Input Devices Theory Notes Task An input device is anything that is used to get data INTO the computer. Write a couple of sentences to describe the following input devices and add your own images. Input device Keyboard
Description A keyboard is used to enter text into the computer. It has a set of alphabet keys, number keys and function keys. Keyboards usually use a QWERTY layout. If you have wrist pain you can get an ‘ergonomic keyboard’
Where used? For computers
Pros Usually it comes with the computer, people need very little training to use keyboard, skilled typist can type really quickly, special keyboards are available
Cons Easy to make typos, time consuming if you are not good at it, can’t create diagrams, bad for disabled, excessive use can lead to health problems
Mouse
You use it to control what goes on in the screen Usually have 2 buttons (LR) and a scrolling wheel. They have different functions.
Computers
Ideal for desktop computers, comes with computer, require little training as most people are familiar, works well with a keyboard
They need a flat space close to the computer, older types have balls that get dirty and needs to be cleaned, excessive use can lead to health problems, wireless mouse needs battery
Touchpad
Usually found on laptops Can be used in place of a mouse due to lack of space Sensors beneath detect fingertips on top, other materials don’t work Some have 2 buttons that replace the 2 on a mouse
Laptops
Useful for laptops when there is no mouse, the pad’s position is fixed, not much finger movements needed
Take practice and skill to use, no gloves will work on it, moist, calloused fingers can disrupt signals
Joystick
Originally used for pilots Now for gamers for a more realistic environment You can move it in many directions and the computer can detect it, it sometimes also has a button or two
Gaming devices, some machines such as cranes, trucks, powered wheelchairs
Better experience for racing/flying games
Some find it more difficult to control, they aren’t that strong, and can break.
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Concept Keyboard
A flat board that has a grid of buttons, you can program them the way you want, an sheet is placed on top so you know what you’re doing Used for fast input
McDonalds, primary school
Faster for making non-text selections, such as on a menu Keyboard is waterproof
Not good for text input (or sometimes numbers) Limited to the options on the keyboard, not as much function as a regular keyboard
Touch screen
Both input and output You view things on the screen, and also click and move on the screen
Cashpoints at banks, info centres, ticket terminals
Easy to use, no extra things like mouse is needed, software can change the screen, so more flexibility than a concept keyboard which has fixed functions
Hard to input loads of data, not very accurate, tiring to use for long time, quite expensive, it is easily damaged
Converts things on paper to digital formats in a computer It works by shining a light which gets reflected and the computer identifies the colour of light Flatbed are more used and better than handheld scanners
School, office, home, digital artist’s workshop
Flatbeds are accurate and produce high-quality images, digitalised images can be included in documents, digitalised images it can be enhanced with graphics software
Images from scanners takes up many memory space, images loses some quality in the scanning process, the quality of the final image is dependant on the quality of the original
Used by graphic designers and illustrators Way more accurate A flat pad and a special pen
Anywhere…
Much more natural feeling, extremely accurate
Not suitable for general selection of work, expensive
Scanner
Graphics tablet
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Microphone
Inputting sound Sound detected by microphone and electrical signal sends to computer Now, some software can allow user to dictate the text in a computer
Concert places, music rooms, recording room, karaoke
Pretty much the only way to record sound
Not as accurate as the real voice
Webcam
Web camera, either built into laptop or connected with USB cable Uses snapshots and frames and moving them to create motion Used in security, chatting, tourists
You can use it to video chat with others through internet, takes images, help security and takes picture when there is movement
Not clear, slow if frames per second are low
Barcode Reader
Automatic input device Scans and reads the barcode using a red light, reflected light is interpreted by the computer and checks about the product
Since prices are stored in database not barcodes, whenever there is a price change you only need to change the database
Might fail at some time, easy to break
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Optical Mark Reader
Used in multiple-choice test where you colour in an area. Less light is reflected where there is a pencil mark and the pattern of marks is sent to a computer for interpretation.
Fast method for inputting tons of data, only 1 computer needed, very accurate
Might misinterpret if mark not clear enough, not suitable for text input, only reading marks, you must have a specially prepared form to mark answers on.
Optical Character Recognition
A scanner and software Scans the text on a paper, then computer changes text into editable type
Reads post addresses at post office, it is cheaper than hiring someone to input text, faster as well, latest software can recreate tables and layout
Depends on how clear the writing is. Not 100% accurate, not worth for small amounts of text.
Magnetic stripe reader
Usually on back of credit cards, membership cards‌ Holds personal data, up to 60 characters Card is swiped into a MSR, and data fed into computer
Simple and easy, cards are inexpensive, data on cards can be altered, security is better with PIN numbers
Limited storage space, data can be destroyed by magnetic force, thieves can obtain readers and read data
Remote controls
Handheld device to control a machine a short distance away
It’s simple, portable, don’t need to walk over to do something
Can be blocked by obstacles
Biometric Devices
Reads fingerprints, has retinal recognition, even facial
Very secure
System might fail and hard to fix
Sensors (various types) what types are there?
Sensors are used to detect physical quantities outside a computer such as light, temperature and pressure. Collect data automatically 'Analogue to Digital Converter' (ADC) must be connected between the computer and the sensor. This device converts the analogue signals from the sensors to digital data that the computer can process.
Can automatically collect accurate data
Might break easily
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