Key areas of pervasive computing
- context aware#
- wearable computing
- augmented reality
- wireless sensor network
- Created by: Erhuvwu akpobaro
- Created on: 25-04-14 01:27
Wireless sensor network
- is a system composed of multiple wireless sensors
- it is more or less a stratergy than key area
- difficult to implement
Types of pervasive data
- location
- temperature
- gases
- position
- sound
- pressure
- light
Pervasive Hawrdware
Sensors
- Sensors gather data
Interface
- it helps to visualise the state of the data
Micro-controller board
- this is the main connection between the sensors and the interfaces
- can be embedded due to their size
Buses
- A bus is a physical connection , which can be shared by multiple hardware componets , in order to communicate with one another.
- another purpose of buses is to reduce the number of pathways needed for communication between the componets by carrying out all communications over a single data channel.
Sesnors
A sensor is a converter that measures a physical quantity and converts into signal which is by a instrument
GPS
- Stands for Global Positioning system
- works by using a triangulation of satelite signals
- genrally limited to outside due to the need for satelite connection
Infrared
Electromagnetic Radiation
used for old phones , night vision
Ultrasound
- uses soundwaves
- much like sonar and radar
- needs an emitter to fully work
Radio Frequency
- uses radio waves
- can get interupted easily
- enables wireless communication between devices
Temperature sensor
it is used to calculate the temperature of a surface or an area
there are to types of tempreture sensors , these are :
- contact
- non-contact
Temperature sensor part 2
Contact
- Thermocouples
- Thermoresistor
Non-contact
- Thermal radiation
Pressure Sensor
used for measuring pressure of fluids
example types of pressure sesnors consist of vaccum and guage .
Vaccum
measures pressure below ambient pressure
Guage
measures atmospheric pressure
Accelerommeter
It is able to clalculate change in force
used to detect movement
Serial Connection and processing
Connections
there are many different connection and componets
the device must match the format of the device connecting to
Serial
is a method of sending data between devices
data is transfered one bit at a time
There are two forms of serial data transfer
Serial Communication
It is normally bit - bit
Used in networks as well as long distance communication
Serial cable are easier and therefore cheaper
less cables
data is sent yo each clock tick
and example of this is a USB
Serial Bus
A bus is used to transfer data inside a device between key componets
data travels at 1 bit at a time
Input and Expansion
Analouge input
it is a continious wave which is varied by a thrid party parameter .
change in voltage depicts the alteration of a third party parameter.
Examples
- potentiometer
- accelerometer
- temperature sensor
Digital input
Continiuous bit-stream with a data range 0 and 1
constantly sends a value to the input
RFID / NFC
RFID
- wireless
- non-contact
It uses Radio frequnecy magnetic fields to transfer data
there are two typed of RFID tags they are :
- Powered
- Non-powered
they are also made of two componets which are :
- Reciever and tag
Non-powered RFID
- doesnt have a local powere source
- the magnetic fields of the reader powers the device and transfer data
- data is usually a single string or integer
Powered RFID
- Contains a bttery which allows the device to transmit at a longer range
- Means the overall device is large and heavier
The purpose of RFID example
- RFID are execellent ways to track items or objects with implemented RFID tags
- used for identifcation
NFC
- IT is based of RFID technology
- fundamentals are the same
- two way communication is needed
PROS
- can detect users through unqiue tag codes
- passive tags do not require a portable power source
CONS
- hackers can scan tags and get data
- it cant pass large volumes of data
- needs a larger scanning system
GND(-) pin - Ground pin
- It is used to complete the circuit
- the thread in a ground pin is not insulated
- the thread in a ground pin is connected to a end pin , it must not touch any thread connected to a different pin
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