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Wireless Sensor Nets

Turning the Physical World into

Information

David CullerElectrical Engineering and Computer Sciences

University of California, Berkeley

http://www.cs.berkeley.edu/~culler

1/28/2004 Sensor Net Day 2

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Bell’s Law – new computer class per 10 years

year

log

(p

eo

ple

pe

r c

om

pu

ter)

streaming informationto/from physical world

Number CrunchingData Storage

productivityinteractive

• Enabled by technological opportunities

• Smaller, more numerous and more intimately connected

• Ushers in a new kind of application

• Ultimately used in many ways not previously imagined

1/28/2004 Sensor Net Day 3

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Technology Push

Itanium2 (241M )

nearly a thousand 8086’swould fit in a modern microprocessor

Processing & Storage

LNAmixerPLL basebandfilters

I Q

CommunicationSensingActuation

1/28/2004 Sensor Net Day 4

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Application Pull

• Env. Monitoring, Conservation biology, ...– Precision agriculture, land conservation, ...

– built environment comfort & efficiency ...

– alarms, security, surveillance, treaty verification ...

• Civil Engineering: structures response– condition-based maintenance

– disaster management

– urban terrain mapping & monitoring

• Interactive Environments– context aware computing, non-verbal

communication

– handicap assistance

» home/elder care

» asset tracking

• Integrated robotics

CENS.ucla.edu

1/28/2004 Sensor Net Day 5

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The Systems Challenge

applications

service

network

system

architecture

data mgmt

Monitoring & Managing Spaces and Things

technology

MEMSsensing Power

Comm. uRobotsactuate

Miniature, low-power connections to the physical world

Proc

Store

1/28/2004 Sensor Net Day 6

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Open Experimental Platform to Catalyze a Community

Small microcontroller

- 8 kb code,

- 512 B data

Simple, low-power radio

- 10 kb

EEPROM (32 KB)

Simple sensors

WeC 99“Smart Rock”

Mica 1/02

NEST open exp. platform

128 KB code, 4 KB data

50 KB radio

512 KB Flash

comm accelerators

- DARPA NEST

Dot 9/01

Demonstrate scale

- Intel

Rene 11/00

Designed for experimentation

-sensor boards

-power boards

DARPA SENSIT, Expeditions

TinyOS www.tinyos.net

Networking

Services

Crossbow

1/28/2004 Sensor Net Day 7

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NEST Pursuer/Evader Mid Term Demo

• Problem: detect vehicle entering sensitive area, track using magnetics, pursue and capture by UGV.

• Components– 10x10 array of robust wireless, self-localizing sensors over 400

m2 area– Low cost, robust ‘mote’ device: magnetometer, microcontroller,

radio network, ultrasonic transceiver– Evader: human controlled Rover– Pursuer: autonomous rover with mote, embedded PC, GPS

• Operation– Nodes inter-range (Ultrasonic) and self localize from few

anchors, correct for earth mag, go into low-power ‘sentry’ state– Detect entry and track evader

» Local mag signal processing determines event and announces to neighbors

» Neighborhood aggregates and estimates position» Network routes estimate from leader to tracker (multihop)

– Pursuer enters and navigates to intercede» Motes detect and estimate multiple events» Route to mobile Pursuer node» Disambiguates events to form map» Closed inner-loop navigation control» Closed information-driven pursuit control» Capture when within one meterdot

mag ultrasound

acousticultrasound

mainmag sense

power

battery

reflector

pursuer

evader

1/28/2004 Sensor Net Day 8

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Making it happen

Tackle the new computer systems challenges due resource constraints, scale, & embedment

Fundamentally simpler, more robust software structures

Demonstrate applications that show how it can change the way we do science and what we can shoot for.

Ecophysiology, conservation biology

Demonstrate applications that show how it can change the way we do engineering

Structural response, condition based maintanance

Deep collaboration between academia, industry, and government from the beginning