← IGCSE Computer Science Paper 1

What an automated system is

A system that senses its surroundings, decides what to do and acts, without a person controlling each step. For example, an automatic door.

Part of: IGCSE Computer Science 0478 — 6.1 Automated Systems — Module 1, QCE Digital Solutions Unit 1 — Understanding Digital Problems — Module 21, QCE Digital Solutions Unit 3 — Interactions Between Users, Data and Digital Systems — Module 74

Understanding What an automated system is in IGCSE Computer Science Paper 1

What it does: The cycle sense, decide, act describes what every automated system does without a person controlling each step. The system decides by testing the sensor reading against a stored value, and then acts if the test is true. The sensor only senses (the input). The actuator is the part that opens the door. The microprocessor processes the sensor data and decides what to do. The sensor only gathers data. The street light senses the darkness and switches on by itself. The desk lamp needs a person to act. Acting is the output step, done by an actuator. Measuring the surroundings is the 'sense' step.

Common mistakes: The first step of an automated system is to sense. The program should read the sensor with READ_SENSOR(), not call the action OPEN_DOOR() to get the reading. The decision step needs THEN after the condition. It should be IF reading > 25 THEN so the system can decide whether to act.

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This module's key terms are also in a printable crossword (Modules 553–577) and word search (Modules 553–607).

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Learning
Duo
Which describes an automated system?
It senses, decides and acts without a person controlling each stepIt only works when a person presses a button for every step
Matches
A system is automated if a person presses a button for every step
↓
If a person controls every step it is manual control, not an automated system. An automated system senses, decides and acts by itself.
Applying
Meanings
Term
automated system
Meaning
A system that senses its surroundings, decides what to do and acts, without a person controlling each step. For example, an automatic door.
Practice
REPEAT
Testing
Gaps
IF doorSensor = TRUE
Check Answer
Spots
1reading ← OPEN_DOOR()
2IF reading = 1 THEN

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Quick Questions

1. Which describes an automated system?
A. It only works when a person presses a button for every step
B. It senses, decides and acts without a person controlling each step ✓
An automated system carries out the sense, decide and act steps by itself, so no person is needed for each step.
2. An automatic door opens when someone walks up to it. What does the sensor do?
A. Opens the door by pushing it
B. Senses that a person is near the door ✓
The sensor only senses (the input). The actuator is the part that opens the door.
3. Which is an example of manual control?
A. A person turns a tap on and off by hand ✓
B. A door opens by itself when it senses a person
In manual control a person carries out each action. The automatic door is an automated system.
4. In an automated system, which part makes the decision?
A. The microprocessor, using the sensor data ✓
B. The sensor, by moving the door
The microprocessor processes the sensor data and decides what to do. The sensor only gathers data.
5. Which list shows the steps of an automated system in the correct order?
A. Sense, decide, act ✓
B. Act, sense, decide
The system senses its surroundings first, decides what to do, and then acts, for example by opening a door.

Match the Pairs

automated system → A system that senses its surroundings, decides what to do and acts, without a person controlling each step
manual control → A person has to carry out each step themselves, such as pushing a door open by hand
An automatic door senses a person, decides to open and acts by moving the door, with no one pressing a button → sense -> decide -> act
The decision step compares the sensor reading with a stored value to choose what to do → IF reading > limit THEN open
A system is automated if a person presses a button for every step → If a person controls every step it is manual control, not an automated system. An automated system senses, decides and acts by itself.
An automated system acts first and then senses its surroundings → The order is wrong. An automated system must sense first, then decide, then act.

Key Term

automated system
A system that senses its surroundings, decides what to do and acts, without a person controlling each step. For example, an automatic door.

Fill in the Blanks

1. IF doorSensor = TRUE THEN openDoor() ENDIF
Hint: Type the keyword that follows the condition and introduces the action the system carries out.
2. IF temperature > 25 THEN fanOn() ENDIF
Hint: Type the comparison operator that checks whether the sensor reading is above the stored limit.
3. IF lightLevel < 20 THEN lightOn() ENDIF
Hint: Type the keyword that starts the decision step after the sensor reading is taken.
4. IF personDetected = TRUE THEN openDoor() ENDIF
Hint: Type the Boolean value the sensor gives when it senses that someone is there.
5. WHILE systemOn = TRUE checkSensor() ENDWHILE
Hint: Type the loop keyword that keeps the system repeating its checks so no person has to start each step.

Spot the Error

Question 1
A reading ← OPEN_DOOR()
B IF reading = 1 THEN
C OPEN_DOOR()
D ENDIF
Line A — The first step of an automated system is to sense. The program should read the sensor with READ_SENSOR(), not call the action OPEN_DOOR() to get the reading.
Question 2
A reading ← READ_SENSOR()
B IF reading > 25
C TURN_ON_FAN()
D ENDIF
Line B — The decision step needs THEN after the condition. It should be IF reading > 25 THEN so the system can decide whether to act.
Question 3
A light ← PRESS_SWITCH()
B IF light < 30 THEN
C SWITCH_ON_LAMP()
D ENDIF
Line A — An automated street lamp senses the light level itself. It should use READ_LIGHT_SENSOR(), not rely on a person pressing a switch.
Question 4
A WHILE TRUE
B distance ← ASK_DRIVER()
C IF distance < 2 THEN
D STOP_CAR()
E ENDIF
F ENDWHILE
Line B — No person should be needed for each step. The system should sense the distance with READ_SENSOR(), not ask the driver.
Question 5
A WHILE TRUE
B level ← READ_MOISTURE()
C IF level < 20 THEN
D READ_MOISTURE()
E ENDIF
F ENDWHILE
Line D — The act step should switch on the actuator. Reading the moisture sensor again does nothing to water the soil. It should be START_PUMP().

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