Input Devices (Cambridge International IGCSE ICT)
Exam board Cambridge International · IGCSEUpdated 2024-05-21
Spec point —
2.1.1
Input Devices
What is an Input Device?
- Input devices are hardware components that **allow users to interact **with a computer system
- They enable the user to** input data or commands into the system**, which the computer then processes to produce an output
Types of input devices
| Input device | Advantages | Disadvantages |
|---|---|---|
| Keyboard (Entering data into a computer) | - Easy method of entering data - Very common | - Repetitive strain injury - Slow to enter data compared to direct data entry |
| Numeric Keypad (ATMs, chip and PIN devices) | - Fast - Easy to use | - Size of buttons can impede some users - Button layouts not always the same |
| Pointing Devices (Mouse) | - Intuitive and precise control - Fast to make on-screen choices | - RSI (strain on wrist) - Requires flat surface - People with disabilities can find them difficult to use |
| Remote Control (TV, hi-fi remotes) | - Easy to use - Can control from a distance | - May require line-of-sight - Easily lost - Needs regular battery replacements |
| Pointing Devices (Joystick/Driving Wheel) | - Enhances gameplay/simulation experience - Improve realism - Accurate | - Expensive - Limited use outside of gaming and simulators |
| Touchscreen (Smart phones & tablets) | - Intuitive - No need for a separate pointing device - Easy to keep clean | - Screens can get dirty - Easily scratched - Less precise than a mouse |
| Scanner (Convert paper documents to electronic) | - Accurate reproduction - Easy to share and store - Combined with barcodes becomes a DDE | - Quality depends on resolution - High quality means can be slow |
| Digital camera (Taking photos/videos) | - Vast amounts can be captured - No developing - Easy to share | - Storage compression can lead to a loss in quality - Need to be tech-savvy to use effectively |
| Microphone (Input speech, sensor to pick up sounds) | - Hands-free input - Can be used for voice recognition - Fast | - Variable quality - Verbal inputs can be inaccurate - Need to remember key words/phrases |
| Analogue sensors (Measure environmental data e.g. temperature, light, sound, humidity etc.) | - Generally accurate - Provides real-time information - Automatic - Can collect data from places where they may be threat to human life | - May require calibration - Data must be converted to digital data (ADC) - Data may need to be checked for accuracy |
| Light pen (Select/write on screen) | - Accuracy for fine detail - Small & lightweight - Easy to use | - Lag - Only work on certain types of screen - Dated technology |
Worked Example A house contains a microprocessor-controlled central heating system.
Identify two input devices that would be used in this system.
[2]
Answer
Two from:
- Keypad
- Temperature sensor
- Override switch for timing
- Touch screen
- Remote control//smartphone//tablet
Direct Data Entry
Spec point —
2.2.1
What is a direct data entry device?
- A direct data entry device is a device capable of inputting data into a computer with little/no human interaction
- Data collection and transfer is completed automatically
Types of direct data entry devices
| Direct data entry device | Advantages | Disadvantages |
|---|---|---|
| Magnetic stripe reader (Debit/credit cards) | - Fast - Simple to use - Secure (unreadable) | - Magnetic stripes can get damaged and become unreadable - Reader must be in close contact |
| Chip and PIN reader | - Secure - Reduced fraud risk | - Requires PIN input - Potential for skimming - High payment limits an issue for stolen cards |
| RFID reader (read only) (Contactless payment) | - Fast transaction (no pin) - Data wirelessly transferred securely - Retailers don't have to access customer credit/debit information | - Transaction limit is smaller - RFID signals can be read/intercepted |
| RFID reader (Security tags on clothes, location tracking ) | - Very fast - Data can be sent both ways - Bulk detection | - Radio waves can be blocked/jammed - Tag collisions - Possible to hack |
| Optical Mark Recognition (OMR, read marks on exam paper in pen/pencil) | - Fast processing - Reduced human error | - Limited to specific forms - Cannot read handwriting - Form must be completed accurately |
| Optical Character Recognition (OCR, text to digital data) | - Fast data entry - Accurate and less error prone | - Can struggle with complex layouts - Font dependent - Not always 100% accurate - Expensive |
| Barcode reader (reads barcode labels) | - Fast and accurate - Low cost - Allows for automatic stock control - Tried & trusted | - Requires line-of-sight - Barcodes are easily damaged - Barcodes can be swapped/altered by consumers |
| QR scanner (QR codes) | - Can store more data than barcodes - Versatile uses - Easy to read - Can be encrypted | - QR codes can store malicious code - Different QR code formats |
Worked Example For each of the following uses of data capture, name one appropriate direct data entry device. The devices must be different in each case
a. Contactless credit cards [1]
Final answer: Radio Frequency Identification/RFID reader [1]
b. Multiple choice answers in an examination paper [1]
Final answer: Optical Mark Reader/OMR [1]
c. To scan items at a computerised till [1]
Final answer: Bar Code reader/scanner [1]
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