← IGCSE Computer Science Paper 1

Pressure sensor

An input device that measures the force applied over an area by a gas, liquid or solid, e.g. in tyre pressure monitors, weather forecasting and pressure pads.

Part of: IGCSE Computer Science 0478 — 3.2 Input and Output Devices — Module 45, IGCSE Computer Science 0478 — 6.1 Automated Systems — Module 14

Understanding Pressure sensor in IGCSE Computer Science Paper 1

What it does: Falling air pressure is used to predict changing weather, so the program reads the pressure sensor value and decides on a forecast. A pressure pad is a pressure sensor. When the force on the pad rises above zero, the microprocessor triggers an output such as an alarm. Tyre pressure monitors use pressure sensors to measure the pressure of the air inside the tyre. Industrial processes use pressure sensors to monitor gases or liquids in tanks and pipes so the microprocessor can keep them safe. Sensors send data into the computer system, so they are input devices. Output devices such as actuators act on the processed data.

Common mistakes: A tyre pressure monitor needs a pressure sensor, not a light sensor. The line should read from pressureSensor. An IF statement must be closed with ENDIF. ENDWHILE closes a WHILE loop, and there is no loop here.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

🖨 Print worksheet + answer key Add Pressure sensor to a class →

This module's key terms are also in a printable crossword (Modules 283–292) and word search (Modules 283–303).

Take this worksheet further — free with Cloodit

Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
Which data does a pressure sensor capture?
The amount of light falling on itThe force applied over an area by a gas, liquid or solid
Matches
A pressure sensor measures the temperature of the air in a tyre
↓
A pressure sensor measures pressure (force over an area), not temperature. A temperature sensor measures how hot or cold something is.
Applying
Meanings
Term
pressure sensor
Meaning
An input device that measures the force applied over an area by a gas, liquid or solid, e.g. in tyre pressure monitors, weather forecasting and pressure pads.
Practice
tyrePressure ← pressureSensor.READ()
Testing
Gaps
IF tyrePressure 30 THEN
Check Answer
Spots
1p ← READ(lightSensor)
2IF p < 30 THEN

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

The 'Sand Cat' badge — Precision Prowler, one of Cloodit's 106 collectible badges
Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy
Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games
Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print
Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Add to class →

Quick Questions

1. Which data does a pressure sensor capture?
A. The force applied over an area by a gas, liquid or solid ✓
B. The amount of light falling on it
A pressure sensor measures force over an area. Measuring light is the job of a light sensor.
2. A car's tyre pressure monitor warns the driver about a flat tyre. Which sensor does it use?
A. Humidity sensor
B. Pressure sensor ✓
Tyre pressure monitors use pressure sensors to measure the pressure of the air inside the tyre.
3. Which use of a pressure sensor is correct for weather forecasting?
A. Measuring air pressure to help predict changes in the weather ✓
B. Measuring the sound of thunder to work out the temperature
Weather stations use pressure sensors to measure air pressure. Falling or rising pressure helps forecasters predict the weather.
4. A pressure pad is placed on the floor and detects when someone steps on it. True or false: it uses a pressure sensor.
A. False
B. True ✓
A pressure pad senses the force of a person's weight pressing on it, so it uses a pressure sensor.
5. A factory must keep the pressure inside a chemical tank within safe limits. Which sensor is most suitable?
A. Pressure sensor ✓
B. Infra-red sensor
Industrial processes use pressure sensors to monitor gases or liquids in tanks and pipes so the microprocessor can keep them safe.

Match the Pairs

pressure sensor → An input device that measures the force applied over an area by a gas, liquid or solid
tyre pressure monitor → A pressure sensor inside a tyre that warns the driver when the air pressure is too low
A weather station uses a pressure sensor to measure air pressure for weather forecasting → IF airPressure < 1000 THEN OUTPUT "Storm likely"
A pressure pad sends a reading to the microprocessor when someone steps on it → IF padPressure > 0 THEN SoundAlarm()
A pressure sensor measures the temperature of the air in a tyre → A pressure sensor measures pressure (force over an area), not temperature. A temperature sensor measures how hot or cold something is.
Pressure sensors can only measure the pressure of gases → Pressure sensors can measure the force applied by a gas, a liquid or a solid, for example in industrial processes and pressure pads.

Key Term

pressure sensor
An input device that measures the force applied over an area by a gas, liquid or solid, e.g. in tyre pressure monitors, weather forecasting and pressure pads.

Fill in the Blanks

1. IF tyrePressure < 30 THEN OUTPUT "Low tyre pressure" ENDIF
Hint: Type the comparison operator that checks whether the tyre pressure is lower than the limit.
2. IF padPressure > 0 THEN OUTPUT "Person detected" ENDIF
Hint: Type the keyword that starts a selection, so the pressure pad reading can be tested.
3. // Weather station air pressure reading pressure ← READ(PressureSensor) OUTPUT pressure
Hint: Type the name of the sensor that captures the force over an area from the air.
4. pressure ← READ(PressureSensor) OUTPUT pressure
Hint: Type the pseudocode assignment symbol that stores the sensor reading in the variable.
5. IF pressure > maxPressure THEN OUTPUT "Open pressure valve" ENDIF
Hint: Type the keyword that closes the selection after the industrial process pressure check.

Spot the Error

Question 1
A p ← READ(lightSensor)
B IF p < 30 THEN
C OUTPUT "Tyre low"
D ENDIF
Line A — A tyre pressure monitor needs a pressure sensor, not a light sensor. The line should read from pressureSensor.
Question 2
A p ← READ(pressureSensor)
B IF p < 30 THEN
C OUTPUT "Tyre low"
D ENDWHILE
Line D — An IF statement must be closed with ENDIF. ENDWHILE closes a WHILE loop, and there is no loop here.
Question 3
A p ← READ(airPressureSensor)
B IF p < 1000 THEN
C OUTPUT Rain likely
D ENDIF
Line C — Text to be displayed must be in quotation marks. It should be OUTPUT "Rain likely".
Question 4
A pad ← READ(pressurePad)
B IF pad > 0
C OUTPUT "Step detected"
D ENDIF
Line B — An IF statement needs the keyword THEN after its condition. It should be IF pad > 0 THEN.
Question 5
A p ← READ(tankPressure)
B IF p > 200 THEN
C releaseValve ← CLOSED
D ENDIF
Line C — When the pressure in the tank is too high, the microprocessor should make the actuator OPEN the release valve to lower it. Closing it would let the pressure keep rising.

Student with a class code? Join your class →