Input Devices

Input devices

• purpose• entering data into a computer system

• issuing instructions (commands) to a computer

• input device• transforms data from the user into a form that a

computer system can process• together with appropriate software (device drivers)

Types of Input Devices

• Keyboard

• Light pen

• Graphics tablet

• Joysticks

• Trackball

• Data glove

• Digitizer

• Image scammer

Keyboard

• A keyboard contains keys that allow a user toenter data and instructions into the computer.All computer keyboards have a typing area thatincludes the letters of the alphabet, numbers,punctuation marks, and other basic keys.

Mouse

• A mouse is the mostwidely used pointingdevice with a GUIenvironment onpersonal computers.A mechanical mousehas a rubber ball onits underside todetect movement ofthe mouse. Anoptical mouse usesdevices that emitand sense light todetect the mouse'smovement.

Advantages

• A mouse is user-friendly for computer beginners.

• A mouse is easy and convenient to use with a graphical user interface.

Trackball

• A trackball is a stationarypointing device with a ballmechanism on its top. Atrackball is acomputer cursor controldevice used in manynotebook and laptopcomputers. The trackballis usually located in frontof the keyboard towardthe user. Essentially, thetrackball is an upside-down mouse that rotatesin place within a socket.

Graphic Tablet:

• A graphicstablet or digitizer is acomputer input device thatenables a user to hand-drawimages, animations andgraphics, similar to the waya person draws images witha pencil and paper. Thesetablets may also be used tocapture data or handwrittensignatures. It can also beused to trace an image froma piece of paper which istaped or otherwise securedto the surface. Capturingdata in this way, either bytracing or entering thecorners of linear poly-linesor shapes is called digitizing.

Data Glove

• Data Glove or wiredglove (sometimes called a"dataglove" or "cyberglove")is an inputdevice for human–computerinteraction worn like aglove.

• Various sensor technologiesare used to capture physicaldata such as bendingof fingers. Often a motiontracker, such asa magnetic tracking deviceor inertial tracking device, isattached to capture theglobal position/rotation dataof the glove

Touchpad • It is a small pressure-

and motion-sensitivearea on a portablecomputer that you canuse to move themouse pointer. Whenyou move your fingeracross the pad, themouse pointer on thescreen moves in thesame direction. Atouch pad is analternative to amouse.

Advantages of a touch pad include

• Easy and Fast one finger control.

• Ideal for portable devices

Disadvantages of using a touchpad include

• Expensive & found in specific devices e.g. laptops

Touch screen

• A touch screen is an input/output touch-sensitive display. Touch screens are often usedfor information kiosks located in departmentstores, hotels, airports, and museums. Touchscreens are also used for ATM machines toallow easy access of bank accounts.

Joystick

• A joystick is a pointingdevice with a verticallever mounted on abase. The leverusually includesbuttons calledtriggers, whichactivate certainevents when pressed.Joysticks are mainlyused for computergames andultrasound scannersin hospitals.

Light Pen

• A light pen is a pointing device that can detect the presence of light. Light pens are used by health care professionals (such as doctors and dentists) and design work. A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's CRT display.

Scanner• A scanner is a light-sensing input device that converts

printed text and graphics into a digital form that can befurther processed by the computer.

• Popular types of scanners are:

• Flatbed scanner: It works like a copy machine except thatit creates a file of the document rather than a paper copy.

• Handheld scanner: It can be manually passed over theimage to be scanned. A portable device you can use to copyan image from paper to your computer. Hand-held scannersare ideal for capturing small images, such as signatures andlogos. A hand-held scanner is smaller, less expensive, andmore portable than a flatbed scanner.