Chapter 3

Question 024.0 Give an example of an active motion sensor?

Active microwave sensor See page 056 [v01.00]

Question 005.0 Define actuator

Actuator - this is a type of MOTOR that controls a mechanism or system. See page 055 [v01.00]

Question 050.0 Clearly explain the use of humidity sensors in Agriculture and Farming?

Agriculture and farming. Humidity and moisture sensors can be used to grow and farm crops in the best conditions possible. By monitoring and controlling the conditions in which the crops are grown, the most perfect conditions can be created, producing the best crops. The level of moisture in the soil can be kept constant to help the crops grow. See page 058 [v01.00]

Question 041.0 Humidity sensors monitor and measure the humidity that is in the (fill in the blank)?

Air. See page 058 [v01.00]

Question 022.0 A motion sensor detects movement. It can do this either passively or actively. Describe (in very general terms, without an example) how an active motion sensor works?

An active motion sensor emits energy into the surrounding environment to detect any movement. See page 056 [v01.00]

Question 003.0 Define analogue

Analogue - this is the smooth stream of data that we process on a daily basis. See page 055 [v01.00]

Question 038.0 Clearly explain the use of pressure sensors in the Aviation and marine industry? State which part is monitored and controlled using pressure sensors.

Aviation and marine industry. They are used to monitor and control the atmosphere within an aeroplane or submarine. This is to make sure that the correct breathing conditions are maintained. See page 057 [v01.00]

Question 065.0 What is the advantage (and disadvantage) of using a sensor or a number of sensors in a monitoring and control system taking multiple readings? Include how the computer will act logically and the quality of its decision making.

By using a sensor or a number of sensors in a monitoring or control system, multiple readings can be taken in quick succession. it would require people to perform the same function, and so these people can be made available to perform other tasks. The computer system will make decisions based on the data it is given. it will act logically on these decisions in the way it has been programmed. This can be beneficial as the decisions made and actions taken will be consistent. If a human performed the same decision-making process, external factors may affect the decision they make, for example how tired they are. This could cause inconsistency in the decision-making process and actions taken. This can sometimes be a disadvantage and a computer system may not be able to react to an unexpected event that a human would be able to assess and make a decision about. See page 059 [v01.00]

Question 029.0 Give an example of how a business can be made more environmentally friendly by using motion sensors?

By using motion detectors in various ways a business can be made more environmentally friendly. Using motion sensors, a business can make sure that lights are only turned on when a person is working in a room and they can also make sure that no water is left running. See page 057 [v01.00]

Question 037.0 Clearly explain the use of pressure sensors in Chemical and nuclear plants? State what is monitored.

Chemical and nuclear plants. They are used to monitor and control the flow of gases and liquids in industrial plants. This means that substances that are being transported in the plant, or any chemical reactions that are carried out, are done extremely safely. This makes sure that a high level of safety is maintained in the industrial plant at all times. See page 057 [v01.00]

Question 014.0 Monitoring and control technologies make use of many different sensors. What do CONTROL technologies use sensors for?

Control technologies use sensors to automatically control elements of a system, or a whole system, by using the data from them to TRIGGER an action or event. See page 055 [v01.00]

Question 048.0 Clearly explain the use of humidity sensors in Controlling allergies?

Controlling allergies. An atmosphere that is high in humidity can encourage the growth of bacteria and mould. This can trigger allergies. Humidity sensors can be used to monitor and control the level of humidity in a room. See page 058 [v01.00]

Question 055.0 Clearly explain the use of temperature sensors in a clothes dryer?

Dryer. A temperature sensor is used in a dryer to measure the temperature of the hot air flowing into the dryer. A microprocessor in the dryer will receive the data sent by the temperature sensor and can trigger an action to heat up or cool down the air if necessary. See page 058 [v01.00]

Question 064.0 Clearly describe why humans are not good at doing repeated actions (for example taking a reading over and over for long periods of time)?

For a human to complete a repeated action, for example taking a reading over and over for long periods of time, can be very arduous and it may prove difficult to maintain accuracy. A computer system that has a sensor that can perform this role is able to run for long periods of time, with a high level of accuracy. This level of accuracy can make a system more reliable than one operated by humans. See page 059 [v01.00]

Question 009.0 Define humidity

Humidity - the amount of water in the atmosphere. See page 055 [v01.00]

Question 042.0 What two things must be measured for humidity?

Humidity sensors monitor and measure the humidity that is in the air. To monitor the humidity they measure both 1 the moisture and 2 temperature in the air. See page 058 [v01.00]

Question 043.0 What is expressed as the level of humidity?

