Input Devices
An input device is a hardware component of a computer system that provides data and control signals to a computer. The input device provides a computing environment through which the user can interact with the system and allows the computer to do tasks as instructed by the user. A computer system sits idle if no data and instruction are fed to it. So, an input device acts as a communication channel between user and the computer and provides data and instructions to computer to perform a specific task. The examples of input devices are keyboards, mouse, joystick, scanner, digital camera, microphones, etc.
Keyboard
A keyboard is the most commonly used input device on a personal computer. It contains a set of keys that are pressed to interact with the computer. The keys in a keyboard are like electrical switches. Each key is assigned a different binary pattern and hence, sends a different signal to the CPU when it is pressed. Before keyboards came into use, punched cards and paper tapes were used as input devices to establish interaction with computers. A keyboard resembles a typewriter. Most of the keyboards have a QWERTY Layout. These keyboards have Q,W, E, R, T, and Y on the top row of letters.
A standard computer keyboard typically contains 101 or more keys. The keyboards so far developed can be of three types as:
- XT Keyboard (83 Keys)
- AT Keyboard (84 Keys)
- Enhanced Keyboard or Multimedia Keyboard (101 keys or more)
Mouse
A mouse is an input device. It is a popular pointing and selecting device used in GUI based computing environment. It is moved around on a flat surface to control the position of the pointer on the screen. A mouse can be used to select the text, access menus; and interact with programs, files, or data. Generally, a mouse has two buttons called the left button and the right button and a wheel is present in between the buttons. The buttons are used for clicking objects on the screen and the wheel is used to scroll through documents and webpages in a more easy way. There are different types of mouse. A mechanical mouse consists of a ball underneath and controls the pointer on-screen with the rolling of the ball when the device slides across a flat surface. Another type of mouse is an optical mouse whichtracks the mouse position using an optical sensor. Today, computer mouse also uses wireless technology to get conected to a personal computer.
Scanner
A scanner is also called an image scanner, is an input device. It uses optical technology to capture printed images (or sometimes text) and transfer them into a computer in the form of digital images. The digital images can be later on viewed on a monitor screen, saved, edited, emailed, or printed. The operation of a scanner is similar to a photocopy machine.
Trackball
A trackball is a pointing input device. It likes an upside-down mouse that has a moveable ball on the top. The user rolls the ball with the help of an index finger or thumb to move the cursor around the screen. Unlike the mouse, the whole device is not moved. Thus, a trackball requires less space than a mouse. The trackball contains two or three buttons for further input actions. It is generally used in portable computers such as laptops and notebooks.
Touchpad
Touch pad is designed with a tactile sensor. It is a touch-sensitive surface that can detect and translate the movement of a finger to direct and control the position of the pointer on the computer screen. A track pad also contains two or three buttons that functions as similar to mouse buttons. Touch pads are used as a substitute for a computer mouse in laptops and notebooks.
Joystick
A joystick is also a pointing input device. It consists of a stick or a handle that pivots on a base and sends its angle or direction of movement as data signals to the computer. A joystick is often used to control objects in computer games. It is also used in flight simulators, controlling machines such as cranes, trucks, surveillance cameras, industrial robots, and many more. Many video gaming joysticks also contains buttons and triggers that can provide additional instructions to the computer in controlling on-screen characters and objects.
Light Pen
A light pen is a light-sensitive, pen-shaped input device that is wired to a video terminal. It is used to select a displayed menu item or draw pictures directly on the monitor screen. It has a light-sensitive diode which senses light emitted by the Cathode Ray Tube. The light emitted from the screen causes the photocell to respond by generating a pulse. This electric response is transmitted to the processor that identifies the position to which the light pen is pointing to.
