Automated systems Cambridge IGCSE Computer Science revision
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In plain words
An automated system does a job without a person operating it: street lights that come on at dusk, a greenhouse that waters itself, a car that brakes when it gets too close to the one in front.
Every one of them is the same loop of three parts: something that measures, something that decides and something that acts.
6 things to know
- An automated system uses sensors, a microprocessor and actuators working together.
- The sensor takes a reading and sends it to the microprocessor. If the reading is analogue, it is converted to digital first.
- The microprocessor compares the reading with stored values. If action is needed, it sends a signal to an actuator.
- The actuator makes something happen: it switches on a light, opens a valve or applies a brake. Then the process repeats, continuously.
- Advantages: automated systems can be faster and more consistent than people, can work all the time, and can work where it is dangerous.
- Disadvantages: they are expensive to set up and maintain, they can replace people's jobs, and they cannot deal with situations they were not programmed for.
Worked example
Describe how an automated system switches street lights on when it gets dark.
- A light sensor measures the light level and sends the reading to the microprocessor.
- The microprocessor compares the reading with a stored value.
- If the reading is below the stored value, it is dark, so the microprocessor sends a signal to an actuator that switches the lights on.
- The process repeats continuously.
Tips and tricks
- The sensor only measures. It is the microprocessor that compares and decides. Never write "the sensor decides".
- Finish every description with "this process is repeated" or "continuously". It is usually worth a mark.
It lands in your notebook with its questions as flashcards.
Automated systems: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which three components work together in an automated system?
Measure, decide, act.
In an automated system, what compares a reading with a stored value?
The sensor measures. The microprocessor decides.
What does the actuator do in an automated system?
It acts on the microprocessor's signal.
Which is an advantage of an automated system?
It keeps going all day and night.
Which is a disadvantage of automated systems?
They also need maintaining.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
2 questions, 7 marks. Write your answers on paper, then check them.
Automated systems
Cambridge IGCSE Computer Science 0478 · 7 marks · papermunch.org
Name ______________________________ Date ______________
Describe how sensors, a microprocessor and actuators are used to keep a greenhouse at the right temperature.[5]
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A temperature sensor sends readings to the microprocessor. The readings are converted from analogue to digital. The microprocessor compares each reading with a stored value. If it is too low, a signal is sent to an actuator to turn the heater on (and if too high, to open a window). The process is repeated continuously.
Give one advantage and one disadvantage of using an automated system in a factory.[2]
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Advantage: it can work all day and night without getting tired. Disadvantage: it is expensive to buy and set up.
Answers: Automated systems
- 1. A temperature sensor sends readings to the microprocessor. The readings are converted from analogue to digital. The microprocessor compares each reading with a stored value. If it is too low, a signal is sent to an actuator to turn the heater on (and if too high, to open a window). The process is repeated continuously.
- 2. Advantage: it can work all day and night without getting tired. Disadvantage: it is expensive to buy and set up.