When we work with computer we need to enter data and instructions to the computer using some devices. These devices are called input devices. These devices convert data and instructions to a form that can be recognized by the computer. Some of the commonly used input devices are : Keyboard Mouse Scanner Joystick Microphone Digital camera
Input devices are things we use to put information into a computer.An input device is any hardware device that sends data to thecomputer, without any input devices, a computer would only be a displaydevice and not allow users to interact with it, much like a TV.For example, a keyboard is an input device.Input devices other than the keyboard are sometimes calledalternate input devices.Mice, trackballs, and light pens are all alternate input devices.In the picture to the right, is a Logitech trackball mouse is anexample of an input device.
Input Devices & Their Uses Input devices are necessary to convert our information or data in to aform which can be understood by the computer. A good input device should provide timely, accurate and useful data to themain memory of the computer for processing followings are the most usefulinput devices. If the hard drive, RAM and processor are the brains of a computer, theinput devices such as the keyboard, mouse and microphone are its eyes andears, feeding the computer information and telling it where to focus itsattention. Without input devices, a computer is a brain with nothing to think about. But combined with memory and processing power, they make computerssome of the most valuable pieces of equipment in our lives.
The PC’s keyboard is theprimary human input device on thesystem. In other words, The keyboardis the primary input device for mostsoftware, so learning how to programthe keyboard properly is veryimportant to application developers. Most modern keyboardsprovide at least 101 different keys.
The keyboard is an input device designed toenter text, characters and other commands into thecomputer. The keyboard is a way to input letters ornumbers into different applications or programs. A keyboard also has special keys that helpoperate the computer. The keyboard is the primary way of enteringtext in a computer, although it may be replaced byhandwriting and speech recognition programs in thefuture. It look like a typewriter and is used for keyentry of data into a computer. Keyboards are used to enter data to orderfulfilment systems and to interact with electroniccatalogs. Most actions you can perform with your mousecan also be performed with your keyboard.
Microsoft, Logitech etc. Modern computer keyboardswere modelled after, and are stillvery similar to, classic typewriterkeyboards. Many different layouts areavailable around the world but mostkeyboards are of the QWERTY type. Keyboards may be wired orwireless but they alwayscommunicate with the computervia PS/2or USB connections, usuallylocated on the motherboard. Even though the keyboard sitsoutside the main computer housing,it is an essential part of the completesystem.
COMPUTER KEYBOARDS SHARE MANY SIMILARITIES TO ANDSOME DIFFERENCES FROM A TYPEWRITER KEYBOARD. Alphabet layout is basically the same. The location of some punctuation keys is different Additional keys include directional keys and the number pad on the right.THE BASIC HAND PLACEMENT ON A KEYBOARD TAKES SOME PRACTICE. Rest both thumbs on the space bar. Starting with the little finger of your left hand on the letter “A”, the other three fingers will rest on the next three letters “S” “D” and “F”. Skip “G” and “H” and put index finger of your right hand on the “J” key. The other three fingers of your right hand will rest on “K” “L” and the semicolon key. Notice how you can reach all the other keys quite easily. Hunting and pecking is good, too. Use whatever is most comfortable to you!
THE BASIC HAND PLACEMENT ON A KEYBOARD TAKES SOMEPRACTICE. ESC-ESCAPE KEY (In DOS and Windows environments, pressing the Escape key usually cancels or aborts the current operation.) Space bar TAB moves the document over a set number of spaces BACKSPACE backs over the document erasing as it goes. ENTER is a multipurpose key and will either allow you to enter information on the computer or act as a return carriage key on a typewriter. Forward slash vs. back slash.
THERE ARE SEVERAL SPECIALTY KEYS ON THE KEYBOARD THATWILL HELP WITH FORMATTING YOUR TYPING AND MAKE SOMECOMPUTER STEPS FASTER. MANY CAN BE USED IN COMBINATIONWITH OTHER KEYS TO CREATE SHORTCUTS FOR SPECIAL ACTIONS. ARROW KEYS will move you anywhere within a document without making any changes. HOME/END PAGE UP/DOWN INSERT/DELETE Number/directional pad with NUMLOCK on and off Multiple key commands-Many people find it less efficient to have to take their hands off the keyboard to click buttons with the mouse so there are keyboard shortcuts using two or more keys together (See the Keyboard shortcuts hand-out) You use both the SHIFT key and the CAPS LOCK key to create upper case letters.
A graphics tablet is a computer input device thatenables a user to hand-draw images andgraphics, similar to the way a person draws imageswith a pencil and paper.These tablets may also be used to capture data orhandwritten signatures.It can also be used to trace an image from a pieceof paper which is taped or otherwise secured to thesurface.Capturing data in this way, either by drawing orentering the angles of linear poly-lines or shapes iscalled digitizing.The device consists of a flat surface upon which theuser may "draw" or touch an image using an attachedstylus, a pen-like drawing device.The image generally does not appear on the tabletitself but, rather, is displayed on the computermonitor.
The first electronic handwriting tablet was the Telautograph, patented by ElishaGray in 1888. The first graphics tablet like modern tablets and used for handwriting respect bya computer was the Stylator in 1957. The first digitizer tablet is the RAND Tablet and introduced in 1964. The acoustic tablet, or spark tablet, used a stylus that generated clicks with aspark plug. The first home computer graphics tablet was the KoalaPad. In 1981, musician Todd Rundgren created the first color graphics tabletsoftware for personal computers, which was licensed to Apple as the Utopia GraphicsTablet System. In the 1980s, several vendors of graphics tablets began to include additionalfunctions, such as handwriting recognition and on-tablet menus.
