Input devices

Question 1

Input device

Answer 1

A device that allows data to be entered into a computer system

Question 2

2D scanner

Answer 2

Shines light onto the surface of a document
scan head moves across document
Reflected light is captured using mirrors and lenses to focus image onto a CCD
The captured image is converted into a digital file
It produces a 2d digital file

Question 3

3D scanner

Answer 3

Scanner shines a laser/light over the surface of the 3d object
Camera records the measurements of the dimensions of the object by detecting reflection of light
The measurements are converted into a digital file
It produces a 3d digital model

Question 4

Bar code reader

Answer 4

Reader shines a light/red laser at barcode
Sensors(photoelectric) cells detect light reflected back (white lines reflect more)
different reflections convert to different binary values
microprocessor interprets the data

unique code is searched in product database and identified

Question 5

QR code reader

Answer 5

Quick response code

QR code is captured by a camera
processed by an app
data is decoded into binary values
position and alignment markers are used for alignment

Question 6

7 ways a barcode help manage a supermarket stock

Answer 6

1. barcode identifies unique product
2. barcode can be used to look up product in a database
3. stock can be automatically deducted from the system
4. can check stock level
5. automatically re-orders when stock is low
6. automatically updates new stock level
7. locates if an item of stock is available in another location

Question 7

Bar Code vs QR code

Answer 7

Barcode:
1d
uses vertical lines
some need to be lined up

QR:
2d
contains squares
more data can be stored(7000 vs 30)
can be read from any angle
faster to scan

Question 8

digital camera

Answer 8

Shutter opens and lets light onto the CCD sensor at the back of the lens
intensity and colour of light is measured by millions of tiny sensors arranged in a grid
converted to binary values
stored as an image in the cameras memory

Question 9

Advantage of conventional keyboard

Answer 9

simple and easy to use

Question 10

Disadvantages of conventional keyboard

Answer 10

slow if not trained

greater potential for mistakes

Question 11

4 advantages of Concept keyboard

Answer 11

fewer errors
faster
less training
less vulnerable to dirt/food damage

Question 12

Disadvantages of Concept keyboard

Answer 12

not suitable for large amounts of choices

not suitable for all tasks

Question 13

mechanical mice

Answer 13

rubber ball under the mouse moves around on a hard surface

sensors work out the orientation

Question 14

optical mouse

Answer 14

red LED and a sensor determines the movement of the mouse as it passes of patterns on the surface

Question 15

3 advantages of mechanical mice

Answer 15

takes up little desk space
fine control
can be integrated into keyboard

Question 16

Disadvantges of mechanical mice

Answer 16

expensive

have to spend time getting used to it

Question 17

Conventional Keyboard

Answer 17

When a key is pressed, the small bar under the key pushes through a small hole and makes contact with a conducting membrane
signal is sent to computer

Question 18

3 advantages of Touchscreen

Answer 18

output and input occupy same space
simple and easy to use
works well with icons

Question 19

2 disadvantages of Touchscreen

Answer 19

low precision

difficult to use if damaged

Question 20

Capacitive touchscreen

Answer 20

Made up of many layers of glass coated with conductive material that act as a capacitor(current flows from all 4 corners of the screen)
As your finger comes close to a capacitor it changes the local electrostatic field
The system constantly monitors each capacitor to discover where the finger touched the screen
Sensors are located around the screen
Coordinates of touch are then calculated

Question 21

3 Advantages of capacitive touchscreen

Answer 21

good visibility in sunlight
durable surface
allows multi-touch

Question 22

2 disadvantages of capacitive screen

Answer 22

screen will shatter on impact

doesn’t work with gloves

Question 23

Resistive touch screen

Answer 23

2 layers
One flexible plastic surface with thin film of conductive material on underside
separated from a layer of glass coated in conductive material
separated by tiny spacers
when touched, the plastic deforms and the 2 conductive films meet so electric current changes
Calculation(resistance of both layers at contact) is carried out on where layers are connected

Question 24

2 advantages of resistive touch screen

Answer 24

cheap to manufacture

can use stylus/gloves

Question 25

4 disadvantages of resistive touch screen

Answer 25

poor visibility in sunlight
vulnerable to scratching
wears through time
doesn’t allow multi-touch

Question 26

Infrared touch screen

Answer 26

The screen has grid of infrared LED beams
Sensors(photocells) detect where the beam is broken
The position of the touch is calculated

Question 27

3 advantages of infrared touch screen

Answer 27

good durability
allows multi-touch
can use stylues/gloves

Question 28

3 disadvantages of infrared touch screen

Answer 28

expensive to manufacture
other other objects can trigger touch
sensitive to dirt/dust

Question 29

3 advantages of interactive whiteboard

Answer 29

large display allows multiple people to work
interactivity helps with presentation and learning
text/drawings can be captured and stored for later

Question 30

3 disadvantages of interactive whiteboard

Answer 30

requires an interactive board, projector & computer
low precision
poor visibility in sunlight

Question 31

Microphones

Answer 31

When sound reaches the microphone a diaphragm vibrates back and forth
This causes the coil to vibrate which changes the magnetic field produced by the magnet
This produces an electric(analogue) signal
This signal goes to a ADC and converted to into a digital value

Question 32

4 advantages of Microphones

Answer 32

digital sound can be edited
allows disabled user to give instructions to a computer
allows voice and video calls
enables speech recognition software

Question 33

1 disadvantage of Microphone

Answer 33

Speech recognition accuracy is hit and miss

Question 34

Voice recognition

Answer 34

identifies if known person is speaking

wave patterns that from a persons voice are compared with stored patterns

Question 35

Speech recognition

Answer 35

Converts speech patterns into digital form
Broken up phonemes are compared with words stored in a dictionary
Words can then be recognised

Question 36

8 Types of Sensor

Answer 36

Temperature
moisture/humidty
light
infrared/motion
acoustic
gas
pH
magnetic field

Question 37

Operation of input sensors

Answer 37

1. … sensor takes constant readings of the rooms conditions
2. The reading is converted from analogue to digital using an ADC
3. The data is sent to the microprocessor
4. The microprocessor compares the value to stored pre-set values
5. If the value is outside range/matches…
6. the microprocessor sends a signal to {…}
7. Monitoring (and control) is continuous

Question 38

moisture sensor vs humidity sensor

Answer 38

Moisture sensor: the amount of moisture in a certain material
Humidity sensor: the amount of moisture in the ai