Year 11 · Computer Science · Autumn 2 – mid-December
Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Automated systems
Practical6.1 Automated systems
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
You will learn to
- Explain how sensors, a microprocessor and actuators work together in an automated system.
- Describe the control loop of the temperature build, step by step.
- Evaluate automated systems in industry, transport, agriculture, weather, gaming, lighting and science.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Success criteria
You have got it when you can say:
- I can say which part of our build is the sensor, the microprocessor and the actuator.
- I can describe the loop: read, convert to digital, compare with a stored value, act, repeat.
- I can give one advantage and one disadvantage for each of the seven scenarios.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Retrieval starter
Questions from before. Write your answers, then show them.
- Last unit
Each block in a blockchain contains…
A Only a passwordB A pictureC A hash of the previous block, so any change shows
C. A hash of the previous block, so any change shows
- Last unit
DNS…
A Stores cookiesB Encrypts the pageC Turns a domain name into an IP address
C. Turns a domain name into an IP address
- Earlier this year
Which is a low-level language?
A PythonB JavaC Assembly language
C. Assembly language
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Key words (1 of 2)
- Automated system
- Hardware and software that do a task without a person controlling them.
- Sensor
- An input device that measures a physical quantity, such as temperature or light.
- Microprocessor
- A processor on a single chip that processes data and makes decisions.
- Actuator
- An output device that causes movement or switches something, such as a motor, valve or heater.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Key words (2 of 2)
- Set value
- The target value stored in the system that sensor readings are compared with.
- ADC
- Analogue-to-digital converter: changes an analogue sensor signal into digital data.
- Robot
- A programmable machine with a mechanical structure, sensors, microprocessors and actuators.
The explanation · step 1 of 6 · part 1 of 3
The three parts of an automated system
An automated system is a mix of hardware and software that does a job without a person controlling it.
A sensor is an input device that measures something physical, such as temperature or light, and sends the reading as data.
A microprocessor is the processor on a single chip. It compares the sensor reading with a stored set value (the target) and decides what to do.
An actuator is an output device that makes something move or switch, such as a motor, a valve, a heater or a pump.
The explanation · step 1 of 6 · part 2 of 3
The three parts of an automated system (continued)
| Part | Job | Examples |
|---|---|---|
| Sensor | Measures and inputs data | Temperature, light, moisture, pressure, infra-red, pH |
| Microprocessor | Compares the data with the set value and decides | The chip inside a thermostat or a car |
| Actuator | Carries out the action | Motor opening a window, valve releasing water, heater, pump |
The explanation · step 1 of 6 · part 3 of 3
The three parts of an automated system (continued)
Most sensors give an analogue signal (a smooth range of values). A microprocessor only works with digital data, so an analogue-to-digital converter (ADC) changes the reading first. Some actuators need a DAC to turn the output back into analogue.
A sensor does not decide anything. It only measures. The microprocessor makes the decision.
The explanation · step 2 of 6 · part 1 of 4
The control loop, step by step
An automated system runs a loop. It keeps checking and correcting, all day, without stopping.
Use the greenhouse toy. Drag the temperature reading, or change the set values (heater on below, window opens above). Press Run one loop and watch the microprocessor compare them and switch the actuators on or off.
To match the example below, set Window opens above to 24 and drag the temperature to 27.
The explanation · step 2 of 6 · part 2 of 4
The control loop, step by step (continued)
In the exam, write the steps in this order: sensor reads, ADC converts, microprocessor compares with the set value, actuator acts, the loop repeats.
The explanation · step 2 of 6 · part 3 of 4
The control loop, step by step (continued)
The explanation · step 2 of 6 · part 4 of 4
The control loop, step by step (continued)
The loop is what makes the system automatic. Every new reading can change the action, so the conditions stay close to the target.
Do not write "the sensor opens the window" or "the sensor decides it is too hot". Sensors only send readings.
There is something to try for this step in the IGCSE library.
The explanation · step 3 of 6
Scenarios: industry and transport
In industry, automated systems control production lines, chemical plants and power stations.
