SMART DUST K. Pister, J. Kahn, B. Boser (UCB) S. Morris (MLB) MEMSMTO DARPA.

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

0

0.5

1

1.5

2

2.5

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3.5

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

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Number Of Motes=500Communications Range=.5

SMART DUST

0 1 2 3 4 5-1

0

1

2

3

4

5

6

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

0

1

2

3

4

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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

2

1

4

13

2

2

1

13

2

2

1

13

2

2

1

13

3

2

21 3

3

1 3

1234

13

13

311

3

23

23

2

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