Information and Communication Technology (0417) | Input devices and their uses

💻 IGCSE ICT Study Notes: Chapter 2.1 & 2.2 - Input Devices and Their Uses

Hello future ICT expert! This chapter is all about how we feed information into the computer. Think of input devices as the computer's senses—they allow it to see, hear, feel, and receive instructions from the outside world.
Mastering this section means you can easily compare devices and explain why one device is better suited for a specific task (like reading exam papers versus scanning groceries). Let's dive in!

2.1 General Input Devices and Their Uses

An Input Device takes data or instructions from the outside world and converts it into a digital format that the Central Processing Unit (CPU) can understand and process.

A. Text and Instruction Input Devices

1. Keyboard

Characteristics: The standard QWERTY layout. Sends signals to the CPU when a key is pressed.
Uses: Entering text, numbers, and commands (e.g., in a word processor).
Advantages (A): Fast for trained typists, easy to check data before input.
Disadvantages (D): Can be slow for non-typists (slow data entry), takes up desk space, risk of Repetitive Strain Injury (RSI).

2. Numeric Keypad

Characteristics: A small section containing only numbers and basic mathematical operators.
Uses: Ideal for systems requiring fast numeric data entry, such as Point of Sale (POS) terminals or when entering banking PINs.
A: Much faster than a full keyboard for numeric data entry.
D: Only suitable for numbers and limited functions.

B. Pointing and Selection Devices

These devices are used to control a cursor or pointer on the screen to select, drag, or open items.

3. Mouse (A Pointing Device)

Characteristics: Uses optical sensors or a ball to detect movement across a surface.
Uses: Navigating Graphical User Interfaces (GUIs), drawing, gaming.
A: Very quick selection and control, easy to learn.
D: Needs a flat surface, wires can clutter a desk, can cause RSI with prolonged use.

4. Joystick / Driving Wheel

Characteristics: Joysticks are lever-based controllers; driving wheels mimic steering wheels.
Uses: Primarily for gaming applications, especially flight simulators or racing games.
A: Provides a highly realistic and intuitive control experience for specific tasks.
D: Expensive, only useful for specific applications (gaming).

5. Remote Control

Characteristics: Uses infrared (IR) or radio frequency (RF) signals to control devices from a distance.
Uses: Controlling TVs, media players, or remote control systems in industry.
A: Allows control over long distances, highly portable.
D: Limited functionality, line-of-sight often required for IR remotes.

6. Touch Screen (Input Functionality)

Characteristics: Allows interaction by touching the display itself (using capacitance or resistance).
Uses: ATMs, smartphones, information kiosks, public ticket machines.
A: Very intuitive, eliminates the need for separate peripherals (mouse/keyboard).
D: Screen can get dirty or damaged, limited accuracy (difficult to select small items), causes *arm fatigue* for prolonged use.

7. Light Pen

Characteristics: A light-sensitive pointing device used to select objects or draw on a monitor screen.
Uses: Older CAD/CAM systems, light-sensitive drawing applications.
A: High precision for drawing directly onto the screen.
D: Only works with specific (older) screen types, requires you to hold your arm up, causing fatigue.

C. Image and Audio Input Devices

8. Scanner (Flatbed / Handheld)

Characteristics: Captures a physical image or document and converts it into a digital file (bitmap image).
Uses: Digitising old photos, converting documents into computer files.
A: High quality digital capture, preserves original documents.
D: Can be slow for high-resolution images, file sizes are very large.

9. Camera (Digital Still and Video)

Characteristics: Uses light sensors (like CCD or CMOS) to capture images and store them digitally.
Uses: Photography, security monitoring (CCTV), video conferencing, capturing evidence.
A: Instant results, images can be viewed and edited immediately.
D: Requires batteries/power source, image quality depends heavily on lighting conditions and sensor size.

10. Microphone

Characteristics: Captures sound waves and converts them into electrical signals, which are then digitised.
Uses: Voice recording, VoIP (Voice over Internet Protocol), voice recognition systems, virtual assistant interaction (Siri, Alexa).
A: Allows hands-free operation (e.g., voice commands), useful for people unable to type.
D: Requires quiet conditions for accurate capture, large sound files take up storage.

