Input Devices
How does data get into a computer, and which device suits which job?
- Define an input device and give the general input–process–output model
- Classify input devices by the type of data they capture
- Choose the right input device for a given real-world task
Overview
An input device is any hardware that sends data or instructions into a computer. Every computing task starts with input — typing an assignment, tapping a screen, swiping a card at the supermarket, or scanning a fingerprint at a bank. The input–process–output (IPO) model describes the flow: data goes in, the CPU processes it, and results come out.
Input–process–output
Input devices capture raw data and convert it into the digital signals (1s and 0s) the computer understands. The processor works on that data, and output devices present the result. Storage sits alongside, keeping data for later.
Categories of input device
Grouping devices by what they capture makes them easy to remember.
Six categories with examples:
- Keying devices: Keyboard, numeric keypad, virtual on-screen keyboard — enter text and numbers.
- Pointing devices: Mouse, trackpad, trackball, joystick, stylus, touchscreen — select and move on screen.
- Scanning & reading devices: Flatbed scanner, barcode/QR reader, OMR (mark sheets), OCR (printed text), MICR (bank cheques), magnetic-stripe and chip card readers.
- Audio & video capture: Microphone, webcam, digital camera, video camera — capture sound and images.
- Biometric devices: Fingerprint scanner, face and iris recognition, voice recognition — identify a person.
- Sensors: Temperature, light, motion, GPS, gyroscope and touch sensors — capture data from the physical world in embedded and IoT systems.
Choosing the right device
Match the device to the data and the setting. A supermarket in Port Moresby uses a barcode scanner because it is far faster and more accurate than typing product codes. A school marking multiple-choice exams uses OMR. A bank uses biometrics because a fingerprint cannot be borrowed like a PIN.
Accessibility and health
Adapted input devices — large-key keyboards, head pointers, switch access, speech-to-text — let people with disabilities use computers. Poorly set-up keyboards and mice cause repetitive strain injury, so posture and wrist support matter (see Week 9 revision on safe practice).
Match the device to the job
- Copy a two-column table: Task | Best input device (+ reason).
- Tasks: (1) Marking 400 multiple-choice answer sheets; (2) Checking out groceries at a store; (3) Recording a school radio interview; (4) Signing in staff without ID cards; (5) Digitising an old printed textbook page; (6) Measuring classroom temperature every minute.
- Justify each choice in one sentence, then compare answers with another pair.
- Define an input device.
Reveal answer
Any hardware that sends data or instructions into a computer for processing.
- Give two examples of pointing devices.
Reveal answer
Mouse and touchscreen (also trackpad, trackball, stylus, joystick).
- What is the difference between OMR and OCR?
Reveal answer
OMR reads the position of pencil marks; OCR recognises the shapes of printed or written characters as text.
- Why do banks use biometric input?
Reveal answer
A fingerprint or face is unique to the person and cannot be shared, lost or guessed like a PIN.
- Name one sensor used as an input device and what it captures.
Reveal answer
A temperature sensor captures heat levels as data (also GPS, light, motion).
Count every input device on your phone (touchscreen, microphone, camera, fingerprint, GPS, gyroscope…) and list what each one captures.