Input can… [2]
- Provide Running software with instructions
- Be the data that must be processed
The camera
Input
- DSLR: Changeable lens, compact
- MP → the max resolution (total number of pixels that make up the image)
Scanner
Input device that scans images to a computer (barcodes, photos, 3D objects)
DPI
Dots per Inch: quality of scanned image
- Greater DPI = higher number of pixels; better image quality; larger file size
- Managed by software
Colour depth
Number of colours that can be represented by a pixel
Advantage of scanners
- Large documents stored in a single file
- Digital = does not take up physical office space
- Faster communication (emailing, QR codes)
- Scanning text to edit (OCR)
- Speedy checkout proces (POS)
Limitations of scanners
- Digital image copy depends on the quality of the physical one
- Scanning may take time
OCR
Optical Character Recognition
A type of software that can convert images of scanned text to editable text
Biometric input
Capture unique biological features of a person (fingerprint, iris) for identification
Advantages and limitations of biometrics
Advantages:
- More secure than passwords; cannot easily be copied
Limitations:
- Expensive to implement and maintain
- Requires additional hardware/software
Advantages and disadvantages of ATMs
Advantages:
- Banking anytime of the day
You are not limited to a single bank’s ATM in or outside the country
Disadvantages:
- Makes you prey to criminals
theives install “skimmers” in ATMs to captureyou details
RFID
Radio frequency idenitfication
- automatically recognises item
- Tags store data on cards which can be detected wirelessly
POS
- Scanners record stock; data is stored in a database with an allocated price for each item
- Cashier scans item you are buying
Advantages and liitations of POS
Advantages:
- Faster than typing prices
- Greater accuracy in prices
- Regulating stock
Disadvantages
- When the system is offline, it does not work
- Expensive to maintain
- Requires software
Practical example as sensors as an input device
- Detecting motion
- Vital signs of patients e.g. blood pressure, pulse etc.
- Monitoring/measuring weather data e.g. temperature, humidity, air pressure etc.
Advantage of sensors
Used in situations that are hazardous for humans
- Automatically captured, without human interaction and immediately
- No chance of human error in data capture
Accelerometer
Detects the way the device is being held or moved ie: playing car game while turning device as a ‘wheel’
The purpose of output
- Provide user with feedback
- Provides permanant or non-electronic copy of results of processing
- Allows transmission of data between devices
Touchscreens as an input AND output evice
- Provides intimate feedback to the user
- Interaction between user and computer
- Display content easily upated
- Text can be enlarged for the visually impared
Types of output [3]
- Visual: pop-ups, movies, hard/soft copies
- Sound: error messages, music
- Touch: vibration from joysticks, typing
Disadvantages of output
- non-permanant
- difficult to share
- eye strain
- chows electricity
Screen size, contrast ratio, aspect ratio, response time
Monitor
- Screen size: measured in inches
- Contrast ratio: number of shades between whitest white and blackest black
- Apect ratio: width and heigh of screen (4:3, 16:10)
- Response time: How quickly the monitor updates its pixels
Laser printers over inkjet printers
- More reliable (no nozzle to clog ink or dry out)
- Easier to maintain
- Cheaper to run
However, inkjets create more high quality photos
What makes devices work?
- Drivers
- Plug and play
