Wireless Sensor Network

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Wireless Sensor Network

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Hardware Design Testing
Software / Firmware Design Testing
Documentation
  Team Members
Sensor Antenna Interface
Tiny OS Research
Microsoft Project Deliverables
Thomas Butler
Power Supply
Communications Simulation Research
Meeting Minutes Deliverables
Kelly Lancaster
Power Supply DC to DC Converter
Research
Meeting Minutes Deliverables
Michael Middleton
 
 Microcontroller Interface
Porting TinyOS Application Design
Webpage Design Deliverables
Leader Kennabec Walp
 
The Lazz
Dr. Georgios Lazarou Advisor
Jan Baranski Industrial Advisor
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Wireless Sensor Networks

• Consist of many small, reliable, and efficient
  remote sensors (motes)
• Communicate with other sensor modules over a
  self-configuring ad hoc network

Base Station
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Features

• TinyOS
• Unprecedented Communications and Processing
• 6 Mo. Battery Life
• 2-1.5V AA Batteries
• Self-Organizing Network
• Various Sensing Capabilities
• Light, Temperature, Barometric Pressure,
  Acceleration, Acoustic, Magnetic, etc.

University of California at Berkeley
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Objective

• To pursue a full understanding of the state of
  the art in WSN technology
• Enhance the state of the art in WSNs
• Spearhead WSN research at Mississippi State
  University
• To design a digital wireless communication system

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Prototype Redesign
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(No Transcript)
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Prototype Center Freq(VCO Tank 27nH)

• Inverse Relationship Observed

Medial Inductance of 19 nH to Provide 433.3 Mhz
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VCO Tuning

• VCO Tank Inductor affected the operating
  frequency

____
f 1 / (2pvLC)

• Initial 27 nH inductor produced center
  frequency of 406.90 MHz
• Adjusting L affects the center frequency

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VCO Tuning

• Inverse Relationship Observed

• Medial Inductance of 19 nH to Provide 433.3 Mhz

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Corrected VCO

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Hardware
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PCB Design Issues

• PCB Layout
• Trace Lengths
• Corners Edges
• CC1010
• .5mm pin pitch very difficult to work with.
• Must be careful not to induce parasitic
  capacitance with long, closely spaced traces.

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PCB Issues
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Size Reduction

• Current PCB is 3.00 X 2.75
• Our size goal is 3.00 X 2.00
• Will eliminate unused I/O pins and their
  respective components.
• 4 Layer Board Provides for more size efficient
  routing

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Package (Rev 01)
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PCB Design Issues
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Transmission Distance
d 300 ft.
Receive
Transmit

• Receiver Sensitivity -102 dBm
• Attenuation ((4pd)/?)2 2.749106
• Attenuation 10log(2.749106)30 94.4 dBm
• Ptrans Attenuation Prec,min 94.4-102 -7.6
  dBm
• PA_POW 0x07

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Sensor Interface

• External sensor module plugs into each mote.
• 20 Pin Connector
• 13 Digital I/O
• 3 Analog I/O
• 1 GND
• 1 PWR

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Software
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TinyOS

• Open Source Modular Runtime Environment
• Designed for Embedded Systems
• Concurrency-Intensive Applications
• Minimal Hardware Resources
• Ad hoc Networking
• Runtime Power Management

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OSI Protocol Stack

• System topology (routing and addressing)
• Multiple Access Strategies
• RF links need repeaters (handled within Tiny OS)

• Framing
• Error handling
• Link Control

NETWORK

• Handles physical access to transmission medium
• RSSI - Monitor the channel for activity

DATA LINK
PHYSICAL
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Communication System Block Diagram (TX/RX Chain)
FSK
XMT
hc(t) Channel Impulse Response
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Network

• Ad Hoc Network
• Connection method for wireless networks that
  requires no central routing
• Devices discover others within range to form a
  network
• Routing is distributed among the nodes
• Uses a shortest-path-first algorithm with a
  single destination node

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Medium Access Control

• Shared, broadcast medium (radio waves)
• MAC minimizes incidence of collisions
• CSMA-CA
• Carrier-Sense Multiple Access with Collision
  Avoidance
• Half duplex MAC protocol
• Implemented using RSSI within TinyOS

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Channel Coding

• Forward error correction
• Allows error detection and correction
• BCH
• Linear block coding method
• Outperforms all other block codes with same block
  length and code rate
• Currently simulating to find maximum coding gain
  for various code rates.

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Testing
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Design Constraints
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Prototype Spectrum
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PCB Spectrum
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Design Constraints
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Updated Cost
Design Constraint 35.00
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Design Constraints
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Size
2.75
3
10
3
2
10
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Design Constraints
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Summary

• Design a Wireless Sensor Network
• Improve performance via
• Channel Coding
• Efficiency

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Design II Goals

• Meet size constraint by reducing PCB size to 2 X
  3
• Transmission distance test
• Power test
• Efficiency test
• Channel code simulation testing

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Future Work

• Encryption
• CC1010 supports hardware encryption
• DES and DES3
• Can be simply inserted into block diagram
• Frequency Hopping
• CC1010 supports frequency hopping
• Smaller
• Size of a speck of dust (smart dust)

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Acknowledgements

• Dr. Georgios Lazarou
• Mr. Jan Baranski
• Dr. Joe Picone
• Jordan Goulder
• Our Fellow Students

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Questions

• ?

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Transmission Distance Prototype Vs. Final
Package
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Power Consumption Prototype Vs. Final Package
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PCB Layout
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Analysis of RF Circuit

• Minimum trace length required
• Calculation for power required to transmit 300ft.