Choose an input device
Match keyboards, cameras, microphones, pointing devices, scanners and touchscreens to the data they capture.
This sequence follows Cambridge IGCSE Computer Science 0478, 2026–2028 syllabus Version 6. It covers subject content sections 3.1–3.3 only. The separately published 2029–2031 syllabus is not mapped here. Practice is original, self-checked and does not award an official Cambridge grade. Full timed papers and human subject-teacher review remain outstanding.
Before you begin
- No programming language is required. Be comfortable with place value and multiplication; each lesson introduces the computer-science notation it uses.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What does an input device do?
What you will learn
- Define an input device
- Identify what common input devices capture
- Select an input device for a context
Input devices send data into the computer
An input device captures or enters data for processing. A keyboard enters text; a microphone captures sound; a digital camera captures images; and an optical mouse detects movement.
Apply and check the rule
Barcode and QR-code scanners read machine-readable codes. A touchscreen can capture touch input as well as display output. A 2D scanner captures a flat image, while a 3D scanner captures shape or surface information.
Pause and explain
Which device is most suitable for entering typed words?
Worked example
A library needs to record a printed book's barcode at checkout. Which input device is suitable?
Show the worked solution
- The system needs to capture a printed code.
- A barcode scanner reads that code as input data.
- The software can then use the captured identifier.
Answer A barcode scanner, because it reads the printed barcode and enters its code into the system.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Choose an input device to capture a spoken student's answer.
Give me a hint
Identify the form of data being captured.
Compare my reasoning
- The answer is spoken sound.
- A microphone captures sound for processing.
Microphone
Look for these in your work
- Sound identified
- Device selected
A museum digitises both a flat drawing and a small sculpture. Which scanner types could capture each?
Give me a hint
Distinguish a flat image from a three-dimensional shape.
Compare my reasoning
- A 2D scanner captures the flat drawing.
- A 3D scanner captures the sculpture's shape.
A 2D scanner for the drawing and a 3D scanner for the sculpture.
Look for these in your work
- Flat image matched
- 3D object matched
A tablet uses its screen to show a map and accept finger taps. Explain why the touchscreen has both input and output roles.
Give me a hint
Separate displayed information from captured touches.
Compare my reasoning
- The screen displays the map as output.
- The touch layer captures the user's taps as input.
- The same physical screen assembly can perform both roles.
It outputs the map and inputs the user's touch coordinates; a touchscreen combines display and touch sensing.
Look for these in your work
- Display role
- Touch role
- Both roles distinguished
Common mistakes
- Calling a display screen an input device when no touch capability is specified
- Confusing a QR-code scanner with a barcode scanner's captured content
What can you explain now?
Which device captures sound as input?
Compare with the explanation
Microphone
A microphone converts sound into data that a computer can process.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Name one device for each: text, sound, barcode and three-dimensional shape input.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.