Edexcel 1CP2 · Topic 3 · 3.2b

Input & Output
Devices

Keyboards · Mice · Scanners · Monitors · Printers · Actuators · Sensors

CSZoneEdexcel GCSE Computer Science 1CP2

Input Devices

Getting Data into the Computer

Keyboard: text and command input; most common; keys generate character codes

Mouse / Touchpad: pointing device; detects movement and click inputs

Touchscreen: input and output combined; capacitive or resistive; phones, tablets

Scanner: captures images of physical documents — flatbed or handheld

Microphone: captures audio; used for voice recognition (e.g. virtual assistants)

Barcode reader / QR scanner: reads encoded data from patterns of lines or squares

Output Devices

Presenting Results from the Computer

Monitor / Screen: displays visual output; measured in pixels (resolution) and refresh rate (Hz)

Printer: produces hard copy — inkjet (small volume, colour), laser (fast, high volume), 3D (additive manufacturing)

Speaker: audio output; used in entertainment, accessibility, alerts

Actuator: a motor or servo controlled by computer output — used in robotics and control systems (e.g. opening a valve, moving a robotic arm)

Sensors in Systems

Collecting Real-world Data

Sensors are specialised input devices that detect physical quantities and convert them to digital signals for the computer to process. Used in embedded systems and control applications.

Temperature sensor → thermostat / weather stations

Light sensor (LDR) → automatic street lights, cameras

Pressure sensor → intruder alarms, medical monitors

Infrared / motion sensor → security systems, automated doors

Exam Practice

Have a go at this question

Edexcel-style question

A greenhouse uses a computer to control temperature automatically. Identify one suitable input device and one suitable output device, and explain their roles.

4 marks

Input: temperature sensor — detects the current temperature and sends it to the computer [1+1]. Output: actuator (e.g. heater motor) — the computer sends a signal to switch the heater on/off to maintain the desired temperature [1+1].

Key Takeaways

What to Remember

Input: keyboard, mouse, touchscreen, scanner, microphone, barcode reader, sensors

Output: monitor, printer, speaker, actuator (motor/servo)

Sensors convert physical quantities to digital signals — used in control systems

Actuators carry out physical actions based on computer outputs — robotics, automation