1. ActiveBat:1 WirelessNet Tseng Active Bat: A 3D Location Device http://www.uk.research.att.com/bat/ -- presented by Yu-Chee Tseng --

2. ActiveBat:2 WirelessNet Tseng Goal  Low-power  wireless  inexpensive  fine-grain 3D positioning sensor

3. ActiveBat:3 WirelessNet Tseng 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

4. ActiveBat:4 WirelessNet Tseng Hardware  prototype of ultrasonic transmitter: 5.5cm x 3cm x 2.4cm 30 g 3-month life time a unique 16-bit address

5. ActiveBat:5 WirelessNet Tseng Receivers  mounted on the wall each 1.2 m apart networked to a PC

6. ActiveBat:6 WirelessNet Tseng Results  accuracy = 10 cm (in each of the 3 dimensions)  can find 25 objects per second  Watch demo “active-bat.mpg” (from ORL).

7. ActiveBat:7 WirelessNet Tseng Applications  Sentient computing system AT&T Lab, Cambridge. Personnel carry wireless devices – Bats. Sensors locates on the ceiling. Functions  Spatial monitor (for browsing on the Web)  Follow-me systems  Data creation, storage, and retrieval

8. ActiveBat:8 WirelessNet Tseng Applications 1. trigger 2. emit signals 3. positioning by TOA

9. ActiveBat:9 WirelessNet Tseng Applications