In transport, they control trains, traffic lights and parts of cars, and they are the basis of self-driving vehicles.
| Scenario | How it works | Advantages | Disadvantages |
|---|---|---|---|
| Industry: chemical plant | Temperature and pressure sensors feed a microprocessor; it opens valves and controls pumps to keep a reaction safe | Works 24/7; faster and more consistent; safer for workers in dangerous places | Expensive to set up; job losses; a fault can stop all production |
| Transport: driverless metro train (for example Barcelona Metro Line 9) | Sensors detect the train's position and speed, and obstacles on the track; the microprocessor controls the motors, brakes and doors | Trains run closer together and on time; no human error from tiredness; lower running costs | Very costly to build; risk of hacking; passengers may feel unsafe with no driver |
| Transport: self-driving car | Cameras, radar and lidar sensors feed microprocessors that control steering, brakes and accelerator | Can react faster than a human; may reduce accidents | Expensive; software errors can cause crashes; who is to blame after an accident is unclear |
The explanation · step 4 of 6
Scenarios: agriculture and weather
In agriculture, automated systems water crops, feed animals and control greenhouses.
In weather monitoring, automated stations take readings day and night in remote places.
| Scenario | How it works | Advantages | Disadvantages |
|---|---|---|---|
| Agriculture: automatic irrigation | Moisture sensors in the soil; if the reading is below the set value, the microprocessor opens a valve or starts a pump | Saves water; crops get exactly what they need; less labour | Set-up cost; sensors can fail or be damaged; needs power and maintenance |
| Agriculture: milking or feeding robots | Sensors identify each cow and measure milk flow; actuators attach equipment and give the right feed | Animals can be milked when they choose; data on each animal's health | Very expensive; farmers need technical skills to fix faults |
| Weather station | Temperature, humidity, pressure, light and wind sensors take readings at set times; data is sent to a central computer | Works 24/7 in remote or dangerous places; many accurate readings; better forecasts | Equipment can be damaged by storms; needs a power supply and a data connection |
The explanation · step 5 of 6 · part 1 of 2
Scenarios: gaming, lighting and science
In gaming, sensors in controllers and headsets turn movement into actions in the game.
In lighting, light and infra-red sensors switch lights on and off by themselves.
In science, automated systems run experiments and take readings for long periods.
The explanation · step 5 of 6 · part 2 of 2
Scenarios: gaming, lighting and science (continued)
| Scenario | How it works | Advantages | Disadvantages |
|---|---|---|---|
| Gaming: VR headset or motion controller | Accelerometers and gyroscopes sense movement; the microprocessor updates the game; actuators make the controller vibrate (haptic feedback) | More realistic, immersive experience; encourages movement | Expensive; motion sickness; sensors may lose accuracy |
| Lighting: street lights or a school corridor | A light sensor detects darkness, or an infra-red sensor detects movement; the microprocessor switches the lights on, and off after a set time | Saves electricity and money; better safety at night | Lights may switch off while someone is still there; sensor faults leave areas dark |
| Science: lab experiment | Sensors (temperature, pH, gas) take readings at set intervals for days; the microprocessor logs data and controls heaters or pumps | Readings are more accurate and taken at exact times; works overnight; safe with dangerous chemicals | Costly equipment; an unnoticed fault ruins the whole experiment |
The explanation · 1 more step
More on the lesson page
The lesson page has the rest of the explanation, step by step:
- Advantages and disadvantages in general
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Quick quiz · 1 of 3
In a greenhouse system, the actuator is…
- A The comparison with 20 °C
- B The temperature sensor
- C The heater valve that opens
C. The heater valve that opens
Sensor measures, microprocessor decides, actuator acts.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Quick quiz · 2 of 3
The microprocessor's job in an automated system is to…
- A Open the window
- B Compare the reading with a set value and decide
- C Measure the temperature
B. Compare the reading with a set value and decide
A sensor cannot decide. An actuator cannot decide. The microprocessor does.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Quick quiz · 3 of 3
An expert system's rule base holds…
- A IF–THEN rules
- B The sensors
- C The user's name
A. IF–THEN rules
The knowledge base holds facts; the rule base holds the rules.
Year 11 · Computer Science · Automated and emerging technologies; Paper 1 practice · Lesson 1 of 5
Exit ticket
Answer on paper before you go. Then check.
The part of an expert system that applies the rules is the…
A Inference engineB Knowledge baseC User interface
A. Inference engine It reasons from the facts and the rules to an answer.
Machine learning means…
A A programmer types every ruleB The system changes its own rules from dataC A robot with wheels
B. The system changes its own rules from data More and better training data gives a better model.