Humidity sensors monitor and measure the humidity that is in the air. To monitor the humidity they measure both the moisture and temperature in the air. The percentage of moisture present in the air at a certain temperature is expressed as the level of humidity. See page 058 [v01.00]

Question 044.0 Clearly describe the technology behind the humidity sensor that results in a change in voltage which is then converted into a measure of humidity?

Humidity sensors normally use capacitive measurement. This type of measurement uses two electrical conductors that have a non-conductive film separating them. Moisture collects on the film and changes the level of voltage between the electrical conductors. The measurement of the change in voltage is converted into a MEASUREMENT OF HUMIDITY. See page 058 [v01.00]

Question 006.0 Define infrared

Infrared - a wave of light emitted by an object that is invisible to the naked human eye. See page 055 [v01.00]

Question 002.0 Define input device

Input device - a device that allows data to be entered into a computer system See page 055 [v01.00]

Question 017.0 Can you tell when a control system is not just a monitoring system?

It is a control system as an action is TRIGGERED to control an element of the system as a result of the monitoring that is taking place. See page 056 [v01.00]

Question 049.0 Clearly explain the use of humidity sensors in Manufacturing?

Manufacturing. In the manufacturing of many products the level of moisture in the atmosphere is very important. If humidity is too high or too low it could adversely affect the product. See page 058 [v01.00]

Question 047.0 Clearly explain the use of humidity sensors in Meteorological stations?

Meteorological stations. They are used to help monitor and predict weather conditions by measuring humidity levels. See page 058 [v01.00]

Question 004.0 Define microprocessor

Microprocessor - an integrated circuit used in monitoring and control technologies See page 055 [v01.00]

Question 007.0 Define microwave

Microwave - an electromagnetic wave of energy See page 055 [v01.00]

Question 019.0 A monitoring system outputs results in a different way. Rather than an action being triggered, the results of the readings taken from the monitoring can be output in the form of graphs or charts. Describe how monitoring systems are used in scientific experiments?

Monitoring systems can be used in scientific experiments. The experiments are often left to run for periods of time, with a monitoring system taking readings at regular intervals. The readings are then output and can be analysed. This kind of technology removes the need for a human to regularly take the readings. This means that the readings can be taken over long periods of time and can often be more accurate if taken by a system. See page 056 [v01.00]

Question 013.0 Monitoring and control technologies make use of many different sensors. What do MONITORING technologies use sensors for?

Monitoring technologies use sensors to monitor an environment, often collecting data about the environment. See page 055 [v01.00]

Question 032.0 What is the name of the principle that most modern pressure sensors use?

Most modern pressure sensors use a principal called piezoresistance. See page 057 [v01.00]

Question 033.0 Without an example, clearly describe what is meant by the principle called piezoresistance which most modern pressure sensors are based upon?

Most modern pressure sensors use a principal called piezoresistance. ln piezoresistance, a specific level of pressure is linked to a specific level of charge through a substance. If a change in the level of charge is detected, this is interpreted as a change in pressure. See page 057 [v01.00]

Question 027.0 Since motion sensors are not error proof what can happen?

Motion sensors are not error proof and can sometimes cause a false alarm to sound. See page 056 [v01.00]

Question 023.0 Give an example of a passive motion sensor?

Passive infrared sensor See page 056 [v01.00]

Question 026.0 Clearly describe how a passive INFRARED sensor detects motion in a security system?

Passive infrared sensors are commonly used in security systems. These sensors are normally wall mounted in the corner of a room. As an intruder walks in front of a sensor, the sensor detects the infrared energy EMITTED by the INTRUDER. The detection of infrared energy by the sensor can then trigger an alarm to sound. See page 056 [v01.00]

Question 010.0 Define photoresistor

Photoresistor - a light controlled resistor. See page 055 [v01.00]

Question 008.0 Define piezoresistance

Piezoresistance - a specific level of electrical charge that is linked to a specific level of resistance or pressure See page 055 [v01.00]

Question 035.0 Clearly explain an example of the use of a pressure sensor that uses piezoresistance?

Pressure sensors can be used in things such as pipes to measure the flow of liquid or gas through them, to make sure they do not flow too quickly. See page 057 [v01.00]

Question 056.0 Clearly explain the use of temperature sensors in a refrigerator and freezer?

