Input and Output Devices

2026 Syllabus Objectives

By the end of this topic, you should be able to:

  1. Understand what is meant by an input device and why it is required, including: barcode scanner, digital camera, keyboard, microphone, optical mouse, QR code scanner, touch screen (resistive, capacitive and infra-red), two-dimensional (2D) and three-dimensional (3D) scanners

  2. Understand what is meant by an output device and why it is required, including: actuator, digital light processing (DLP) projector, inkjet printer, laser printer, light emitting diode (LED) screen, liquid crystal display (LCD) projector, liquid crystal display (LCD) screen, speaker, 3D printer

  3. Understand what is meant by a sensor and the purposes of sensors, identify the type of data captured by each sensor and understand when each sensor would be used, including selecting the most suitable sensor for a given context (acoustic, accelerometer, flow, gas, humidity, infra-red, level, light, magnetic field, moisture, pH, pressure, proximity, temperature)


What is an Input Device?

An input device is a piece of hardware (physical equipment) that allows users to interact with a computer system. It lets you send data or commands into the computer, which the computer then processes to produce results.

Think of it like this: if a computer is like a chef, input devices are the ways you tell the chef what to cook and give them the ingredients.

Why Input Devices are Required

Without input devices, we couldn't communicate with computers. We need them to:

  • Enter information and data into the system
  • Give commands to the computer
  • Control what the computer does
  • Capture information from the real world (like photos or sound)

Types of Input Devices

Barcode Scanner

What it does: Reads barcodes (those black and white stripes you see on products) to capture product information.

Where it's used:

  • Supermarkets (at the checkout)
  • Warehouses (tracking stock)
  • Libraries (checking out books)

Why it's used: It quickly and accurately retrieves product details. This makes checking out faster and helps keep track of stock levels. Scanning is much faster and more accurate than typing in product codes manually.

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