SMART DUST

SMART DUSTK. Pister, J. Kahn, B. Boser

(UCB)S. Morris

(MLB)

MEMSMTO

DARPADARPA

SMART DUST

Goals

• Autonomous sensor node (mote) in 1 mm3

• MAV delivery

• Thousands of motes

• Many interrogators

• Demonstrate useful/complex integration in 1 mm3

SMART DUST

COTS Dust

GOALS:

• Create a network of sensors

• Explore system design issues

• Provide a platform to test Dust components

• Use off the shelf components

SMART DUST

COTS Dust - RF Motes

• Atmel Microprocessor• RF Monolithics transceiver

• 916MHz, ~20m range, 4800 bps• 1 week fully active, 2 yr @1%

N

S

EW 2 Axis Magnetic Sensor

2 Axis Accelerometer

Light Intensity Sensor

Humidity Sensor

Pressure Sensor

Temperature Sensor

SMART DUST

COTS Dust - Network Simulation

Cheap platforms --> Lots of nodes -->Network challenges!

SMART DUST

Message Diffusion (McLurkin)

• Each mote checks all it’s received transmissions for the one with the maximum value

• The mote then rebroadcasts it with a lower value

• The result is a gradient pointing towards the signal source.

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-0.5

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Number Of Motes=200Communications Range=.5

SMART DUST

Edge Detection using Min/Max• 1. Ask each or your

neighbors how many motes they can see.

• 2. Find the minimum and maximum of these numbers

• 3. Share these minimum and maximum numbers with all your neighbors.

• 4. When all your neighbors have the same min.max info as you, compare your local neighbor count to this info.

• 5. Turn red if you are lonely0 0.5 1 1.5 2 2.5 3 3.5 4

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Number Of Motes=500Communications Range=.5

SMART DUST

0 1 2 3 4 5-1

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Gradient Directed Communication

• These gradients can be used to direct• transmissions towards a single source

• Messenger Agents (the light blue dots) transmit themselves to motes with higher message levels

• This provides the minimum number of hops to get to a central destination

Number Of Motes=150Communications Range=1

SMART DUST

-0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5-1

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Centroid Location• Find edges

• Diffuse pheromone from the edges inward

• Find the lowest concentration using Min/Max sharing

• If you have the lowest concentration, turn yellow

Number Of Motes=500Communications Range=.8

SMART DUST

Mote Position Estimation

• Give GPS receivers to some motes and callthem “BasisMotes”. Ask them to turn gray.

• Each BasisMote diffuses it’s own pheromone throughout the group

• The position of any other mote can be estimated from the levels of basis pheromones present.

SMART DUST

Network Growing

• Since diffusion directed communication already minimizes number of hops, whatever are we going to optimize?

• We can use division of labor to optimize power (time)

• Certain motes are responsible for communications to the hub and others are responsible for sensing

Number Of Motes=128Communications Range=1

SMART DUST

COTS Dust - Optical Motes

Laser mote

• 650nm laser pointer

• 2 day life full duty

CCR mote

• 4 corner cubes

• 40% hemisphere

SMART DUST

CCR Interogator

Top View of the Interrogator

CCD Camera Lens

Frequency-Doubled Beam45o mirror

Polarizing Beamsplitter

Quarter-wavePlateFilter

0.25% reflectance on each surface

YAG Green Laser Expander

SMART DUST

Video Semaphore Decoding

Diverged beam @ 300m

Shadow or full sunlight

Diverged beam @ 5.2 km

In shadow in evening sun

SMART DUST

Video Semaphore Decoding

Diverged beam @ 300m

Shadow or full sunlight

Diverged beam @ 5.2 km

In shadow in evening sun

SMART DUST

1 Mbps CMOS imaging receiver

1 0 cm

20 0 m

F ield of Viewof S ingle P ixel

5 m m

2 k m

CollectionLens

OpticalF ilter

64x64CMOSImager

10W, 1mrad

Photosensor

Signal ProcessingA/D Conversion

SIPO ShiftRegister

CRC CheckLocal Bus Driver

Off ChipBus Driver

Pixel Array

SMART DUST

Optical Communication (vs. RF)

• Pro:• low power• small aperture• spatial division multiplexing• high data rates• LPI/LPD• baseband coding

• Con:• line of sight• atmospheric turbulence

SMART DUST

Turbulent Channel

La ser

R ece ive r

v

C omm un ica tion throug h Tu rbu le nt A tmos phe re

To S ig na l

Edd ies

De te ction

M ax im um-L ik elihood

0 11 1 0 1

2

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13

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21 3

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1 3

1234

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311

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Se que nc e De tec tion Algorithm

Phy sica l Origin of B ea m Scintillation

Ed d ie s

SMART DUST

Micro Mote - First Attempt

SMART DUST

2D beam scanning

laser

lens

CMOS ASIC

Steering Mirror

AR coated dome

SMART DUST

6-bit DAC Driving Scanning Mirror

10 20 30 400

0.2

0.4

0.6

0.8

Time (seconds)

Nor

mal

ized

bea

m p

ositi

on

• Open loop control

• Insensitive to disturbance

• Potentially low power

SMART DUST

Power and Energy

• Sources• Solar cells• Thermopiles

• Storage• Batteries ~1 J/mm3

• Capacitors ~1 J/mm3

• Usage• Digital control: nW• Analog circuitry: nJ/sample• Communication: nJ/bit

SMART DUST

’01 Goal

SMART DUST

MAV Delivery

• 60 mph

• 18 min

• 1 mi comm

Built by MLB Co.

SMART DUST

Dust Delivery

• Floaters

• Autorotators• solar cells

• Rockets• thermopiles

• MAVs

LO

AD

MO

TE

SMART DUST

Micro Flying Insect

• ONR MURI/ DARPA funded

• year 1 of 5 year project

• Dickinson, Fearing (PI), Liepmann, Majumdar, Pister, Sands, Sastry

• Heavily leveraged on Smart Dust

SMART DUST

Applications

• DoD• Battlefield sensor networks• Sensor mine-fields, burrs and fleas• Traffic mapping• Captured terrain surveillance• Bunker mapping• ...

• Civilian• High speed/low power IRDA• Interactive virtual ballet• ...

SMART DUST

The (somewhat) Virtual Keyboard

SMART DUST

Data from ACC-glove

SMART DUST

Conclusion

• Cubic inch motes off-the-shelf, ~$100• Dec ’99: 100 node network in Soda/Cory• Desperately need intelligent software

• Millimeter-scale motes• Dec ’00: first working prototypes• Don’t have a clue what we need in software