what are computer input devices

8/3/2019 What Are Computer Input Devices

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What are Computer Input Devices?

Computer input devices are hardware components that help you transfer information,data, etc. to the computer. Without the computer input devices, you computer will be

more or less like a television set. These devices help you send data into the computer or

even help you retrieve the data into a hard copy. So an input device is any peripheraldevice that helps provide data and control signals of a computer. The input devices can be

classified into the following categories:

Modality of input like audio, video and mechanical devices.

A continuous input device like the mouse whose position is fast enough to beconsidered as continuous.

The freedom provided to the user while using the device like a 2 dimensional

mouse or 3 dimensional navigator (especially for CAD applications).

Many computer input devices also, are classified according to their pointing ability.

These pointing devices are classified as:

Direct input where the pointing is done directly in space where the cursor is seen.

For example, touchscreen pointers and light pens.

Indirect pointers in case of a trackball or mouse. Pointers for touchscreen where the positional information are absolute or relative

where the mouse is lifted and positioned according to need.

Computer Input Devices List

Let us now have a look at the various computer input devices list. These input devices

help in manipulating various information on the computer. The following are some of themost commonly used input devices.

Keyboard: The oldest and most widely used computer input device is the keyboard. It is

available with the desktop computers, laptops, etc. The computer keyboard contains allthe alphabetical and numerical keys for input of data and commands. The keyboard is

generally connected to the computer with a wire but nowadays wireless keyboards are

also very common.

Mouse: The small hand-held computer device that helps make selection and navigation

of the screen easy is the mouse. The computer mouse displays a cursor on the screen that

serves as a guide for opening files and folders, and making selections. The mouse, likethe keyboard, is either connected with the computer through a wire or has a wireless

connection.

Graphics Tablets: The graphic tablet uses a pen-like computer input device that is called

a stylus. This helps one write on tablets or touchscreens like a pen. Some tablets and

stylus have buttons, that help the user use it like a mouse. Many latest tablet models,allow the user to use their fingers instead of a stylus.


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Joysticks: If you are an ardent fan of gaming and love to play many advanced games,

then you may be aware of a joystick. This is a movable stick with a button or two thathelps one control the movements of characters in the game. Many latest joystick models

come with different buttons to help you make complex movements with just a push with

your fingers.

Scanners: Scanners are computer input devices that help you make virtual photocopies

of your hard copy document or even a photograph. You can copy a digital image of thedocument you wish to copy and save it on the computer or take prints. This copy can be

edited by running a graphics program.

Headsets: The headsets are computer input devices that have an earphone as well as amicrophone. This helps you record your voice, dictate data or even commands to the

computer. Some headsets help you keep your hands free for working on different tasks.

You can even add voice recognition software, so that only your voice will be accepted by

the computer to dictate commands.

Computer Input Devices Examples

There are different devices that help you share information with your computer in

different formats. The following are a few computer input devices examples that help you

digitize images and videos from other devices into your computer.

Computer Input Device Examples for Video Formats

Web cam

Image scanner Digital camera

Barcode reader

Fingerprint scanner

3D scanner

Laser rangefinder

Video capture hardware

MIDI Keyboard

Computer Input Device Examples for Medical Imaging

Magnetic Resonance Imaging (MRI)

Computerized Tomography (CAT Scan)

Positron emission tomography

Ultrasonography

These are some of the computer input devices that help you store data from other devices

into your computer. Technology continues to come up with more advanced modes oftransfer of information and data. The computer input devises listed in this article are


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some of the commonly used devices today. I hope this article has helped you learn and

understand what are computer input devices.

What is a Computer Output Device?

In the world of computers, input/output (I/O) refers to the communication between a

computer and the user. Input is the data sent to the system, whereas output is the data sentby the system to the outside world. Computer output devices are computer hardware

equipment, that are used to communicate the results of data processing carried out by a

computer to the user. There are a number of devices, which produce data in different

forms, which includes audio, video or hard copy. Output device of computer are types ofperipheral hardware connected, that is connected to the computer, either using cables or

over a wireless network. Immaterial whether you have desktop computers, laptop

computers, supercomputers, etc., you will require at least one computer output device.

Which Devices are Computer Output Devices?

An output given by the computer can be in the form of a display on the screen or a

printed document or a song, that is played. Most of the computer output devices are

common to home as well as office environment. At the same time, there are some

devices, which are not as commonly available. Having said that, let's take a look atcomputer output devices list.

Monitor

A monitor is also called video display terminal (VDT). The visual display of the

processed data, which the users can view is got through the monitor. Computer monitors

come in a variety of screen sizes and not to forget visual resolutions. There are two typesof computer monitors available, namely CRT and flat panel. All monitors rely in a video

card, which is located on the motherboard to display the information. It is the video card,

which processes the data into images, which is eventually displayed on the monitor.

