INPUT DEVICES
Input devices are those peripheral devices that are used to supply input to the computer. An input device converts input into suitable binary form that can be accepted by the computer.
The data entered through the input devices can be text, graphical image/symbol, audio, video etc. Depending on the form of the data the various input devices are available.
KEYBOARD KEYS
The data entered through the input devices can be text, graphical image/symbol, audio, video etc. Depending on the form of the data the various input devices are available.
- KEYBOARD
KEYBOARD KEYS
- NUMERIC KEYS
- CHARACTER KEYS/ALPHANUMERIC KEYS
- PUNCTUATION KEYS
- FUNCTION KEYS
- SPECIAL PURPOSE KEYS
- CURSOR MOVEMENT KEYS
MOUSE
Mouse is another popular input device used with modern computer. It is basically a pointing device, which is used to provide input in graphic-user interface operating systems. The mouse is represented on the screen in the form an arrow. This arrow is called a Cursor. Moving the mouse on your desk will move the arrow on the screen. A mouse allows us to create graphic elements on the screen, such as lines, curves and free hand shapes etc.
FUNCTIONS OF MOUSE
The main goal of any mouse is to translate the motion of your hand into signals that the computer can use. There are five simple techniques to use the mouse:
CLICK
To click on something with a mouse means to move the pointer or cursor to the item on the screen and to press and release the mouse button once.
DOUBLE CLICK
Press and release the mouse button twice in rapid succession.
DRAG
After positioning the mouse pointer over the item, then press the button and hold it down as you move the mouse.
RIGHT CLICK
Right click means to press the right button of mouse once without moving it. It helps to display a shortcut menu.
SCROLL
Scrolling is the property of mouse by which it can scroll the window vertically. A third button, called the scrolling button, does it.
Mouse is another popular input device used with modern computer. It is basically a pointing device, which is used to provide input in graphic-user interface operating systems. The mouse is represented on the screen in the form an arrow. This arrow is called a Cursor. Moving the mouse on your desk will move the arrow on the screen. A mouse allows us to create graphic elements on the screen, such as lines, curves and free hand shapes etc.
FUNCTIONS OF MOUSE
The main goal of any mouse is to translate the motion of your hand into signals that the computer can use. There are five simple techniques to use the mouse:
CLICK
To click on something with a mouse means to move the pointer or cursor to the item on the screen and to press and release the mouse button once.
DOUBLE CLICK
Press and release the mouse button twice in rapid succession.
DRAG
After positioning the mouse pointer over the item, then press the button and hold it down as you move the mouse.
RIGHT CLICK
Right click means to press the right button of mouse once without moving it. It helps to display a shortcut menu.
SCROLL
Scrolling is the property of mouse by which it can scroll the window vertically. A third button, called the scrolling button, does it.
TRACKBALL
- A trackball is a computer cursor control device used in many notebook and laptop computers.
- It is a specific style of computer mouse that allows the user to keep their hand and arm in one place, while manipulating a ball that moves the on-screen pointer.
- This input device is used in multimedia systems.
- It is a pointing device similar to the mouse except one difference that in trackball, the ball is fixed in a container that is placed on the desk. Fingers are used to rotate the ball and thus the cursor.
JOYSTICK
- Joystick is another pointing device that has been designed to play games on the computer.
- It consists of a small vertical lever mounted on the base that is used to steer the screen cursor around. Leaver moves in all directions and controls the movement of a pointer.
- The joystick can be moved left/right, forward / backward.
- A joystick contains various buttons for various functions. The functioning of these buttons differs in different games.
LIGHT PEN
- Light Pen is another pointing device that can be directly used to draw lines on the screen.
- The light pen contains a photocell that is placed on the pen shaped tube. Whenever this cell is brought closer to the screen, it senses the light coming from the screen and it generates the electrical pulses. These pulses are transmitted to a signal processor that identifies the particular pixel of the monitor, where the pen is touching.
- The light pen can be used to select items on the display or to draw on the display.
- The light pen is used for correction in architecture design, data collection, digital signature and computer-aided-design (CAD) applications.
TOUCH SCREEN
- Touch screen is a special input device, which only needs a finger touch to supply input to the system, rather than typing on a keyboard or pointing with a mouse.
- Touch screens or touch screen panels are display overlays which have the ability to display and receive information on the same screen.
- Touch screens are the monitors with a special pressure sensitive screen that detects the touch of a finger on a particular point of screen.
- A typical application of touch screen is for selection of processing options that are represented with graphical icons.
OPTICAL MARK READER (OMR)
- OMR is an input device, which reads presence or absence of a mark made with pen/pencil.
- They are basically used in checking results of multiple choice test in which the answer are marked on a special pre-printed test scoring sheet by darkening a small square or circle by a pen/pencil to indicate the correct answer.
- Optical Mark Readers are very economical devices and can read up to 10000 documents per hour.
