acoustic-to-electric transducer or sensor that converts sound in air into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systemsfor concert halls and public events, motion picture production, live and recorded audio engineering, two-way radios, megaphones, radio and television broadcasting, and in computers for recording voice, speech recognition, VoIP, and for non-acoustic purposes such as ultrasonic checking or knock sensors.
  15. Webcam : A webcam is a video camera that feeds or streams its image in real time to or through a computer to computer network. When “captured” by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an IP camera (which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops.

Published on Wed 04 April 2012 by Dale Hampton in Computer Science with tag(s): input devices