Refrigerator and freezer- A temperature sensor is used in a refrigerator or freezer to measure the ambient temperature inside. A microprocessor in the refrigerator or freezer will receive the data sent by the temperature sensor and can trigger an action to heat up or cool down the air if necessary. See page 058 [v01.00]

Question 001.0 Define sensor

Sensor - a device that records data about the surrounding physical environment. A sensor is an input device that records data about the surrounding physical environment. The sensor inputs this data into a computer system to be processed. Once the data has been processed, if necessary, an output can be triggered as a response See page 055 [v01.00]

Question 066.0 What type of environments are sensors extremely beneficial to humans?

Sensors are also extremely beneficial for use in environments that are dangerous to humans. This means that we can be kept safe yet dangerous environments can still be monitored. Also, computers can process data much more quickly and respond faster to any necessary actions than a human, so a dangerous environment can be monitored and controlled more effectively. See page 059 [v01.00]

Question 011.0 Explain clearly how sensors allow for increased accuracy

Sensors can automatically enter data into a computer system, removing the need for a human to manually enter the data. They can be very beneficial as it can increase the accuracy of the data by removing the possibility of human error. See page 055 [v01.00]

Question 012.0 Give 2 examples of how sensors are useful in dangerous environments

Sensors can be very beneficial in environments that could be harmful and dangerous for a human, for example 1 in a nuclear plant to detect radiation levels, or 2 inside an active volcano to detect changes in activity. See page 055 [v01.00]

Question 052.0 What do temperature sensors measure?

Temperature sensors monitor and measure the temperature of an environment. They do this by measuring how much heat is present. Temperature sensors are used in a great number of control systems, many of them in our home appliances. See page 058 [v01.00]

Question 060.0 Clearly describe what a digital camera uses a light sensor for?

The camera can adjust the level of flash needed depending on the level of light currently detected by the light sensor. See page 059 [v01.00]

Question 031.0 In general terms a pressure sensor normally measures pressure of a liquid or a gas. What FORCE is this measure of pressure based upon?

The measure of pressure is based upon the force it takes to stop a liquid or gas from expanding. See page 057 [v01.00]

Question 058.0 There are many different types of light sensor that monitor and measure light in different ways. What is the most common type of light sensor?

The most common type of light sensor is a photoresistor. This type of light sensor will change its resistance when light shines on and is normally used to measure the intensity of light. See page 058 [v01.00]

Question 059.0 Clearly and carefully describe how the type of light sensor known as a photoresistor works?

The most common type of light sensor is a photoresistor. This type of light sensor will change its resistance when light shines on and is normally used to measure the intensity of light. See page 058 [v01.00]

Question 063.0 Describe why the use of sensors in computer system can benefit humans, greatly

The use of sensors in computer systems can benefit us greatly. This remove the need for a human to monitor and measure an environment as this can be done continuously by the sensor. This can leave us to get on with other tasks that we need to complete. It can also mean that the monitoring and measuring is more accurate. See page 059 [v01.00]

Question 067.0 Why is there always a risk when using computer systems in monitoring and control?

There is always a risk involved in using computer systems in monitoring and control. The system is electronic and if a power failure occurs, the system will not operate. If the system is controlling a crucial process, this could have a detrimental effect. This could also happen with a simple system malfunction. See page 059 [v01.00]

Question 036.0 Clearly explain the use of pressure sensors in the vehicle industry? State which liquids are monitored and which 3 parts of the system are involved?

They are used to form part of the safety system of a vehicle. Pressure sensors are used to monitor 1 the oil and coolant in the vehicle. They are used to regulate 2 the power given to the engine based on the pressure placed on the accelerator and brake. 3 The airbag safety system also uses pressure sensors. The air bags will be triggered to inflate when a high amount of pressure is applied to certain parts of the vehicle. See page 057 [v01.00]

Question 039.0 Clearly explain the use of pressure sensors in Touch screens? What is used to detect touch on some touch screens. State the type of signal that is involved.

Touch screens. A touch screen that uses pressure sensors is built up of multiple layers. When pressure is applied to the top layer of the screen it is pushed into the bottom layer of the screen, creating a connection that generates an electrical signal. This electrical signal informs the device of the location where the pressure has been applied to the screen. See page 057 [v01.00]

Question 054.0 Clearly explain the use of temperature sensors in a washing machine and dishwasher?

Washing machine and dishwasher- A temperature sensor is used in a washing machine and a dishwasher to measure the temperature of the water. A microprocessor in the washing machine or dishwasher will receive the data sent by the temperature sensor and can TRIGGER an action to heat up or cool down the water if necessary. See page 058 [v01.00]

Question 046.0 Clearly explain the use of humidity sensors in Wine cellars?

Wine cellars. The humidity level in the atmosphere of a wine cellar is very important. Too much or too little humidity can cause the wine to spoil. The humidity level needs to be kept at a constant and correct level in order to keep the wine at its best. See page 058 [v01.00]

Question 028.0 Motion sensors can be used in lots of monitoring and control systems. List 5 of them?