Bar Code Reader (BCR)
Bar Code Reader is also known as Point-of-Sale (POS) scanner, is input hardware that is capable of capturing and reading the information contained in bar codes. It analyzes bar codes and converts them into electrical pulses which are then sent to the computer for further processing. A bar code is a machine-readable code in the form of parallel vertical lines of varying widths printed on the products. The bar code contains information about the product like the price, date of manufacturing and expiry, name of the manufacturer, etc. encoded into it. Such bar codes are read and fed to the computer using a bar code reader.
Digital Camera
A digital camera is used to capture still images and videos, and store them in a memory card digitally. The digital camera can be connected to a computer directly with a cable, slotting memory card into the computer, or through wireless data transfer methods such as Bluetooth. After successful connection, the photographs and video files can then be transferred to the computer which can be saved, edited, printed, embedded in a document or transmitted to another user via Internet
Microphone
A microphone is an audio input device. It captures audio or sound and sends it to the computer in a digital format. The sound in digital format can be stored in secondary storage devices, played back, copied, edited, emailed, or uploaded. It is widely used in recording or speech, adding narration to the multimedia presentation, mixing music, and in audio and video conferencing over the Internet. Microphone has a great role to play in Voice User Interface (VUI) where people and devices use voice for interaction among them.
Graphic Digitizer or Graphic Tablet
Graphic Tablet is also known as digitizer, drawing tablet, drawing pad, or pen tablet. It is pointing input device that is used for converting hand-drawn images or signature into digital images. It consists of a flat surface on which the User can draw with help of a stylus or a pen-like device, similar to the way a person draws images on a paper with the help of a pencil. The drawing on the drawing pad appears live on the monitor screen as it is created which can then be saved, edited, or printed. It is generally used in drawing sketches, pictures by artists, and in Computer-Aided Design (CAD).
Touch Screen
Touch Screen is a touch-sensitive display screen that serves as an input device. It resembles a touchpad with a touch-sensitive screen placed on top of it. It allows users to provide input or control the system by touching the screen with fingertips or a stylus. Users can explore different features of an information system by moving and tapping directly on its touch screen with the help of fingers or a stylus. Many portable computers such as laptops, notebooks, handheld computer, and smart phones are equipped with a touch screen.
Optical Mark Recognition (OMR)
OMR is a type of optical scanner that is used to recognize and read a pre-specified mark made by pen or pencil on specially printed paper forms. It is specially used for checking multiple-choice questions. Students mark the correct alternative(s) on specially printed sheets using a pen or pencil as instructed. The sheets are then collected and fed to OMR. The OMR reads and recognizes the predefined marks and the data are fed to the computer for further analysis and processing.
Optical Character Recognition (OCR)
OCR is an optical scanner that is capable of recognizing characters and text from handwritten, scanned, or printed documents. OCR scans the documents and stores it as a bitmap image in the computer's memory. It then translates this bitmap image into ASCII codes so that the computer can interpret as letters, numbers, and special characters.
Magnetic Ink Character Recognition (MICR)
MICR is an optical scanner that is generally used in banks to process a large number of cheques every day. The bank's code number and cheque numbers are printed on the cheques with a special type of ink that contains particles of magnetic material. Such magnetic inked-characters are read with MICR and fed to the computer for further processing.
Web Camera
Web camera is an image and video input device that serves similar function as a digital camera. Unlike digital camera, it cannot operate independently from a computer. It is either inbuilt into the computer as in laptops and notebooks or is connected to the computer through a USB port. Webcam can capture photographs and videos and are mostly used to live-stream videos or facilitate video chats.
QR Code Scanner
The advanced form of Bar Code Reader (BCR) is OR Code Scanner. QR code stands for Quick Response Code. It contains a matrix of dots. It can be read and processed by a smart phone ora cell phone with the help of Apps or Applications. A QR code is a pattern of black and white squares. The QR code of any product gives information about website address. It is made of only alphanumeric characters; a single QR code can hold up to 4000 characters. These codes are commonly used for holding data such as simple text, addresses, phone numbers, email addresses, links to apps, payments, etc.
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