Input Devices
KEYBOARD
The keyboard is a manual input device, used for inputting text and commands to the computer. It has QWERTY- layout.
Uses
Keyboards are used to input data into application software.
To input numbers into spreadsheets.
Also used to type commands to the computer (eg. Ctrl+P, Alt+F4, etc).
Advantages
Enables fast entry of new text into a document.
Well tried technology and well-known method of data entry.
Ideal for applications like word processors, composing emails where you have to create original text.
Easy to do verification check as data is entered, as it appears on the screen simultaneously.
Disadvantages
Users with limited arm/wrist use can find keyboards hard to use.
Entering data is slow when compared to direct data entry (e.g. Optical mark recognition).
They use up desk space as they are quite large.
MOUSE
A mouse is a pointing device used for making selections and giving instructions to the computer. The left button is for making selection by double-clicking o it and the right button is to bring drop-down menus. There is a scroll button which speeds up the process of moving through the document.
Uses
Make selections in a Graphical User Interface (GUI).
Move the pointer onto a button, icon, hyperlink etc.
Activate context/pup-up menu (on right click).
Scroll quickly through long documents.
Advantages
Easier to select and move items than the keyboard.
Enables rapid navigation through long documents/web browsers.
Occupies smaller area on the desktop.
Disadvantages
Difficult to use for people who have limited wrist/finger movement.
Needs a flat surface to operate, so cannot be used on the move
CONCEPT KEYBOARD
Concept keyboard uses icons or phrases instead of standard letters. A single key represents an item on the keyboard.
Uses
Used in fast food restaurants, offices and shops.
Advantages
Enables fast data entry - There is no need to type in the whole command.
Waterproof - useful in a restaurant environment.
Tamperproof - preventing people from keying in information which could corrupt the system.
NUMERIC KEYPADS
A numeric keypad is a keyboard with only numbers.
Uses
Used in Automatic Teller Machines (ATMs), where customers can key in their personal identification number (PIN), or an amount of money.
Used to key in phone numbers into telephones.
Electronic Point Of Sale (EPOS) Terminals has numeric keypads in case the barcode reader fails.
Used in Chip and PIN devices to key in the PIN, or amount of money.
Used to enable fast entry of numeric data into a spreadsheet.
Advantages
Numeric keypads are faster than standard keyboards for entry of numeric data.
Since many are small devices (e.g. mobile phones), they are easy to carry around.
Disadvantages
Can be difficult to use due to the very small keys.
Difficult to use for entering text.
Sometimes the order of the numbers isn’t very intuitive.
TOUCHPAD
The touchpad is a pointing device used in laptops to control the pointer by moving fingers on the touchpad.
Uses
Used for opening, closing and minimising programs.
Used for grouping, moving and deleting files
Useful when editing images (e.g. controlling the size and position of the image)
Used for controlling the position of a pointer on the screen to select menu items.
Used for selecting an icon.
Advantages
Does not need a flat surface to operate, so can be used while travelling.
Built-in on laptops, so no need to carry an extra device.
Disadvantages
Difficult to use for people who have limited wrist or finger movement
Hard to use for actions like – drag and drop
Long term use can lead to health problems like RSI
TRACKER BALL
Trackerball is a pointing device similar to a mouse except that it has a ball on the top of the device. Users can control the pointer on the screen by rotating the ball.
Uses
Used in a similar way as that of a mouse
Usually used by people with poor motor skills such as very young people with disabilities
Advantages
Easier to use than a mouse if the user has wrist or finger problems
Allow faster navigation than a mouse
Requires less space than a mouse as the device remains stationary and only the ball over it moves
Disadvantages
Not a part of default peripherals like mouse, keyboard and needs to be purchased separately.
Takes time for the user to get used to the device.
JOYSTICK
The joystick is a pointing device used for selecting objects on the screen.
Uses
Playing Computer games
Operating Car-driving, flight simulators, automatic wheel-chairs.
Selecting items, menu options similar to a mouse.
Advantages
Ideal for quick movements – games, simulators.
Easy to use for disabled people as joysticks can be operated by foot or mouth.
Disadvantages
Text selection-entry is very slow compared to keyboard, mouse.
Expensive than a mouse, keyboard.
Generally not part of the default peripheral (keyboard, mouse) and needs to be purchased separately.