1 CCTV systems, to manoeuvre the camera to the direction of motion that is detected 2 opening and closing automatic doors 3 automatically turning lights on or off in a room when a person enters or leaves 4 automatically turning water taps on or off 5 automated barriers in a car park. See page 056 [v01.00]

Question 034.0 List the different monitoring and control technologies that pressure sensors can be used in?

1 The vehicle industry 2 Chemical and nuclear plants 3 Aviation and marine industry 4 Touch screens. See page 057 [v01.00]

Question 053.0 List the places that temperature sensors are used in control systems (5 home appliances)?

1 Washing machine 2 Dishwasher 3 Clothes dryer 4 Refrigerator 5 Freezer. See page 058 [v01.00]

Question 045.0 List the 5 situations both in the home and the workplace that humidity sensors can be used to monitor and control humidity levels?

1 Wine cellars 2 Meteorological stations 3 Controlling allergies 4 Manufacturing 5 Agriculture and farming See page 058 [v01.00]

Question 062.0 List 5 devices in which you would find a light sensor

1 barcode 2 scanners 3 display screens 4 automated lighting systems and 5 smartphones. See page 059 [v01.00]

Question 016.0 List the 5 steps that the control software in an automated street light would follow

1. A light sensor will constantly monitor the level of light present in the surrounding environment. 2. The analogue data from the reading will be converted to a digital value by an analogue to digital converter. 3. The digital signal is sent to a microprocessor and the microprocessor will compare the value to a pre-set range. 4. If the value is outside the preset range, the microprocessor sends a signal to an actuator that will trigger the action to turn the street light on or off. 5. The whole process will then be repeated See page 055 [v01.00]

Question 020.0 List the 5 main sensors used in monitoring and control technologies

1. Motion sensors 2. Pressure sensors 3.Moisture and humidity sensors 4. Temperature sensors 5. Light sensors. See page 056 [v01.00]

Question 030.0 List the 5 main sensors used in monitoring and control technologies

1. Motion sensors 2. Pressure sensors 3.Moisture and humidity sensors 4. Temperature sensors 5. Light sensors. See page 056 [v01.00]

Question 051.0 List the 5 main sensors used in monitoring and control technologies

1. Motion sensors 2. Pressure sensors 3.Moisture and humidity sensors 4. Temperature sensors 5. Light sensors. See page 056 [v01.00]

Question 040.0 List the 5 main sensors used in monitoring and control technologies

1. Motion sensors 2. Pressure sensors 3.Moisture and humidity sensors 4. Temperature sensors 5. Light sensors. See page 058 [v01.00]

Question 057.0 List the 5 main sensors used in monitoring and control technologies

1. Motion sensors 2. Pressure sensors 3.Moisture and humidity sensors 4. Temperature sensors 5. Light sensors. See page 058 [v01.00]

Question 015.0 List the 4 steps of how (either) monitoring or control systems operate

1. The sensor will constantly monitor the surrounding environment 2. The data readings from the sensor will normally be analogue. Therefore, they will be converted to a digital signal for a computer system to process. This is done by an analogue to digital converter 3. The digital signal is then sent to a microprocessor. The microprocessor processes the value and compares it to a pre-set value or range of values 4. If the value is outside the acceptable range, the microprocessor will send a signal to an actuator to trigger any action that needs to be taken. See page 055 [v01.00]

Question 025.0 Clearly describe how an active MICROWAVE sensor detects motion in a security system?

A microwave sensor continuously emits microwaves into a room. As an intruder walks through the microwaves, they will be REFLECTED back much more quickly to the sensor and it will detect the change. This change in reflection of the microwaves can then cause an alarm to sound. See page 056 [v01.00]

Question 018.0 What is output from a monitoring system (describe how this is different to the outputs of a control system)

A monitoring system outputs results in a different way. Rather than an action being triggered, the results of the readings taken from the monitoring can be output in the form of graphs or charts. This allows the readings to be compared and any patterns or trends to be identified. This information can then be used to inform any future decision making. See page 056 [v01.00]

Question 021.0 A motion sensor detects movement. It can do this either passively or actively. Describe (in very general terms, without an example) how a passive motion sensor works?

A passive motion sensor reads the energy in its surrounding environment and detects changes caused by movement See page 056 [v01.00]

Question 061.0 Clearly describe what a street light uses a light sensor for?

A street light can detect when it gets dark enough to need to switch the light on. See page 059 [v01.00]