Wireless Localization System Using Propagation Timing

1
Wireless Localization System Using Propagation
Timing

• Brian Dake
• Brian Vaughan
• Sean Brennan

2
Basics

• Localization using propagation timing
• Location tracked in real time
• Can be used to control servos for tracking
• Spotlights, cameras, laser pointer, etc

3
Function

• 1 mobile mote
• 3 stationary motes
• Mote communication established through radio
  frequencies
• Localization calculated using propagation delay
  of ultrasound wave
• Servo motors follow the mobile mote in real time

4
Design

• Motes from Crossbow

5
Design

• Ultrasound TX/RX added to motes
• Mobile mote incorporates ultrasound TX
• Stationary mote incorporates ultrasound RX
• TinyOS from Berkeley available online to program
  motes

6
Implementation

• Mobile mote sends out radio and ultrasound
  signals at the same time

Mobile Mote
Stationary Mote
7
Implementation

• Stationary mote measures time difference between
  radio and ultrasound pulse
• Distance is calculated
• Position is found using multiple stationary motes
• Instructions given to servos for movement based
  on real time position

8
Problems

• Integrating ultrasound devices
• We can build our own motes using circuit diagrams
  from the MIT Cricket project
• Just use radio strength data (less accurate)
• Time delay in processing location
• Might be easier to implement using UHF RFID Radar

9
Mini-Project

• Implement the mote system using two motes
• Ultrasound and radio communication working

10
Questions?