1.1.3 Input and Output Devices

Question 1

Manual Input Devices

Answer 1

Input devices that require greater human intervention

Question 2

Barcodes

Answer 2

Tend to be used for products
UPC-A
Universal Product Code version ‘A’ retail/warehousing
Code 128 transport/shipping

Question 3

QR codes

Answer 3

Tend to be used for website links etc

Patterns of squares to link a website/information

Question 4

Sensors

Answer 4

Allow for data to be obtained directly without user input. Take measurements of physical properties from real world surroundings

Question 5

Analogue measurements

Answer 5

Data has no constant value - the data changes smoothly rather than in exact jumps

Question 6

Examples of sensors

Answer 6

light, temperature, pressure, humidity

Question 7

Monitoring vs control

Answer 7

Monitoring sees the sensor taking a measurement and reporting a value but not making a change. Control changes it

Question 8

ADC

Answer 8

Analogue to digital convertor - puts signals in a format that a computer can understand (binary)

Question 9

DAC

Answer 9

Digital to analogue convertor - means people can understand it

Question 10

Output devices

Answer 10

Take data produced by a computer and turn it into human-readable form

Question 11

Ink-jet printer

Answer 11

The circuit sends data to tell the printer what jets of ink to heat up and burst the bubbles to each part of the paper
Often used for photographs

Question 12

Ink-jet advantages and disadvantages

Answer 12

+You can combine colours, high quality
+ cheaper than laser
-if you have a shared cartridge, one colour running out means the whole cartridge needs replacing

Question 13

Laser printer

Answer 13

Instructions are sent where a drone rolls beside a roller with toner attracting paper onto the roller as paper comes past to roll the toner onto it
E.g. labels/brochures/fliers

Question 14

Laser printer advantages and disadvantages

Answer 14

+ much quicker than ink-jet

- more expensive than ink-jet

Question 15

Dot matrix printer

Answer 15

Strike an inked ribbon which imprints dots to form letters on the page
e.g printing in a dusty warehouse

Question 16

Dot matrix printer advantages and disadvantages

Answer 16

+ useful where multi-part stationary is required
+ can work in damp/dirty atmosphere
- can’t be used for images/colour
- noisy

Question 17

3D printers

Answer 17

Print using plastic filament, powdered resin, ceramic/metal powder or paper to make intricate objects including hollow areas

Question 18

RFID

Answer 18

Radio frequency ID
Powered receiver emits radio frequency energy, transponder becomes energised and sends data
e.g. contactless payment, security, ID

Question 19

Passive transponders

Answer 19

No power source, rely on radio waves from receiver for energy, transponders must be close
E.g. contactless payment

Question 20

Active transponders

Answer 20

Use a large battery powered beacon, 300m broadcast range

E.g. tracking products in a supermarket

Question 21

Actuators

Answer 21

Motors used in conjunction with sensors to control a machine

e.g. automatic doors

Question 22

Loudspeakers/headphones

Answer 22

Data sent from computer to DAC, boosted by an amplifier and sent to a speaker

Question 23

LCD monitors

Answer 23

Liquid crystal display screens
Contain groups of RGB diodes to form each pixel
Require backlighting with cold cathode fluorescent lights- CCFL

Question 24

LED

Answer 24

Used instead of CCFL in LCD monitors

Cheaper, lighter, brighter, quicker, less likely to break

Question 25

OLED screens

Answer 25

Organic LED
Use plastic rather than glass - flexible
Much brighter than LCD/LED
Generate their own light
Use much less power, less heat (lower fire risk)

Question 26

Multimedia light projectors

Answer 26

Compact, high-resolution full colour projectors

Project text, images, video and audio contenting