D. Environmental Input Devices

11. Sensors

Concept Alert! Sensors input physical data, which is Analogue. The computer needs this data to be converted into Digital form using an Analog-to-Digital Converter (ADC) before it can be processed or used to control systems.
Characteristics: Devices that measure physical quantities (temperature, pressure, light, humidity).
Uses: Monitoring and controlling systems (e.g., central heating, automated greenhouse, traffic lights).
A: More accurate and reliable than humans for continuous monitoring; can operate in hazardous environments.
D: Can generate huge amounts of data, needs frequent calibration, expensive setup.

✔ Key Takeaway (2.1): Every input device is a translator—it converts human actions (typing, clicking) or real-world physics (light, heat) into data the computer understands.

2.2 Direct Data Entry (DDE) and Associated Devices

Direct Data Entry (DDE) devices are designed to input data automatically, often bypassing manual typing. This process is generally faster and reduces human error (mistakes made during typing).

A. Reading and Recognition Systems

1. Bar Code Reader

Characteristics: Uses a laser to read the pattern of dark and light lines (a bar code).
Uses: Supermarkets (POS terminals), checking out library books, tracking inventory in warehouses.
Process: The reader scans the code, sends the number to the computer, the computer looks up the number in a database, and retrieves the price/product details.
A: Very fast and accurate data entry; allows for automatic stock control.
D: Bar codes can be damaged or misprinted, requiring manual input; limited information stored (only a code number).

2. QR Scanner (Quick Response Code)

Characteristics: Reads a two-dimensional matrix barcode.
Uses: Linking users directly to websites (marketing), contactless payments, storing complex data (like concert ticket details).
A: Can store much more data than a traditional bar code, easily readable by smartphones.
D: Requires a camera/scanner device, may need an internet connection to link to the destination website.

3. Optical Mark Recognition (OMR) / Reader

Analogy: Think of marking a multiple-choice exam paper.
Characteristics: Reads marked positions on forms using reflected light (it detects where a pen/pencil mark has been made).
Uses: Marking multiple-choice exams, school registers, survey forms.
A: Extremely fast processing of large batches of forms; very accurate if marks are clear.
D: Forms must be handled carefully; marks must be precisely placed (no scribbling!).

4. Optical Character Recognition (OCR) / Reader

Analogy: Converting a printed document into editable text.
Characteristics: Reads typed, printed, or sometimes handwritten text and converts it into a format that can be edited by software (like a word processor).
Uses: Converting paper records into digital documents, automated number plate recognition (ANPR) systems.
A: Reduces the need for manual re-typing, making digitisation quick.
D: Highly sensitive to font, handwriting quality, and document orientation; errors are frequent with poor quality text.

B. Security and Payment DDE Devices

5. Magnetic Stripe Reader

Characteristics: Reads data stored magnetically on the black stripe of credit/debit cards, security key cards, or loyalty cards.
Uses: Access control (hotel room keys), older credit card transactions.
A: Simple technology, cheap to manufacture.
D: Data can be easily damaged by magnets; data is unencrypted and easily stolen (card cloning).

6. Chip and PIN Reader

Characteristics: Reads encrypted data stored on the embedded microchip of a card, and requires the user to enter a Personal Identification Number (PIN).
Uses: Processing secure debit/credit card payments in retail.
A: Highly secure (data is encrypted); PIN confirms the user’s identity.
D: Slower than magnetic stripe reading; requires a dedicated terminal.

7. Radio Frequency Identification (RFID) Reader

Characteristics: Uses radio waves to read data stored on an RFID tag, which can be embedded in items or passports.
Uses: Tracking stock/inventory in shops and warehouses, electronic passports, automated toll collection.
A: Reads data without line-of-sight (can read multiple tags simultaneously); very fast tracking.
D: Can be intercepted (security risk); reader equipment is more expensive than bar code readers.

👉 Common Mistake to Avoid!

Do not confuse OCR and OMR.
OMR: Reads MARKs (circles/checkboxes) - good for multiple choice.
OCR: Reads CHARACTERs (letters/numbers) - good for text documents.

✔ Key Takeaway (2.2): Direct Data Entry devices are used when speed and accuracy are more important than manual control. They reduce human error because the data is read instantly, not typed.