03-01-2013, 04:21 PM
Wireless Sensors and Wireless Sensor Networks (WSN)
1Wireless Sensors.ppt (Size: 48 KB / Downloads: 63)
Advantages of Wireless Sensors
Much cheaper to deploy than wired sensors
Sensor nodes can be added or removed easily
Node location can be changed without rewiring
Can be configured into different network topologies
Star, Mesh, etc.
Microcontroller
Contains CPU, Memory and Peripherals on same chip
Typically 8-bit or 16-bit
Operate at less than 20MHz
Memory less than 128kB
Low power consumption to ensure long run times
Radio Transceiver
Typically operate in the ISM bands
Use various modulation techniques
QPSK, BFSK, GFSK
Low Output Power 0dBm or 1mw
Low Range around 10-300 feet
Applications
HVAC Systems
Home Automation
Structural Monitoring ( Bridges, Buildings)
Area Monitoring
Monitoring condition of Machinery
Agricultural
IEEE 802.15.4
Part of the 802.15 wireless PAN standard
Specifies the PHY and MAC layers
Created for low data rate and multi-month or multi-year battery life
Targeted Applications
Sensors
Interactive Toys
Smart Badges
Remote Controls
Home Automation
Zigbee Device Classes
Zigbee Coordinator (ZC)
Most capable deviece
Forms the root of the network tree and bridge to other networks
Acts as repository for security keys
Zigbee Router (ZR)
Can pass data from one device to another
Zigbee End Device (ZED)
Contains just enough functionality to talk to its parent node either ZC or ZR