Printer

The next of the computer output devices is the printer, which is an external hardware

device, which takes processed data from the computer to generate a hard copy of the data.After the monitors, printers are the most used peripherals on computers and they are

commonly used to print text data, images, etc. There are three main types of computer

printers, namely ink jet, laser printers and dot matrix. Each of these printer type uses adifferent technology to print the data.

Speaker

A speaker is a hardware device, that is connected to a computer's sound card, which

outputs sound generated by the card. Audio data generated by the computer is sent to the

audio card, that is located in the expansion slot. The card translates the data into audio

signals, which are then sent to either the speakers or headphones. In the initial phase,
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computers had on-board speakers, which generated series of different tones and beeps.

When the popularity of multimedia and computer games grew, higher quality computer

speakers came into the market. These new speakers were known for higher quality soundeffects and music.

ProjectorIt is a hardware device, with which an image like a computer screen is projected onto a

flat screen. Image data is sent to the video card, by the computer which is then translated

into a video image and sent to the projector. A projector is often used in meetings or tomake presentations, because they allow for a large image to be shown, with which the

display is available for a large audience.

Plotter

Plotters, like printers, create a hard copy rendition of a digitally rendered design. The

design is sent to a plotter through a graphics card and the image is created using a pen. In

simple words, plotters basically draw an image using a series of straight lines. This

computer output device is used with engineering applications.

Discs

There are different types of discs, such as CD, DVD and floppy discs, which are output

devices, that are also used to store data, hence they are also input devices at the same

time. The data is sent to the disc and the data is embedded on the disc, which is retrieved,

when required.

This is computer output devices information in short. All computers might not have all

the computer output devices, but it certainly does have one of the visual output device,namely either a monitor or projector.

Input devices:

Webcam

Typical low-cost webcam used with many personal computers
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Animated set of x-ray images of a webcam. Images acquired using an industrial

computed tomograph.

A webcam is a video camerathat feeds its images in real time to a computerorcomputer

network, often via USB, ethernet, orWi-Fi.

Their most popular use is the establishment ofvideo links, permitting computers to act asvideophones orvideoconference stations. This common use as a video camera for the

World Wide Webgave the webcam its name. Other popular uses include security

surveillance and computer vision and there are also uses on sites like video broadcastingservices and for recording social videos .

Webcams are known for their lowmanufacturing cost and flexibility,[1] making them the

lowest cost form ofvideotelephony. They have also become a source of security and

privacy issues, as some built-in webcams can be remotely activated viaspyware.

Digital camera

A digital camera (ordigicam) is a camera that takesvideoor stillphotographs, or both,

digitally by recording images via an electronicimage sensor. It is the main device used inthe field ofdigital photography. Most 21st century cameras are digital.[1]
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Digital cameras can do things film cameras cannot: displaying images on a screen

immediately after they are recorded, storing thousands of images on a single small

memory device, and deleting images to free storage space. The majority, including mostcompact cameras, can record moving video with sound as well as stillphotographs. Some

can crop andstitch pictures and perform other elementary image editing. Some have a

GPS receiver built in, and can produceGeotagged photographs.

The optical system works the same as infilm cameras, typically using a lens with avariable diaphragm to focus light onto an image pickup device. The diaphragm and

shutter admit the correct amount of light to the imager, just as with film but the image

pickup device is electronic rather than chemical. Most digicams, apart from cameraphones and a few specialized types, have a standard tripod screw.

Digital cameras are incorporated into many devices ranging from PDAs and mobile

phones (called camera phones) to vehicles. TheHubble Space Telescopeand other

astronomical devices are essentially specialized digital cameras.

Barcode reader

A handheld barcode scanner

A barcode reader (orbarcode scanner) is an electronic device for reading printed

barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensortranslating optical impulses into electrical ones. Additionally, nearly all barcode readers

contain decodercircuitry analyzing the barcode's image data provided by the sensor and

sending the barcode's content to the scanner's output port.

Laser rangefinder
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A long range laser rangefinder is capable of measuring distance up to 20 km; mounted ona tripod with an angular mount. The resulting system also provides azimuth and elevation

measurements.

A laser rangefinder is a device which uses a laserbeam to determine thedistance to anobject. The most common form of laser rangefinder operates on the time of flight

principle by sending a laser pulse in a narrow beam towards the object and measuring the

time taken by the pulse to be reflected off the target and returned to the sender. Due to the

high speed of light, this technique is not appropriate for high precision sub-millimetermeasurements, where triangulationand other techniques are often used.

