Introduction to Peripheral Devices
Welcome to one of the most practical parts of your ICT course! Have you ever wondered how your computer actually "hears" you, or how a flat-screen printer turns a digital file into a solid 3D object? That is all thanks to peripheral devices.
A peripheral is any hardware device that connects to your computer to provide input (sending data in) or output (getting data out). Think of the computer as the "brain" and the peripherals as the "senses" (eyes, ears, hands) and the "voice."
Input Devices: Sending Data to the Brain
Input devices allow us to interact with a computer system. We use different devices depending on the type of data we want to enter.
1. Manual Input Devices
These require a human to physically move or press something:
Keyboard: The most common way to enter text and commands.
Mouse: A pointing device used to select icons and navigate the screen.
Tracker Ball: Similar to a mouse, but the ball stays on top. You move the ball with your fingers. Great for people with limited wrist movement (accessibility) or for use in small spaces.
Joystick: Often used for gaming or controlling machinery.
Graphics Tablet: A flat pad used with a stylus. It’s like drawing on paper but the image appears on the screen. Artists love these because they are much more precise than a mouse.
Touch Screen: You use your fingers to interact directly with the screen. Note: These are unique because they act as both an input and an output device!
2. Capturing Images and Sound
Scanner: Converts physical paper documents into digital images.
Digital Camera: Captures still images and stores them digitally.
Webcam: A camera connected to a computer, usually for video calling or streaming.
Microphone: Captures sound waves and converts them into digital audio files.
3. Specialist and Automated Input
Sometimes we need to enter data quickly or automatically without typing:
OMR (Optical Mark Recognition): Reads marks made by a pen or pencil (like on a multiple-choice exam paper or a lottery ticket).
OCR (Optical Character Recognition): This software works with a scanner to turn a picture of text into a document you can actually edit in a word processor.
Bar Code Scanner: Uses light to read the black-and-white lines on products. You'll see these at every supermarket checkout!
Biometric Scanner: Recognises human physical features, like fingerprints or facial patterns. These are used for high-level security.
Magnetic Stripe Reader: Reads the black stripe on the back of old credit cards or membership cards.
Chip and PIN: The modern way to pay. The device reads the "chip" on your bank card, and you enter a PIN (Personal Identification Number) for security.
Sensor: Automatically detects physical changes in the environment, such as temperature, light, or pressure. These are used in "control systems" (like a thermostat turning on the heating).
Key Takeaway: Choose the input device that fits the task. You wouldn't use a keyboard to enter a fingerprint, and you wouldn't use a barcode scanner to write an essay!
Output Devices: Showing the Results
Output devices take the processed data from the computer and present it to the user in a way we can understand.
1. Visual Output
Monitor: The most common output device. When looking at monitors, we care about:
- Screen Size: Measured diagonally in inches.
- Resolution: The number of pixels on the screen (e.g., \(1920 \times 1080\)). A higher resolution means a sharper, clearer image.
Data Projector: Beams the computer screen onto a wall or large screen. Best for presentations to large groups.
2. Printers and Plotters
How we get "hard copies" (physical versions) of our work:
Inkjet Printer: Uses liquid ink. Best for home use and high-quality photo printing.
Laser Printer: Uses dry toner. Very fast and cheap per page. Best for schools and offices that need to print many pages quickly.
3D Printer: Creates physical, three-dimensional objects by "printing" layer upon layer of material (like plastic). Used for making prototypes or custom parts.
Plotter: A specialist printer that uses pens to draw huge, high-quality technical drawings, like blueprints for architects or giant maps.
3. Sound and Action
Speakers: Convert digital signals into sound.
Control Device: These are outputs that do something in the real world. For example, a computer might send a signal to a motor to open a gate, a heater to warm a room, or a light to turn on.
Quick Review: Laser printers are for speed; Inkjets are for photos; Plotters are for giant drawings.
Choosing the Right Device: Context and Accessibility
In your exam, you might be asked to suggest a device for a specific person or situation. Here are some things to keep in mind:
Accessibility (Meeting Special Needs)
If a user has a physical disability, standard peripherals might not work. We can use:
- Tracker balls for people who find it hard to move their whole arm.
- Microphones with voice-to-text software for people who cannot type.
- Large-key keyboards for people with visual impairments.
Real-World Scenarios
Scenario 1: A supermarket wants to update prices quickly.
Solution: Use Bar Code Scanners to identify items and Monitors to show the price to the customer.
Scenario 2: An architect needs to print a large-scale plan of a new stadium.
Solution: A Plotter, because a standard printer is too small and not precise enough for giant blueprints.
Did you know? The term "Convergence" (which you learned in Topic 1.1) applies here too! Your smartphone has a microphone, speaker, camera, and touch screen all in one tiny device. It's a "multifunctional" powerhouse!
Chapter Summary
Input: Getting data into the system (Keyboard, Mouse, Sensors, OMR, OCR, Biometrics).
Output: Getting information out of the system (Monitors, Printers, Speakers, Control Devices).
Resolution: Higher resolution = more detail.
Suitability: Always pick the device based on the user's needs and the environment (e.g., use a laser printer for a busy office, not an inkjet).