Input, Output, and Sensors

Question 1

output device

Answer 1

piece of hardware used to communicate the result of processed data

Question 2

examples of output devices

Answer 2

printers, cutters, actuator, monitors, speakers, projectors, and headphone

Question 3

printers

Answer 3

create (hard) copies of documents and images

Question 4

Inkjet printers

Answer 4

use ink cartridges to spray tiny droplets of ink at any paper to form an image

Question 5

Laser printers

Answer 5

uses a laser to apply a static charge to areas on the paper. Toner (a powdered ink) is then attracted to the static charge and sticks to the paper, forming an image

Question 6

3D printer

Answer 6

used in computer aided design to produce solid objects of various materials. Design is made using CAD

Question 7

When the printer runs out of paper

Answer 7

a signal called an interrupt is sent to the processor to request that the problem is dealt with

Question 8

Projector

Answer 8

Used to display images and videos on large areas. Useful when output needs to be viewed by many people

Question 9

LCD projectors (Liquid Crystal Display)

Answer 9

Creates an image by projecting light in three colors (RGB). Older technology.

Question 10

DLP projectors (Digital light processing)

Answer 10

Uses thousands of tiny mirrors to reflect a digital image. Comp -> screen. Smaller, more portable, lesser quality images

Question 11

LCD (Liquid Crystal Display)

Answer 11

Sandwich crystals between two sheets of glass. White backlight illuminates screen from behind. When crystals are solid, light cannot pass through. When an electrical current is applied to the crystals, light passes through, and an image is formed.

Question 12

LED (Light emitting diode)

Answer 12

LEDs use light emitting diodes to generate light. Better contrast.

Have a better image quality, use less power, more cost effective, initial cost is higher

Question 13

Speaker

Answer 13

Produce output inform of sound. Converts electrical signal into vibrations

Question 14

Actuator

Answer 14

Takes a digital signal and outputs it as a physical movement

Question 15

Cutters

Answer 15

Cut through materials such as glass

Coordinates are used to recognize the object

Question 16

input devices

Answer 16

Used to input data into a computer for processing

Question 17

examples of input device

Answer 17

keyboard, mouse, microphone

Question 18

Keyboard (text)

Answer 18

Connected to a computer via USB/wireless

Each character has an ASCII value.

Each character pressed is converted to a digital signal

Each ASCII value has a binary value

The binary can be processed by the CPU to action the key press

Slow method of data entry, prone to errors

Question 19

mouse (movement)

Answer 19

Mechanical ball, connected through USB port.

Question 20

Microphone (sound)

Answer 20

Sound reaches the microphone’s diaphragma, which is attached to an electromagnetic apparatus which senses the vibrations and produces an electric current.

Question 21

Touch Screen (movement, touch)

Answer 21

Useful when a user must select from a small range of options

Question 22

Resistive touch screen

Answer 22

Top layer is flexible plastic with conductive film

The second layer is hard, with film.

Spacers keep them from touching.

When the screen is touched, both layers touch.

Measuring resistance on both points, a measurement of the position is found

Completes electrical circuit.

+: Cheap to manufacture

-: Not durable, poor visibility in the sun, less accuracy.

Question 23

Capacitive touch screen

Answer 23

Transparent layer over screen, which is sensitive to the static electrical charge in human bodies.

When finger touches screen, current changes.

Change is detected and location can be detected. Point is sent back to controller.

+: Good visibility in the sun, durable, allows multitouch.

-: Glass screen can break, cannot be used with gloves.

Question 24

infrared touch screen

Answer 24

Creates a grid of infrared light over screen, transmitted using LEDs.

When the user touches the screen, light beams are broken.

This information can be used to detect the location of touch.

+: Can be touched with gloved finger and stylus pen, durability is good, allows multitouch.

-: Expensive to manufacture, sensitive to dirt/dust, screen will shatter on impact.

Question 25

Digital Camera: Images

Answer 25

Controlled by the microprocessor, which automatically adjusts shutter speed, focus, flash, etc.

Light passes through the lens onto a light sensitive cell made of pixels.

+: Images can be viewed immediately and can be edited easily on a computer.

-: Poor lens quality, limited memory for photo storage.

Question 26

QR Code scanner

Answer 26

Quick Response code: Consists of a square black and white pattern, representing binary.

It is captured by a camera/scanner that breaks it down into a grid.

Processed light is reflected.

Black reflects less than white

Squares are decoded.

+: Holds a lot of data, doesn’t need a connected database, can store a variety of info (URL, payments)

-: Not suitable for info that changes regularly, needs a device/software that can read it.

Question 27

Bar code scanner

Answer 27

A laser is shone at barcode; light is reflected to see if black or white.

Reflected light is read by sensor, pattern is converted into digital.

Used in categorizing and retrieval of store products.