MIDI keyboard

A close up of one style of MIDI keyboard based on the piano user interface

A MIDI keyboard is typically apiano-style user interface keyboard device used for

sending(MIDI) signals or commands over a USB or MIDI cable to other devices

connected and operating on the same MIDI protocol interface. This could also be a
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personal computer running software such as a digital audio workstation (DAW) that

listens to and sends MIDI information to other MIDI devices connected by cable or

running internal to the personal computer system. The basic MIDI keyboard does notproduce sound. Instead, MIDI information is sent to an electronic module capable of

reproducing an array of digital sounds or samples that resemble traditional analog

musical instruments. These samples or waveforms are also referred to as voices ortimbres.

Not all MIDI keyboards are based on the piano style user interface. Many MIDI keyboard

controllers have pads or buttons that also send MIDI signals, and most pads have a

velocity sensing capability so that varying volumes of sound can be played/voiced.Another such keyboard device is the Continuum Fingerboard which is based on a

"fretless" type keyboard interface enabling portamento style note changes at will during

play.

An illustration of the Continuum Fingerboard.

Another MIDI keyboard implementation is the Tonal Plexus keyboard that provides for

up to 1266 different tonal pitches possible in the TPX6 1266 Keys (Microtonal MIDI

Controller). There are numerous other MIDI controllers that are also not based on thepiano style user interface, but on newer interfaces with broader application possible

because of computer technology.

In the MIDI protocol used in each of these midi controllers, an encoding scheme is used

to map a MIDI value to a specific instrument sample. Also, other sound parameters suchas note volume (velocity), aftertouch, pitch bend and modulation controls are also

included in the MIDI protocol scheme. The keyboard merely acts as a MIDI controller of

sound modules and other MIDI devices, including activating sounds by MIDI controlwithin DAWsoftware.

MIDI keyboards are a very common feature of a recording studio, and any DAW setup.

Most include a transpose function and the ability to set different octaves. Many MIDI

keyboards havepitch bendandmodulationwheels. Some also have extra sets of

assignable rotary knobs and/or buttons for sending custom MIDI messages to thesynthesiser, sampler or DAW software. Devices with extra features (also including

rhythm input, instrument selection, transport control) are sometimes called keyboard

controllers.

Other features that some MIDI keyboards might include are:

Input for foot switch (usually used as a sustain pedal)
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Input for a foot expression controller

Semi-weighted or fully weighted keys

Capability of sending aftertouch

Direct USB connection for use with computers

MIDI keyboards come in a range of sizes, from 25 keys (two octaves) to full 88-keylength. MIDI keyboards with fewer than 61 keys tend not to have weighted keys.

Magnetic resonance imaging

Magnetic resonance imagingIntervention

Sagittal MR image of the knee

ICD-10-PCS B?3?ZZZ

ICD-9: 88.91-88.97

MeSH D008279

OPS-301 code: 3-80...3-84
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Para-sagittal MRI of the head, with aliasing artifacts (nose and forehead appear at the

back of the head)

Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI),ormagnetic resonance tomography (MRT) is a medical imagingtechnique used in

radiology to visualize detailed internal structures. MRI makes use of the property ofnuclear magnetic resonance(NMR) to image nuclei of atoms inside the body.

An MRI machine uses a powerful magneticfield to align the magnetizationof someatoms in the body, and radio frequency fields to systematically alter the alignment of this

magnetization. This causes the nuclei to produce a rotating magnetic field detectable by

the scannerand this information is recorded to construct an image of the scanned area

of the body.[1]:36 Strong magnetic field gradients cause nuclei at different locations torotate at different speeds. 3-D spatial information can be obtained by providing gradients

in each direction.

MRI provides good contrast between the different soft tissues of the body, which makesit especially useful in imaging thebrain, muscles, the heart, andcancers compared with

othermedical imaging techniques such as computed tomography (CT) orX-rays. Unlike

CT scans or traditional X-rays, MRI does not use ionizing radiation.

X-ray computed tomography

A patient is receiving a CT scan forcancer. Outside ofthe scanning room is an imaging computer that

reveals a 3D image of the body's interior.

ICD-10-PCS B?2

ICD-9-CM 88.38

MeSH D014057

OPS-301 code: 3-20...3-26
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X-ray computed tomography orComputer tomography (CT), is a medical imaging

method employing tomographycreated by computer processing.[1]Digital geometry

processingis used to generate athree-dimensionalimage of the inside of an object from alarge series of two-dimensional X-ray images taken around a single axis of rotation.[2]

CT produces a volume of data that can be manipulated, through a process known as"windowing", in order to demonstrate various bodily structures based on their ability to

block the X-ray beam. Although historically the images generated were in the axial ortransverse plane, perpendicular to the long axis of the body, modern scanners allow this

volume of data to be reformatted in various planes or even as volumetric (3D)

representations of structures. Although most common in medicine, CT is also used inother fields, such as nondestructive materials testing. Another example is archaeological

uses such as imaging the contents of sarcophagi.

