SYBIL C ANIYANROLL NO:56

MCA B5

Overview

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What is Smart Dust?HistorySmart Dust ComponentsSmart Dust NetworkingApplicationsAttributesLimitationsDelivery and InterrogationConclusion

What is Smart Dust? “SMART DUST” is an autonomous sensing, computing,

communication and power source in a cubic millimeter Small devices that can collect information from on-board

sensors and transmit it over a wireless network that automatically sets itself up

Also called “Motes” Possible sensors include temperature, relative humidity,

illumination, acceleration, magnetic field, pressure, chemical vapors, camera, microphone, …

These “motes” have memories, microprocessor,

radio receiver and transmitter3

History

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Conceived by Dr. Kris Pister of UC Berkeley

Funded by DARPA (Dept. of Defense) Kris Pister

Clever Dust

Golem Dust with Deputy Dust

Golem Dust

Daft Dust

Flashy Dust

The Generations of Smart Dust Motes

Smart Dust Components

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Contd…

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Thick film battery: 1mm^3, 1 J storagePower capacitor: 0.25mm^3, 1uJ storageSolar cell: 1x1x0.1mm^3, 0.1mW generationCMOS controller: 1x1x0.1mm^3Sensor: 0.5x0.5x0.1mm^3Passive CCR comm: 0.5x0.5x0.1mm^3, 10kbps, 1uW, 1kmActive laser comm: 1x0.5x0.1mm^3, 1Mbps, 10mW, 10kmTotal volume: < 1.5 mm^3Total mass: < 5 mgm

Smart Dust Networking

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A collection of motes is dispersed in an environment

Motes use wireless communications to relay information to a base station (gateway) over distances of 15-50 m.

How the communication occurs?

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The smart dust mote is run by a microcontroller that not only determines the task performed by the mote, but consists of the power to the various components of the system to conserve energy. Periodically the micro controller gets a reading from one of the sensors, which measure one of a number of physical or chemical stimuli and store it in memory. It also turns on optical receiver to see if anyone is trying to communicate with it. This communication may include new programs or messages from other motes. In response to a message or upon its own initiative, the microcontroller will use the corner cube retro reflector(CCR) or laser to transmit sensor data or a message to a base station or another mote.

Contd…

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The primary constraint in the design of the Smart Dust motes is volume, which in turn puts a severe constraint on energy since we do not have much room for batteries or large solar cells. Thus, the motes must operate efficiently and conserve energy whenever possible. Most of the time, the majority of the mote is powered off with only a clock and a few timers running. When a timer expires, it powers up a part of the mote to carry out a job, then powers off. A few of the timers control the sensors that measure one of a number of physical or chemical stimuli such as temperature, ambient light, vibration, acceleration, or air pressure.

Contd…

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When one of these timers expires, it powers up the corresponding sensor, takes a sample, and converts it to a digital word. If the data is interesting, it may either be stored directly in the SRAM or the microcontroller is powered up to perform more complex operations with it. When this task is complete, everything is again powered down and the timer begins counting again.

 

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It can be in 3 ways

Radio-Frequency Communications

Optical Communication: passive dust mode transmitters

Optical Communication: active dust mode transmitters

Radio-Frequency Communications

Radio frequency communication is one of the well-developed communication systems.

It is based on the generation, propagation and detection of electromagnetic waves with a frequency range from tens of kHz to hundreds of GHz.

It could be used to function as both the uplink and the downlink.

Radio-Frequency Communications Pros

Long rangeLine-of-sight path not requiredNot severely affected by rain, fog or atmospheric

turbulence Cons

Antenna may be too large for dust motesRequires modulator, demodulator, filtering (power

consumption)Requires complex multiplexing scheme (TDMA,

FDMA, CDMA)

Optical Communication (Passive Dust Mote Transmitters)

DownlinkLaser

U plink

CCD Corner-Cube

Upl ink

Data In

Data

Im ageSensor

Retroreflector

D ata In

Photo-

DownlinkData Out

detector

B ase-S tation Transceiver

Dust M ote

S ignal Selectionand P rocessing

UplinkData . . .

OutNOut1

Array

Unm odulated Interrogation

M odulated Reflected

Lens

Lens

M odulated Downlink Data or

B eam for Uplink

B eam for Uplink

Attractive communication option for uplink and downlink

Corner Cube Reflector (CCR)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

Contd...

Requires each dust mote to have a line-of-sight path to the base station.

Uplink transmissions are multiplexed using space-division multiplexing.

Transmitter Radiant Intensity

Receiver Light Collection Area

Base

TransceiverStation

DustMote

DustMote

Contd… Pros

Dust motes need not radiate power, nor steer beamExploits asymmetry: powerful base station, low-power dust

motesUtilizes space-division multiplexingOnly baseband electronics are required

ConsRequires line-of-sight path to base stationShort range (up to about 1 km)Bit rate limited to about 10 kbpsAffected by rain, fog, atmospheric turbulence

(Active Dust Mote Transmitter)

LaserCollimating

Beam

Mirror(s)

Lens

Steering

Diode

Two-axis beam steering assembly

Active dust mote transmitter

It uses an active steered onboard laser diode based transmitter to send a collimated laser beam to a station

Contd…

It consist of a laser diode, collimating mirror and beam steering mirrors for the communication.

