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Active Bat: A 3D Location Device

http://www.uk.research.att.com/bat/

-- presented by Yu-Chee Tseng --

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Goal

Low-power wireless inexpensive fine-grain 3D positioning sensor

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Theory

medium: ultrasonic

method: triangulation an emitter is attached to an

object receivers are mounted on the

wall we measure the times-of-flight

of the pulse to the receivers the speed of sound is known

given 3 or more distances, we can determine the 3D location of the object

by keeping track of the 3D locations, we can determine the orientation and speed of the object

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Hardware

prototype of ultrasonic transmitter:5.5cm x 3cm x 2.4cm30 g3-month life timea unique 16-bit address

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Receivers

mounted on the walleach 1.2 m apartnetworked to a PC

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Results

accuracy = 10 cm (in each of the 3 dimensions) can find 25 objects per second

Watch demo “active-bat.mpg” (from ORL).

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Applications

Sentient computing systemAT&T Lab, Cambridge.Personnel carry wireless devices – Bats.Sensors locates on the ceiling.Functions

Spatial monitor (for browsing on the Web)Follow-me systemsData creation, storage, and retrieval

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Applications

1. trigger2. emit signals3. positioning by TOA

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Applications