- OMR’s process huge volumes of data in a very short span of time.
MAGNETIC INK CHARACTER RECOGNITION (MICR)
- Magnetic Ink Character Recognition is a character recognition system that uses special ink and characters.
- When a document that contains this ink needs to be read, it passes through a machine, which magnetizes the ink and then translates the magnetic information into characters.
- MICR technology is used by banks. Numbers and characters found on the bottom of checks are printed using Magnetic Ink.
- MICR provides a secure, high-speed method of scanning and processing information.
BARCODE REACER
- Barcodes are made up of bars of different widths that convey numeric information about the products.
- Barcodes reader is a type of handheld scanner that is widely used to read the barcodes printed on products. By reading a barcode, all the required information about a product is directly transferred into computer. This way, there is no need to type the name, price, size and weight of the product.
- A barcode reader works by directing a beam of light across the bar code and measuring the amount of light that is reflected back. The scanner converts the light energy into electrical energy, which is then converted into data by the decoder and forwarded to a computer.
- A barcode reader consists of a scanner, a decoder and a cable used to connect the reader with a computer.
SCANNER/IMAGE SCANNER
- Scanners are very popular input devices. They are mainly used to transfer printed or handmade pictures, photographs and text-document into computer.
- It simply translates a paper document into digital image format that can be stored in a computer. The stored images can even be altered and manipulated in interesting ways, if the computer has image-processing software.
- Every scanner has a variety of specifications, including resolution, color depth and speed. These specifications will help you determine the best use for the scanner.
- Scanners usually come with software, such as Adobe’s Photoshop product, that lets you resize and otherwise modify a captured image.
- Some major manufacturers of scanners include: Epson, Hewlett-Packard and Microtek.
- Flatbed Scanner.
- Hand-held Scanner.
- A Flatbed scanner is like photocopy machine consisting of a box having a glass plate on its top and a lid that covers the glass plate. A document to be scanned is placed upside down on the glass plate. A light source, situated below the glass plate once activated, moves horizontally from one end to another. After scanning one line, the light beam moves up a little and scans the next line. The process is repeated for all the lines.
- A handheld scanner is a small manual scanning device which is moved over the object that needs to be scanned.
- It has a set of light emitting diodes (LED) encased in a small case that can be held in hand easily. To scan a document, the scanner is dragged slowly over it from its one end to the other end with its light on.
SMART CARDS
- Smart cards are electronic cards, which are small in size and made of some plastic material with an embedded computer chip that store and transacts data between users.
- They are used to make a direct entry into the computer system.
- These cards are read by card reader, which normally acts as a scanner. This device is used to read the data encoded on electronic card and transfer it to the computer for further processing.
- Nowadays, these cards are quite common. They are used to make phone calls, pay bills and perform other common activities. The electronic card readers are also installed in common public places like-banks, universities, stores, restaurants and so on.
DIGITAL CAMERAS
- Digital Cameras are the latest type of cameras, which records and stores photographic images in digital form. These pictures can be easily transferred to computers at any time.
- Many current models of digital cameras are also capable to capture sound or video, in addition to still images. They are equipped with qualities like high resolution and zooming.
- Capture is usually accomplished by use of a photo sensor, using a charged coupled device (CCD).
- The number of photographs that a camera can shoot depends on the memory capacity of the camera.
MICROPHONES
- Microphone is the commonly used audio input device in computers. It is used to amplify or record the sounds using computers.
- These are the devices that transfer sound inputs to the computer.
- Microphone is connected to the sound input socket of the sound card of computers.
- Modern motherboards have in-built sound chips. In such case, the microphones are attached to the motherboard.
- Microphones are becoming very common due to the trend of chatting and video conferencing.
INFRARED REMOTE
- An Infrared remote is used to interact with various computer devices without using any wire.
- It is similar to the remote that you use to change the channels or increase the volume of a television.
- These remotes communicate by using infrared beams. The devices are having infrared sensors that understand these commands.
- Infrared remotes are ideal when you want to move around, while presenting a show with multimedia projector. Most of the LCD projectors are equipped with infrared remotes.
GRAPHIC TABLETS/DIGITIZER
- A graphics tablet or digitizer is a computer peripheral device that allows for a relatively simple method of inputting hand-drawn graphics or art into a computer in real time.
- Graphic designers mainly use graphics tablets to create and edit line art pictures.
- It contains a pressure sensitive pad a pen that is attached to the system unit.
- It consists of a flat surface called graphic tablet which may be kept on a table. The graphic tablet has an associated styles or cursor. Most digitizers use an electrical sensing mechanism to measure the position of the stylus on the tablet. This position is converted into a set of X and Y coordinates data.
- When the stylus is moved, a cursor on the CRT screens moves simultaneously to provide visual feedback.
- These can be used as an input device where drawings are required from end users.
Write by Ditender Singh and
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