4 Flashcards
(41 cards)
Input devices
transfer data from the source in the outside world to the computer
Examples include:
Keyboards
Mice
Digital cameras
Microphones
Types of Touchscreens
Resistive
Capacitive
Infra-red
Resistive touchscreens
Resistive touchscreens are made up of a layer of conductive polyester and a layer of conductive glass
- your fingers make those 2 layers touch
Capacitive touchscreens
Capacitive touchscreens are made up of glass layers
-When the screen is touched by a finger, there is a change in the electric field at that position. That position is then calculated by a microprocessor
-can be touched in more than one place at a time
Infra-red touchscreens
LEDs shine infra-red light across the screen from the edges and the infra-red rays form a grid across the screen
-When the screen is touched by a finger, the infra-red beam is interrupted
advantages and disadvantages of
-Capacitive screen have a smooth surface
-They are very easy to press
-They are highly accurate
-Capacitive screens don’t work if the
user is wearing gloves
Barcode readers
UPC-A systems:
This uses long guard bars to show the start and end of the barcode
Left hand codes- odd number of black bars.
Right hand codes- even number
Digital cameras
Digital cameras focus light onto a CCD sensor
3D scanners
3D scanners use a laser to
scan across an object
2D Scanners
These are used to convert documents or photographs into a digital format.
Examples:
Multi-function printers
Photocopiers
They can contain:
Describe how barcodes are used within supermarkets today.
Each product has a barcode located on it.
The barcode is scanned by a handheld scanner / at the checkout.
The computer processes the barcode to find its barcode/ID number.
The item is looked up to find the product name and price.
The stock in the shop is automatically updated.
Give two other applications of barcodes.
Uses may include:
Library books and library cards.
Tracking luggage at airports.
Tracking packages.
Why use barcodes?
- It is faster to scan products than enter a price in to a till
- no stock control necessary
- Barcodes reveal a number that identifies each product. This allows a shop to determine how many items are sold
-Saves the need for shop workers to manually check stock levels - Prices can be changed without needing to update the price on each product
QR codes
QR codes are 2D barcodes and can be read by smartphones or tablets
They contain:
Links to websites or
Information
Uses of QR codes in society
Tracking packages
Restaurant menus
Mobile concert tickets
Tourist info
uses for 3D sanners
Checking parts for faults.
Tomography
MRI scans.
Medicine
Gas sensor
Detecting CO2 levels
Detecting O2 levels
Detecting CO (carbon monoxide) levels in a home alarm
pH sensor
Detecting the acidity of soil
Detecting the acidity of liquids
Light sensor
Automatic turning on of car lights
Turning on street lights
Level sensor
Finding how much fuel is left in a car
Finding the amount of grain stored
Pressure sensor
Detecting if someone is standing on a special mat at an entrance
Detecting how much air is in a car tyre
Infra-red sensor
Security lights
Detecting movement in alarm systems
Moisture sensor
control or monitor the dampness of soil in a greenhouse
measure water content in a lawn for an automatic watering system
Humidity sensor
monitor the humidity in the air of a greenhouse
control a dehumidifier in a home