Usage of CT has increased dramatically over the last two decades in many countries.[3]

An estimated 72 million scans were performed in the United States in 2007.[4] It is

estimated that 0.4% of current cancers in the United States are due to CTs performed inthe past and that this may increase to as high as 1.5-2% with 2007 rates of CT usage; [5]

however, this estimate is disputed.[6]

Positron emission tomography

ICD-10-PCS C?3

ICD-9-CM 92.0-92.1

MeSH D049268OPS-301 code: 3-74

Image of a typical positron emission tomography (PET) facility
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PET/CT-System with 16-slice CT; the ceiling mounted device is an injection pump forCT contrast agent

Positron emission tomography (PET) [1] isnuclear medicineimaging technique that

produces a three-dimensional image or picture of functional processes in the body. The

system detects pairs ofgamma raysemitted indirectly by apositron-emitting radionuclide(tracer), which is introduced into the body on a biologically active molecule. Three-

dimensional images of tracer concentration within the body are then constructed by

computer analysis. In modern scanners, three dimensional imaging is often accomplishedwith the aid of a CT X-ray scan performed on the patient during the same session, in the

same machine.

If the biologically active molecule chosen for PET is FDG, an analogue ofglucose, the

concentrations of tracer imaged then give tissue metabolic activity, in terms of regionalglucose uptake. Use of this tracer to explore the possibility of cancer metastasis (i.e.,

spreading to other sites) results in the most common type of PET scan in standard

medical care (90% of current scans). However, on a minority basis, many otherradiotracers are used in PET to image the tissue concentration of many other types of

molecules of interest.

Medical ultrasonography

Diagnostic sonography (ultrasonography) is an ultrasound-based diagnostic imaging

technique used for visualizing subcutaneous body structures including tendons,muscles,

joints, vessels and internal organs for possible pathology orlesions.Obstetric sonography

is commonly used duringpregnancy and is widely recognized by the public.

In physics, the term "ultrasound" applies to allsound waves with a frequency above the

audible range of human hearing, about 20 kHz. The frequencies used in diagnostic

ultrasound are typically between 2 and 18 MHz.
http://en.wikipedia.org/wiki/Positron_emission_tomography#cite_note-0http://en.wikipedia.org/wiki/Nuclear_medicinehttp://en.wikipedia.org/wiki/Nuclear_medicinehttp://en.wikipedia.org/wiki/Medical_imaginghttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Positronhttp://en.wikipedia.org/wiki/Positronhttp://en.wikipedia.org/wiki/Radionuclidehttp://en.wikipedia.org/wiki/Computed_tomographyhttp://en.wikipedia.org/wiki/Fludeoxyglucose_(18F)http://en.wikipedia.org/wiki/Fludeoxyglucose_(18F)http://en.wikipedia.org/wiki/Glucosehttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/Medical_imaginghttp://en.wikipedia.org/wiki/Tendonshttp://en.wikipedia.org/wiki/Tendonshttp://en.wikipedia.org/wiki/Muscleshttp://en.wikipedia.org/wiki/Lesionhttp://en.wikipedia.org/wiki/Lesionhttp://en.wikipedia.org/wiki/Obstetric_ultrasonographyhttp://en.wikipedia.org/wiki/Pregnancyhttp://en.wikipedia.org/wiki/Soundhttp://en.wikipedia.org/wiki/Soundhttp://en.wikipedia.org/wiki/File:16slicePETCT.jpghttp://en.wikipedia.org/wiki/File:16slicePETCT.jpghttp://en.wikipedia.org/wiki/Positron_emission_tomography#cite_note-0http://en.wikipedia.org/wiki/Nuclear_medicinehttp://en.wikipedia.org/wiki/Medical_imaginghttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Positronhttp://en.wikipedia.org/wiki/Radionuclidehttp://en.wikipedia.org/wiki/Computed_tomographyhttp://en.wikipedia.org/wiki/Fludeoxyglucose_(18F)http://en.wikipedia.org/wiki/Glucosehttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/Medical_imaginghttp://en.wikipedia.org/wiki/Tendonshttp://en.wikipedia.org/wiki/Muscleshttp://en.wikipedia.org/wiki/Lesionhttp://en.wikipedia.org/wiki/Obstetric_ultrasonographyhttp://en.wikipedia.org/wiki/Pregnancyhttp://en.wikipedia.org/wiki/Sound


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what are computer input devices

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