Wireless Localization Wireless Localization System Using System Using

Propagation TimingPropagation Timing

Brian DakeBrian Dake

Brian VaughanBrian Vaughan

Sean BrennanSean Brennan

BasicsBasics

Localization using propagation timingLocalization using propagation timing Location tracked in real timeLocation tracked in real time Can be used to control servos for Can be used to control servos for

trackingtracking Spotlights, cameras, laser pointer, etcSpotlights, cameras, laser pointer, etc

FunctionFunction

1 mobile mote1 mobile mote 3 stationary motes3 stationary motes Mote communication established Mote communication established

through radio frequenciesthrough radio frequencies Localization calculated using Localization calculated using

propagation delay of ultrasound wavepropagation delay of ultrasound wave Servo motors follow the mobile mote Servo motors follow the mobile mote

in real timein real time

DesignDesign

Motes from CrossbowMotes from Crossbow

DesignDesign

Ultrasound TX/RX added to motesUltrasound TX/RX added to motes Mobile mote incorporates ultrasound Mobile mote incorporates ultrasound

TXTX Stationary mote incorporates Stationary mote incorporates

ultrasound RXultrasound RX TinyOS from Berkeley available TinyOS from Berkeley available

online to program motesonline to program motes

ImplementationImplementation

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

Mobile MoteStationary Mote

ImplementationImplementation

Stationary mote measures time Stationary mote measures time difference between radio and ultrasound difference between radio and ultrasound pulsepulse

Distance is calculatedDistance is calculated Position is found using multiple Position is found using multiple

stationary motesstationary motes Instructions given to servos for Instructions given to servos for

movement based on real time positionmovement based on real time position

ProblemsProblems

Integrating ultrasound devicesIntegrating ultrasound devices– We can build our own motes using We can build our own motes using

circuit diagrams from the MIT Cricket circuit diagrams from the MIT Cricket projectproject

– Just use radio strength data (less Just use radio strength data (less accurate)accurate)

Time delay in processing locationTime delay in processing location Might be easier to implement using Might be easier to implement using

UHF RFID RadarUHF RFID Radar

Mini-ProjectMini-Project

Implement the mote system using Implement the mote system using two motestwo motes

Ultrasound and radio communication Ultrasound and radio communication workingworking

Questions?Questions?