input output Flashcards
What are ‘input devices’?
Hardware devices that allow data to be entered into a computer
What are the two types of input devices?
Manual input devices
Direct input devices
Manual input devices
Data is input into the computer by hand (people have to do most of the work).
Keyboard
Text, numbers and instructions
Used to input data into applications
Used to enter commands into the computer.
Numeric keypads
Used to enter numbers into a computer system
- Used in: ATMs, telephones, chip and pin devices
Joysticks
Similar functions to mice and trackballs. has buttons
Can control characters or objects in video games
Can control industrial machinery
Used in simulators.
wheelchair
Pointing devices uses
Used to control a cursor on a screen.
Opening, closing, maximising and minimising programs and files Moving, grouping and deleting files Using applications Touchpad: Mice: Tracker ball:
Touch screens
Input commands into a computer by pressing or touching buttons / icons on the screen removes the need to use a mouse.
2 types of touch screen
Resistive
capacitive
Resistive touch screen
Sensitive to pressure (can use glove)
Capacitive touch screen
Sensitive to static electricity (no glove)
Keyboard advantages
Fast entry of new text into a document.
Well-known method.
Easy to use for most people.
Easier to do verification checks as data is entered (can immediately compare the source document with typed data on the screen).
Keyboard disadvantages
It can be difficult to use if the user has limited arm/wrist use.
Slow method when compared to direct data entry.
It is a fairly large device that uses up valuable desk space.
numeric keypad advantage
adv
Faster than standard keyboards when entering numeric data.
Because many are small devices, they are very easy to carry around.
mouse advantage
It is a faster method for choosing an option than a keyboard.
It’s a very quick way of navigating through applications and the internet.
Does not need a large desk area when compared to a keyboard.
numeric keypad disadvantage
dis
Sometimes, they have small keys, which can make input more difficult.
Sometimes, the order of the numbers on the keypad is not intuitive.
mouse disadvantage
It can be more difficult for people with restricted hand/wrist movement than using a keyboard for data entry.
Easy to damage, the older type of mouse quickly becomes clogged up with dirt.
Difficult to use if no flat surface is readily available.
tracker ball advantage
Does not need the same fine control as a mouse.
It is easier to use than a mouse if the operator has problems with their wrist.
More accurately position the pointer on the screen.
Needs less desk space than a mouse or keyboard.
trackerball disadvantage
It is not supplied with the computer as a standard; therefore, it is more costly.
Users may need training because it is not standard equipment.
remote control advantage
It can be operated from any reasonable distance.
In some conditions, e.g., in chemically hazardous environments, we can control and measure from safe distances.
remote control disadvantage
Difficult to use for people with limited hand/wrist movements.
Physical obstacles can easily block the signal.
remote control uses
Uses:
Televisions, satellite systems, DVD/Blu-ray players and Hi-Fi systems, to alter controls such as volume, on/off, etc. Used to control multimedia systems. Used in industrial applications to remotely control processes.
joystick use
game
aircraft control
wheelchair
disadvantage
more difficult to control fine movement of pointer on screen than mouse
driving wheel advantage
(in racing game )
control movement more accurately than mouse or joystick
force feedback can be added to simulate road
driving wheel disadvantage
only one purpose
more elements is expensive such as force feedback and gears
touch screen advantage
intutive
space saving input and oupt is same device
cost effective for shop cause self service
faster entry than keyboard or mouse
touch screen disadvantage
not suitable for large ammount of data
not very accurate for selecting small areas
dirty screen
scanner use
Scanning documents and converting them into different formats
Scanning in old documents to protect them in case the original is lost/damaged.
Scanning in photographs for storage
Scanning in barcodes at POS terminals.
convert stuff to digital data
scanner advantage
Images can be stored for editing at a later date.
It is possible to recover damaged documents by scanning and producing an acceptable copy.
Digitalized stuff can be used on electronic documents
store documents digitaly
scanner disadvantagee
can take up lots of storage
can be reduction in quality
slow input method
Digital camera advantage
Easier to produce better-quality photographs than with a traditional camera.
Uploading photographs to a computer is faster than scanning hard copies.
Memory cards can store many thousands of photographs.
There is no need to develop film and printouts; it saves money and is more environmentally friendly.
Unwanted images can quickly be deleted from a memory card.