TOUCHSCREEN
Uses
Information Kiosks
Tablet computers
Laptops
Smartphones
Supermarkets EPOS
ATMs
Restaurants
Airport - self-check-in
Advantages
Simple to use without any training required.
Ideal where space is limited like Smartphone, tablet etc.
Tamper-proof so other data cannot be entered that could corrupt the system
Allows faster selection than a keyboard or mouse.
Disadvantages
Screen gets dirty making items on-screen hard to see.
The danger of spreading germs with many people touching the same screen.
Expensive than a keyboard and mouse.
REMOTE CONTROL
Uses
Operate home appliances – TV, DVD players, satellite receivers, music systems, Air conditioners etc.
Used to operate multimedia projectors, industrial and domestic robots.
Advantages
Can operate a device wirelessly.
Ideal for people with disabilities to operate devices at a distance.
Can control devices safely from a distance (eg: robot used to investigate a bomb).
Disadvantages
Uses infra-red signals which may be blocked by objects in the path thus making remote control not to operate.
Needs batteries to operate that need regular replacement.
Small buttons can be pressed by mistake that could alter the device settings
SCANNER
Uses
To convert hard copy documents to digital format (Soft copy).
Used for scanning text into word-processing or other packages using built-in OCR (Optical Character Recognition).
Advantages
Faster data entry than keyboard if used for scanning text with OCR software.
Can be used to digitise old documents such as maps, pictures, photographs for archive purposes.
Can be used with image editors to repair, improve old photographs.
Disadvantages
Takes up a lot of space.
Takes a long time to scan long documents like books.
Quality of scanned items depends on scanner resolution.
Text scanned using OCR may contain errors.
GRAPHICS TABLET
A graphic tablet is a flat sensitive surface on which we can draw using a special pen and the drawing will appear on the monitor for saving in the computer. it is mainly used for free-hand drawing.
Uses
Used for retouching photographs.
Inputting freehand drawings.
Used for specialist applications such as designing a kitchen using Computer-Aided Design (CAD)
Advantages
Accurate freehand drawing than using a mouse.
Used in countries like Japan, China where graphical characters are used instead of letters and words.
Disadvantages
Takes up a lot of space.
Specialist tablets are Expensive
DIGITAL CAMERA
Advantages
No film to develop, so quicker to produce a photo.
Images can be previewed and deleted immediately.
Images are stored in the form that can be placed in documents, presentations, websites etc.
Many cameras are now equipped with Bluetooth, Wi-Fi enabling them to send directly via internet.
Disadvantages
Quality of photos may not be as high quality as those produced using films (limited by camera resolution).
Photographer needs to have computer skills to use digital photographs properly.
VIDEO CAMERA
Advantages
Can capture both still and moving images.
Easy to transfer video to the computer.
Can preview the video.
Allows using built-in filters.
Disadvantages
Can erode privacy as CCTV camera are present in many public places.
It is difficult to produce good video without training.
Expensive to buy.
WEBCAM
Uses
Simple Video-conferencing.
Record video for inclusion in websites.
Taking quick photos in emigration counters in airports, identifications (ID) cards etc.
Advantages
Can see reactions of people as you are talking to them.
Compact in size.
Disadvantages
Image/video quality is poorer than Digital/Video camera.
Usually operates in fixed positions.
MICROPHONE
Uses
Hands-free operation (eg. In a car).
Can be used to dictate text rather than typing (Voice recognition).
Video conferencing.
Add narrations in presentations, videos.
Input speech for VoIP – Voice over Internet Protocol, an inexpensive way of conducting phone calls using internet.
Advantages
Can be used by disabled people to input data/instructions.
Can improve safety for car phones.
Inexpensive.
Disadvantages
Background noises can cause problems for voice recognition systems.
Voice recognition systems are inaccurate
Sound files, when stored, take up a lot disk space.
SENSORS
Sensors are input devices used to measure physical quantities such as temperature, pressure, humidity, amount of light, etc. The analogue signals picked up by sensors can be sent to and then analysed by the computer.
Since the computer is a digital device, the analogue signals from sensors have to be converted into digital using ADC – Analogue to digital converter.
Advantages
Accurate readings than those taken by humans.
Readings can be taken more frequently than humans.
They can work even when a human is not present, so cost is less.
They can work in dangerous environments (eg: down deep mines or in nuclear reactions etc.).
Disadvantages
Purchase cost.
Dirt and grease may affect performance.
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