PUCK After styli, pucks are the most commonly used tablet accessory. A puck is a mouse-like device that can detect its absolute position androtation. Most tablet drivers are capable of allowing a puck to emulate a mousein operation, and many pucks are marketed as "mice". EMBEDDED LCD TABLETS Some graphics tablets incorporate an LCD into the tablet itself,allowing the user to draw directly on the display surface. Graphics tablet/screen hybrids offer advantages over both touchscreens and ordinary tablets. Unlike touch screens, they offer pressure sensitivity, and theirresolution is generally higher.
•Graphic tablets can be used in place of a mouse.•They use the fluid motion and natural positioning ofthe human hand to its best advantage.•Using a graphic tablet is as easy and as comfortableas using a pen, pencil or airbrush. GRAPHIC TABLETS CAN BE USED AT SUCH FIELDS:•Illustrators, Animators, Photographers & GraphicDesigners.•Industrial Design, Architects & Engineers.•Medical & Healthcare.•Education & Training.•Business & Office.•Geographic Information Systems Mapping & ControlSystems.
INTRODUCTION TO THE MOUSE: A computer mouse is aninput device that is most often used witha personal computer. Moving a mouse along a flatsurface can move the on-screen cursor todifferent items on the screen. Items can be moved or selectedby pressing the mouse buttons (calledclicking). It is called a computer mousebecause of the wire that connects themouse to the computer. The people who designed thefirst computer mice thought that itlooked like the tail on a mouse. Today, many computer mice usewireless technology and have no wire.
FORMAL DEFINITION AND INTRODUCTION: A mouse is an external computer hardware device. It allows a user to control the motion of a computer cursor. It also select objects on the screen by moving and clicking the device. During the 1980’s, computer mice became the dominant way for people to interface with personal computers after testing with various devices showed it to be the most convenient and simple to use. The mouse works on the basic principle that the movement of the device is translated into the movement of the cursor on the screen.
Parts of Mouse:1. Top Casing2. Right‐Click Cover Plug3. Left‐Click Cover Scroll Wheel4. Scroll Wheel5. Connecting Wire/Cord Left‐Click Cover6. Plug Connecting Wire7. Bottom Casing8. Track Ball Right‐Click Cover9. Internal Circuit Board Top Casing
On most computers, the user can movethe mouse to move the cursor in the samedirection. If there is something on the screen thatthe user wants to choose, he can move the cursorover it and "click" the mouse button. The right mouse button is used to openmenus that are different depending on where thecursor is.The other mouse buttons can do differentthings, depending on the software. A mouse can have 1 to 6 buttons to click,but most mice have two or three. Most mice alsohave a "scroll wheel" -- a small wheel foundbetween the two main mouse buttons. The user can move the wheel up or downto "scroll" through things like a website or folder,which means to move it up or down on the screen,or he or she can click the wheel down like anotherbutton.
A scanner is a device that captures imagesfrom photographic prints, posters, magazine pages, andsimilar sources for computer editing and display.Scanners come in hand-held, feed-in, and flatbed typesand for scanning black-and-white only, or color. Very high resolution scanners are used forscanning for high-resolution printing, but lower resolutionscanners are adequate for capturing images for computerdisplay. Scanners usually come with software, such asAdobes Photoshop product, that lets you resize andotherwise modify a captured image. Scanners usually attach to your personalcomputer with a Small Computer System Interface (SCSI ). An application such as PhotoShop uses theTWAIN program to read in the image. Some major manufacturers of scanners include:Epson, Hewlett-Packard, Microtek, and Relisys.
A scanner is used to input paper documents orphotos into the computer. They are typically "scanned" as images (likepictures) and stored in TIFF, GIF, or JPG format, and canalso be scanned into the Portable Document Format (PDF),or converted to text using Optical Character Recognition(OCR).THE MANY USES OF A SCANNER: One of the most useful inventions to come alongwith the computer age is the scanner. Unlike a photocopier which simply makes a copyof an article, a scanner allows you to preserve a digitalimage of just about anything you can fit on a scanner bed.
COPYING DOCUMENTS - You can turn a good flatbed scanner into a copying machineby scanning in those receipts and other important documents and then use your printerto have a copy or just keep a digital copy.SCANNING PHOTOS FOR PRINTING - Photographs are nice especially if you are aprofessional photographer, but you could use the photos for websites to display yourlatest DIY project. The images could be used for desktop wallpaper or sending tofriends and family through email. Because they are digitized you can use computersoftware to edit them, and make interesting images on top of the first.FAXING DOCUMENTS - You can Fax a document that is already in your computer,but if that document is on a sheet of paper, you have a problem. A scanner can scan itin, then you can send it out by using the fax driver.OCR - Optical Character Recognition (OCR) software is used to convert images toreadable text. OCR software usually comes with the scanner.
ADVANTAGES The advantages of using scanners are: It can copy things ontocomputers then you can alter the things you copied. Flatbed scanners are very accurate and can produce reasonablyhigh quality images Any image which is digitised by the scanner can thenbe included on electronic documents Images once digitised can beenhanced with a graphics application. DISADVANTAGES The disadvantages of using scanners is that if there is ablackout, the whole system goes out. Images can take up a lot of memory space Images lose somequality in the scanning and digitising process The quality of the finalimage is dependent on the quality of the original image.
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