It is suitable for peer to peer communication.

Transmitter Radiant IntensityReceiver Light Collection Area

Base

TransceiverStation

DustMote

DustMote

DustMote

Contd… Pros

Longer range than passive links (up to about 10 km)Higher bit rates than passive links (up to about 1 Mbps)With multi-hop, avoids need for every dust mote to have

line-of-sight path to base stationUtilizes space-division multiplexingOnly baseband electronics are required

ConsRequires protocol to steer directional transmittersRequires higher power than passive transmitterAffected by rain, fog, atmospheric turbulence

Applications

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Out of range vibrations in industrial equipment to catch manufacturing defects

Hospital monitoring of patient movements / monitoring the elderly while allowing freedom of movement

Environmental monitoring

Traffic sensors in urban areas

Monitor power consumption of household appliances

Cosmetics company monitoring warehouse humidity

Measuring structural integrity of a building

Some field Applications

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Micro-radio 50 times smaller than a cell phone 1,000 times less power consumption same frequency in conventional radios, transmitting half a watt can

consume three watts goal: transmit a few hundred microwatts with just a

milliwatt

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Monitoring Onboard Machinery

Purpose:• Predict machinery failure

Implementation:• 160 motes near ship’s

pumps, compressors, and engines

• Motes look for unusual vibration or motion

Challenge:• Harsh marine environment

Image Sources: www.aurora-environmental.com, www.bp.com

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Grocery Store – Energy Mgmt.

Dan Bertocchini - Energy Manager

Image Sources: www.gettyimages.com, www.supervalu.com

• Determine energy use of equipment

• Pinpoint machines which need repair

• Saves $ - Firm moves one set of smart dust between many stores

Some future applications

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Forest Fire Detection

Implementation• Drop smart dust from an

airplane• Motes self-organize into a

networkUsage• A mote that detects a fire

notifies central monitoring station

• The mote’s location is the approximate location of the fire.

Image Sources: http://science.nasa.gov,USDA Forest Service - www.fs.fed.us

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Spotting Pipe Corrosion

Benefits

• Inspect pipes without crawling in tight spaces

• No need to remove insulation to inspect pipe

• Up to date status

Image Source: gettyimages.com

Attributes

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Physical attributes

o Small and lightweight

o Low power consumption

Ad-hoc networking capabilities

o Networking functions are seamless and automatic

o Multiple networks can be in use simultaneously

Cont………

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Data transmission capabilities

o On-board data acquisition supports many missions

o Software support for many sensor configurations

o Data can be carried through network to command centres

Ubiquity and redundancy in use

o Multiple motes can be available on every device/person

o Motes can be strewn in large numbers

Limitations

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Line of sightoDirect optical communication to BTS idealoMultihop possible, but limitedoIncreases bandwidth densities, but decreases connectivity

Link DirectionalityoCan focus interrogation subset of “viewable” sensorsoLimits mote visibility and connectivity to a hemisphereoInteresting connectivity, routing, and interlaced network challenges

Contd…

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Low Throughput ( < 10 Kbps )

o Suited for data monitoring, not real-time audio

Power Source

o RF communications circuits drain a lot of power

o Need advancement in battery technology

Size

o Many RF communications components -> difficult to reduce size

Contd…

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Cost

o Current motes cost between $50 - $100 each

Intrusive probes

o A number of political, environmental, health and privacy related questions

Delivery and Interrogation

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Delivery SystemsoManualoMicro air vehicleoProjectileoWind-borne (“maple seeds”)

InterrogationoHand-held “binoculars”oMicro air vehicle

Manual

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Micro Air Vehicle

Air delivery

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Battle Field

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Smart Dust Today

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$40 to $150 each (depends on purchase volume)

CPU: Atmel :4 kb SRAMRadio: ChipconExternal Flash: 512kbPowered by 2AA batteries

MICA2

Smart Dust Today

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$40 to $150 each (depends on purchase volume)

CPU: Atmel :4 kb SRAMRadio: ChipconExternal Flash: 512kbPowered by 3V lithium coin cell

MICA2DOT

Smart Dust Tomorrow

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Motes will betinyInexpensivelong lasting

CONCLUSION

Smart dust motes incorporate sensing, computation, communications and power in a mm3 volume.

Free-space optical communication offers advantages in terms of size, power and network throughput.

On the technology

• Software and hardware are open-source

• Many potential civilian and military applications

• Promising technology if cost goes down

On regulatory aspects

• Investigate their impact on existing services

• Low power device