Used in airports to track luggage.

+: Accurate and precise, reduces pricing error, improved customer service.

-: Possible misreads, barcodes need to be printed on labels and tags.

Question 28

2D Scanner: Images and text

Answer 28

Documents are placed on the glass.

Scan head moves across so image can be sent to a lens.

Lens deconstructs light.

CCD produces electrical charges.

Digital image is produced by software.

Used to create 2D images.

Used to read passports.

+: Very accurate, high quality, large variety, higher resolution compared to digital camera.

-: Uses a lot of computer’s storage, can lose some of its quality.

Question 29

3D Scanner: 3D objects

Answer 29

Scans objects using lasers to measure dimensions (h,w,l).

Laser detects details about shape and converts it into digital data.

+: Can scan tough surfaces, high resolution, and accuracy, less sensitive to changing light.

-: Shiny/transparent surfaces do not work.

Question 30

Interactive whiteboard: Pressure

Answer 30

Allows users to write on the surface using a pen.

Text and drawings are then captured electronically and stored for later use.

+: Easy to use, can access files to display.

-: Expensive to install and maintain.

Question 31

sensor

Answer 31

specific type of input device used to gather information about physical environment

Question 32

types of sensor

Answer 32

• motion/infrared
• pressure
• light
• pH
• gas
• humidity
• sound

Question 33

answer for sensors question

Answer 33

Sensor sends data readings to the microprocessor at set intervals.

To be understood, this data might need to be converted using an ADC (analogue to digital converter).

The microprocessor compares data readings against pre-set values it has stores (using a control program).

The microprocessor then makes a decision as to whether any action is needed.

If needed, the microprocessor will send a signal to instruct an output device to do something.

This may involve an actuator.

This process repeats in a continuous loop.

Question 34

acoustic sensor

Answer 34

An acoustic sensor detects sound. This might include sound that is too low-pitched, too high-pitched or too quiet for humans to hear. One application of an acoustic sensor would be a burglar alarm, which could be used to detect a break-in.

Question 35

accelerometer sensor

Answer 35

An accelerometer measures acceleration force (the rate of change of velocity). They are often used in smart phones to detect movement (for example, when a game is controlled by moving the phone itself).

Question 36

flow sensor

Answer 36

Flow sensors measure the flow speed of liquids or gases in pipes. This is important in many situations. For example, a reduced flow speed in a pipe might mean there is a leak or a blockage in the pipe, and a flow sensor can be used to detect this situation.

Question 37

gas sensor

Answer 37

Gas sensors can detect the presence of different gases. This is essential in many safety systems. For example, a gas sensor may be used to detect the presence of toxic gases in a chemical manufacturing plant.

Question 38

humidity sensor

Answer 38

A humidity sensor detects water vapour in the air. Humidity sensors can be used in air conditioning or environmental control systems. For example, a greenhouse might use a humidity sensor to help a computer determine if the environment is correct for the plants growing there.

Question 39

infra red sensor

Answer 39

An infra-red (IR) sensor is a type of light sensor that detects invisible infra-red light. Infra-red sensors are often used to measure the presence of objects. For example, an automatic door system might use an infra-red sensor to detect a person walking in front of the door.

Question 40

level sensor

Answer 40

A level sensor uses a gyroscope to measure angular movement. This enables the sensor to detect if it is being tilted or rotated. A common application for these sensors is in smart phones, which can be controlled by tilting or waving the device.

Question 41

light sensor

Answer 41

Light sensors detect light levels. This light could be visible light or invisible light, such as infra-red. Light sensors can be used in automatic lighting systems to switch on lights when natural light levels fall below a certain level.

Question 42

magnetic field sensor

Answer 42

A magnetic field sensor measures the strength of a magnetic field. They are sometimes used in geophysical surveys.

Question 43

moisture sensor

Answer 43

A moisture sensors measures the presence of water.

Question 44

pH sensor

Answer 44

A pH sensor detects how acidic or alkaline a substance is. pH sensors might be used in swimming pools or aquariums to check the pH of the water, or in a chemical factory to help ensure the pH level is correct.

Question 45

pressure sensor

Answer 45

A pressure sensor may refer to two different types of sensor:

A sensor which measures the pressure of a liquid or gas, such as in a pipe.

A sensor which means the weight pushing down on it, such as a floor plate which can detect the pressure of a person standing on it.

Question 46

proximity sensor

Answer 46

A proximity sensor can detect when an object is close, even if the objects are not touching. They are used in many situations where collisions need to be avoided. For example, many cars have proximity sensors to warn the driver when an object is very close to the front or rear of the car.

Question 47

temperature sensor

Answer 47

Temperature sensors measure heat energy. Many home appliances such as microwaves, kettles and washing machines contain temperature sensors. This helps ensure they are working correctly and safely.