input device play media a common computer input device a keyboard a user presses a key which transfers information to a computer in computing an input device is a piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer or information appliance examples of input devices include keyboards mouse scanners digital cameras and joysticks audio input devices may be used for purposes including speech recognition many companies are utilizing speech recognition to help assist users to use their devices input devices can be categorized based on modality of input eg mechanical motion audio visual etc whether the input is discrete eg pressing of key or continuous eg a mouses position though digitized into a discrete quantity is fast enough to be considered continuous the number of degrees of freedom involved eg twodimensional traditional mice or threedimensional navigators designed for cad applications keyboard computer keyboard keyboards are a human interface device which is represented as a layout of buttons each button or key can be used to either input a linguistic character to a computer or to call upon a particular function of the computer they act as the main text entry interface for most users traditional keyboards use springbased buttons though newer variations employ virtual keys or even projected keyboards it is typewriter like device composed of a matrix of switchesthere also happens to be another keyboard that is like an input device for musical instrument which helps to produce sound examples of types of keyboards include keyer keyboard lighted program function keyboard lpfk thumb keyboard pointing device a computer not pointing device pointing devices are the most commonly used input devices today a pointing device is any human interface device that allows a user to input spatial data to a computer in the case of mouse and touchpads this is usually achieved by detecting movement across a physical surface analog devices such as 3d mice joysticks or pointing sticks function by reporting their angle of deflection movements of the pointing device are echoed on the screen by movements of the pointer creating a simple intuitive way to navigate a computers graphical user interface gui pointing devices which are input devices used to specify a position in space can further be classified according to whether the input is direct or indirect with direct input the input space coincides with the display space ie pointing is done in the space where visual feedback or the pointer appears touchscreens and light pens involve direct input examples involving indirect input include the mouse and trackball whether the positional information is absolute eg on a touch screen or relative eg with a mouse that can be lifted and repositioned for pointing devices direct input is almost necessarily absolute but indirect input may be either absolute or relative for example digitizing graphics tablets that do not have an embedded screen involve indirect input and sense absolute positions and are often run in an absolute input mode but they may also be set up to simulate a relative input mode like that of a touchpad where the stylus or puck can be lifted and repositioned examples of types of pointing devices include mouse touchpad pointing stick touchscreen trackball highdegree of freedom input devices some devices allow many continuous degrees of freedom as input these can be used as pointing devices but are generally used in ways that dont involve pointing to a location in space such as the control of a camera angle while in 3d applications these kinds of devices are typically used in virtual reality systems caves where input that registers six degrees of freedom is required composite devices wii remote with attached strap input devices such as buttons and joysticks can be combined on a single physical device that could be thought of as a composite device many gaming devices have controllers like this technically mice are composite devices as they both track movement and provide buttons for clicking but composite devices are generally considered to have more than two different forms of input examples of types of composite devices include joystick controller gamepad or joypad paddle game controller jog dialshuttle or knob wii remote video input devices microsoft kinect sensor works by detecting human motion visually video input devices are used to digitize images or video from the outside world into the computer the information can be stored in a multitude of formats depending on the users requirement examples of types of a video input devices include digital camera digital camcorder portable media player webcam microsoft kinect sensor image scanner fingerprint scanner barcode reader 3d scanner laser rangefinder eye gaze tracker computed tomography magnetic resonance imaging positron emission tomography medical ultrasonography audio input devices audio input devices are used to capture sound in some cases an audio output device can be used as an input device in order to capture produced sound audio input devices allow a user to send audio signals to a computer for processing recording or carrying out commands devices such as microphones allow users to speak to the computer in order to record a voice message or navigate softwareaside from recording audio input devices are also used with speech recognition software examples of types of audio input devices include microphones midi keyboard or other digital musical instrument punched paper punched cards and punched tapes were much used in the 20th century a punched hole represented a one its absence represented a zero there were mechanical and optical readers other gesture recognition digital pen magnetic ink character recognition sipandpuffcomputer input device peripheral display device output device n p milner 1988 a review of human performance and preferences with different input devices to computer systems in proceedings of the fourth conference of the british computer society on people and computers iv d m jones and r winder eds cambridge university press new york ny usa 341362 qquotes vtebasic computer componentsinput devices keyboard image scanner microphone pointing device graphics tablet joystick light pen mouse optical pointing stick touchpad touchscreen trackball refreshable braille display sound card webcam softcam video card output devices monitor refreshable braille display printer speakers plotter sound card video card removable data storage optical disc cd dvd bluray disk pack floppy disk memory card usb flash drive computer case central processing unit cpu hdd ssd sshd motherboard network interface controller power supply randomaccess memory ram fax modem expansion card ports ethernet firewire ieee 1394 parallel port serial port ps2 port usb thunderbolt displayport hdmi dvi vga esata audio jack 