Videos are moving
record audio too
more realistic record
Digital camera disadvantage
Memory might be full
memory card can get corrupted
battery might run out
video file can be large
might need expensive software to edit
Microphone advantage
Faster than typing
used by disabled people
Microphone disadvantage
cheap one is low quality
sound file big
more error prone than typing
Sensor
Detects and responds to input from environment
eg light, temp,motion,pressure
Sensor advantage
More reliable than human because human may forget
Readings more accurate
Can be used in dangerous places where humans cant go
dont need human
24/7 as humans will get tired etc
Actions or warnings will happen immediately
Sensor disadvantage
Digital sensor need constant power source (passive sensor is fine)
If it malfunctions in a remote place user will not know
bad data if faulty
most need analogue to digital
Light pen/stylus advantage
Easy to use
give accurate positioning (more accurate than touch screen)
Ergonomically designed
dont take up much space (portable)
lightweight
no moving parts
Stylus/lightpen disadvantage
light pen only used with some screens (also old) CRT
Graphics tablets are expensive
can block view of computer screen
not good for basic operations such as printing clicking etc
Magnetic strip reader (black line on card)
ADVANTAGE
faster than manual
error free
inexpensive
simple to use
Magnetic strip reader (black line on card)
DISADVANTAGE
small storage
data can be destroyed by magnetic field
insecure
need reader ( no online)
if damaged bad
doesn’t work at distance
CHIP AND PIN READER ADV/DIS (magnetic strip but better)
advantage
more secure
hold more info ( now has chip)
wireless
disadvantage
people can see ur pin
u can forget pin
RFID what does it stand for????!!!??!?!
RFID reader
RFID tag
radio frequency identification
reader for reading data/scan
tag for storing data
3 elements of RFID and use/how it work
scanning antennae
decoder
rfid tag
provides unique identifier for things
library
reader send signal then tag respond
active have own battery
passive need reader battery
RFID ADVANTAGE
no line of sight needed ( dont need to be precise)
work within few meters
fast
track things
u can change the data
RFID DISADVANTAGE
easy to hack
can be affected by other electrical devices
limited range to 3m
more expensive than barcode
OMR (optical mark recognition) adv
adv
fast to input
more accurate
OCR (optical character recognition) adv/dis
fast
avoid typing errors with manual
cheaper than employing if accuracy isnt issue
not very reliable (some handwriting hard to read etc)
if want accurate need people to check which cost money and time
BARCODE uses
country of origin number
Manufacture number
item number
check digit
NO PRICE
advantage and disadvantage of barcode
faster than manual
automatic stock control
reliable
inexpensive
more easily damaged
QR code adv
more info than barcode
can encrypt
less error than manual
camera can read
QR disadvantage
need smartphone app
new so people dont know
types of monitors
LCD liquic crystals
TFT liquid crystals with film
LED light emiting diodes
multimedia projector adv/dis
Bigger screen so people dont have to crowd around laptop
can be fuzzy
expensive
set up can be complicated
how does laser printer work
uses a laser to draw on a drum to make those parts positively charged
toner is sprayed on and is attracted to the charged areas
drum is pressed against paper
paper is heated by fusser to bind toner
1 drum for each color (4 in total)
laser printer advantage/dis
cheaper for printing often
faster if many is needed
toner is toxic
more expensive initially
how does inkjet printer work
the print head scans and squirts ink at the right places
it squirts ink out of different nozzles (for different coloured ink)
Nozzles are on the print head
stepper moves paper forward
inkjet printer adv/dis
higher quality than laser
printer is cheap
cheaper if used less
slow output if many is needed
expensive for ink
can smudge / ink is not waterproof
how it works dot matrix printer
pins press a inked ribbon against the paper
when the pin pressed it leaves a dot
dot matrix printer adv/dis
cheap
durable
can be used in dirty environments
can be used on continous sheet
loud
slow
poor quality
no color
what is plotter
advantage and disadvantage
what it is
for architectural drawings
uses markers to draw on a paper moves marker up down left right
advantage
high quality
accurate
many materials can be printed on
disavantage
expensive
giant
slow
3d printer adv/dis
puts layer of plastic/resin to print an object
manufacturing objects
cheaper than conventional way
expensive initially
Speaker adv/dis
Amplified sounds are loud
simple techonology
disturbing to people
take up space
sound quality is only good in expensive speakers
Actuator definition
A device that controls a mechanism responds to a control signal and produces a mechanical action
often works with sensors
eg motor pump header
Actuator adv/dis
allow remote operation
inexpensive
addition device that can go wrong
need to be converted to digital
OMR (optical mark recognition) dis
will not read accurately unless lined up properly and shaded properly
dirty marks can be misinterpreted as data
can only read
form must be designed well
