3.2.1 | INPUT DEVICES

Topics from the Cambridge IGCSE (9-1) Computer Science 0984 syllabus 2023 - 2025.

OBJECTIVES
3.2.1 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

ALSO IN THIS TOPIC
3.1.1 COMPUTER ARCHITECTURE 
3.1.2 COMPUTER ARCHITECTURE 
​3.1.3 COMPUTER ARCHITECTURE 
​3.1.4 COMPUTER ARCHITECTURE 
3.1.5 COMPUTER ARCHITECTURE 
YOU ARE HERE | ​3.2.1 INPUT AND OUTPUT DEVICES 
3.2.2 INPUT AND OUTPUT DEVICES 
3.2.3 INPUT AND OUTPUT DEVICES
3.3 DATA STORAGE 
3.4 NETWORK HARDWARE 
REVISION CARDS
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES
TOPIC 1 TEACHER RESOURCES (CIE)

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3.2.1 INPUT AND OUTPUT DEVICES

An input device is a piece of hardware that is used to transfer data from the user or another device into a computer or other electronic device. This can include receiving visual, auditory, or tactile information from the user. Input devices are required to allow the user to interact with the computer or device and provide it with information.

Examples of input devices include:

Keyboard: A keyboard is a device that allows the user to input text and commands into a computer. They can be used for typing documents, programming, and gaming.

Mouse: A mouse is a device that allows the user to point, click and move the cursor on a computer screen.
Optical mouse: An optical mouse uses a light-emitting diode (LED) and a photodetector to detect movement on a surface. It is an alternative to the traditional mechanical mouse that uses a ball.

Touchscreen: A touchscreen is a display screen that can detect the presence and location of a touch within the screen area.

Scanner: A scanner is a device that converts a printed image or document into a digital format.

Microphone: A microphone is a device that converts sound waves into an electrical current, used for recording or transmitting sound. They are used in music production, podcasting, videography, and other sound-related fields.

Digital camera: A digital camera is a device that captures images in digital format. They can be used for personal, professional and commercial photography, videography, and other visual art.

Barcode scanner: A barcode scanner is a device that uses a laser or camera to read the data encoded in a barcode. It can be used in a variety of applications such as inventory management, point-of-sale systems, and tracking packages.

Game controller: A game controller is a device that allows the user to interact with a game, typically through buttons and joysticks.

Biometric devices: Biometric devices such as fingerprint scanner, iris scanner, and facial recognition are used to identify a user by their unique physical characteristics.

QR code scanner: A QR code scanner is a device or software that can read and interpret the data encoded in a QR code. They are commonly used for quick access to websites, contact information, and other types of data.

Touch screen: A touch screen is a display screen that can detect the presence and location of a touch within the screen area. There are different types of touch screen technology including resistive, capacitive, and infra-red. They are commonly used in smartphones, tablets, and other portable electronic devices.

• Resistive touch screens use a layer of resistive material, such as plastic, that is coated with a thin layer of metal. When an object, such as a finger, comes into contact with the screen, it applies pressure to the resistive layer, causing it to make contact with the metal layer beneath. This creates a change in electrical current, which the touch screen controller uses to determine the location of the touch.
• Capacitive touch screens use a layer of conductive material, such as glass, which is coated with a thin layer of metal. When an object, such as a finger, comes into contact with the screen, it changes the electrical field of the conductive layer, which the touch screen controller uses to determine the location of the touch.
• Infrared touch screens use infrared light-emitting diodes and photo transistors to create a grid of infrared light beams across the screen. When an object, such as a finger, comes into contact with the screen, it interrupts the infrared beams, which the touch screen controller uses to determine the location of the touch.

Two-dimensional (2D) scanner: A 2D scanner is a device that captures the image of a flat object and converts it into a digital format. They are commonly used for scanning documents, photographs, and other flat objects.
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Three-dimensional (3D) scanner: A 3D scanner is a device that captures the shape and surface of a physical object and converts it into a digital 3D model. They are commonly used in manufacturing, engineering, and other fields where accurate 3D models are needed.
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These devices are required to allow the computer or device to receive and interpret input from the user, which enables the user to interact with the device and perform tasks such as typing, clicking, moving the cursor, taking pictures, recording sound, scanning documents and so on.

1. Explain the process of how a barcode scanner works and the different types of barcode technology available. [6]
2. Explain the differences between resistive, capacitive, and infra-red touch screens, and give examples of when each technology is commonly used. [6]
3. ​QR codes are often used in restaurants, give a purpose for this and list 2 advantages and 2 disadvantages. [6]

ALSO IN THIS TOPIC

3.1.1 COMPUTER ARCHITECTURE | The role of the CPU
3.1.2 COMPUTER ARCHITECTURE | Components of the CPU
3.1.3 COMPUTER ARCHITECTURE | Core's, Cache and Clock speed
3.1.4 COMPUTER ARCHITECTURE(CIE) | The Instruction Set
3.1.5 COMPUTER ARCHITECTURE | Embedded Systems
3.2.1 INPUT AND OUTPUT DEVICES | Input Devices
3.2.2 INPUT AND OUTPUT DEVICES | Output Devices
3.2.3 INPUT AND OUTPUT DEVICES | Sensors
3.3 DATA STORAGE | Primary, Secondary, Virtual and Cloud storage
3.4 NETWORK HARDWARE | Networks, Components and Protocols
REVISION CARDS | Flip cards to help test yourself
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES