Smart Dust

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Smart Dust Its Applications

• By
• PANKAJ SHARMA

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OUTLINE

1. INTRODUCTION
2. ARCHITECTURE
3. MANUFACTURING
4. COMM. INTERFACE
5. SENSOR NETWORKS
6. APPLICATIONS
7. THE DARK SIDE
8. RESEARCH AREAS
9. CONCLUSION

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INTRODUCTION

• Technology developed at UCLA Berkeley college
  of Engg.
• Small wireless devices designed to monitor all
  types of
• physical quantities such as
• Temperature
• Humidity
• Motion
• Light Levels
• Pollution etc.
• Commercial name coined for dust size smart
  sensors.

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INTRODUCTION
POWER SUPPLY
PROCESSOR
RECEIVER
TRANSMITTER

• Level of Integration Integrates
• Transducers
• Processors
• Memories
• Solar powered Batteries
• Communication Interfaces on a single micro
  miniscule
• silicon chip.
• Uses MEMS technology for its fabrication

SENSORS
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INTRODUCTION Questions

• What Are Sensors?
• A device that responds to a physical stimulus
  for eg. Heat Light, sound, pressure, motion, flow
  etc and produces a measurable Corresponding
  electrical signal is called a sensor.
• What Are Smart Sensors?
• Sensors which not only have the capability to
  respond to a physical stimulus but also the
  ability to decide whether the data is useful or
  not.

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INTRODUCTION Questions
Why Smart Sensors?

• Smart Sensors
• Programmable
• Decision Making Capability
• Self Calibrating
• Plug-n-Play Operation
• Sophisticated Complex
• sensor systems are easy to design

• Traditional Sensors
• Not Programmable
• No processing power
• Custom Calibration
• Custom design
• Very difficult with
• traditional methods

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INTRODUCTION Questions
Why Smart Sensors?

• Smart Sensors
• Distributed Measurements
• Possible
• Low Cost Wide Availability
• Less Maintenance Cost

• Traditional Sensors
• Only Lumped measurements
• possible
• Relatively High Cost
• Requires skilled Professionals
• for repair job

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ARCHITECTURE
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Thin Film Battery

• Size 1x1x1mm3
• Storage 1 Joule
• Material Lithium ion
• Low o/p resistance for sub milli-amp current

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Power Capacitor

• Size 0.25x0.25x0.25mm3
• Capacity 1 micro joule
• Material Ceramic
• Used to provide high current when needed
• for eg. For laser pulses

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Solar Cell

• Size 1x1x0.1mm3
• Generation Cap. 1 joule/day/mm
• Material Photosensitive compounds
• Used to power the smart dust unit

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Controller

• Size 1x1x0.1mm3
• Uses CMOS technology
• Analog cum digital controller
• Gives the dust mote the decision making
  capability

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Sensors

• Size 0.5x0.5x0.1mm3
• Incorporates many sensors on one interface
• Micromachining techniques used for fabrication

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Passive Transmitter
Interrogating Laser Beam

• Called Corner Cube Retro-reflector (CCR)
• Size 0.5x0.5x0.1mm3
• Range 1Km
• Speed 100kbps
• Modulates interrogating laser beam with the help
  of movable mirrors transmits it

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Active Transmitter

• Size 1x0.5x0.1mm3
• Range 10Km
• Speed 10Mbps
• Uses laser diode to produce carrier beam.

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Receiver

• Size 1x0.5x0.1mm3
• Consists of photodetector and receiver circuitry
• Demodulates the incoming signal and separates the
  useful information from carrier noise

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MANUFACTURING Introduction to MEMS

• These dust size particles are fabricated using
  MEMS technology.
• MEMS devices dates way back to 1958
• 1st application was a Strain Gauge
• Uses silicon as base material and etching
  techniques to generate pattern therein

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MANUFACTURING Introduction to MEMS

• Combines two Technologies
• IC fabrication Technology
• Micromachining Technology
• IC Fabrication - used to etch electronic
  circuits on the silicon substrate
• Micromachining -used to etch mechanical patterns
  on the silicon substrate

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MANUFACTURING Fabrication Process

• MEMS Generic Process

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MANUFACTURING

• Includes Two Types of Micromachining Processes
• BULK MICROMACHINING
• SURFACE MICROMACHINING

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MANUFACTURING

• Bulk Micromachining
• Wet chemicals are used to etch the pattern on
  silicon substrate.
• Etchants used-
• Non Acidic-
• Potassium hydroxide (KOH)
• Tetra methyl ammonium hydroxide (TMAH)
• Ethylene Diamene Pyrocatechol (EDP)
• Acidic-
• Hydroflouric Acidic
• Nitric Acid

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MANUFACTURING

• Bulk Micromachining
• Process involves-
• Depositing masking Layers of-
• Silicon nitride or
• Silicon dioxide or any
• Metal like Au, Ti, etc.
• Patterning these using Lithography

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MANUFACTURING

• Bulk Micromachining
• Pressure sensors Accelerometers are fabricated
  using these technologies.
• These devices include fabrication of
  peizo-resistors on one side of wafer and
  machining on the other side to form diaphragm or
  suspended mass in the case of pressure sensor or
  accelerometers respectively.

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MANUFACTURING
Peizo-electric material

• Bulk Micromachining
• Pressure Sensor
• Accelerometer

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MANUFACTURING

• 2. Surface Micromachining
• More advanced technique to make Novel structures
  on surface of silicon wafer
• Involves deposition of certain layers and
  patterning these using Lithographic And etching
  techniques.

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MANUFACTURING

• 2. Surface Micromachining
• Mainly Three layers are employed
• Electrical layer Conducts electrical signals to
  and from MEMS structure.
• Structural layer Forms The mechanical Body of
  MEMS.
• Sacrificial layer Serve the purpose of releasing
  the structural layers.

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COMMUNICATION INTERFACE

• System Design Options
• Must support half- or full-duplex, bi-directional
  communication between a central transceiver and
  up to 1000 dust motes.
• The downlink (central transceiver to dust motes)
  must broadcast to all of the dust motes at a bit
  rate of several kbps.
• The uplink (dust motes to central transceiver)
  must permit each of 1000 dust motes to convey
  about 1 kb of data within 1 s, an aggregate
  throughput of 1 Mbps.

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COMMUNICATION INTERFACE

• System Design Options
• Options for uplink multiplexing include time-,
  frequency-, code- and space-division
  multiplexing.
• The central transceiver must be able to resolve
  the position of each dust mote with an angular
  resolution of the order of 1/100 of the field of
  view.
• The link should operate over a range of at least
  several hundred meters.

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COMMUNICATION INTERFACE

• System Design Options
• The dust mote transceiver must occupy a volume of
  the order of 1 mm3, and consume an average power
  not exceeding 1 mW.
• If possible, the uplink and downlink should
  afford a low probability of interception

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COMMUNICATION INTERFACETypes

• Radio Frequency Transmission (RFT)
• Time Division MUX (TDMA)
• Frequency Division MUX (FDMA)
• Code Division MUX (CDMA)
• Space Division MUX (SDMA)
• Free Space Optical Transmission (FSOT)
• Passive Transmission
• Active Transmission

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COMMUNICATION INTERFACE
Why FSOT is preferred?

• Pitfalls of RFT
• Problems with TDMA
• Requires each dust mote to coordinate its
  transmission with all the other dust motes.
• Problems with FDMA
• requires accurate control of the dust-mote
  oscillator frequency

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COMMUNICATION INTERFACE
Why FSOT is preferred?

• Pitfalls of RFT
• Problems with CDMA
• Requires high-speed digital circuitry to operate
  for a relatively extended time interval,
  potentially consuming excessive power.
• In order to avoid coordination between dust
  motes, both FDMA and CDMA require individual dust
  motes to be preprogrammed with unique frequencies
  or codes

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COMMUNICATION INTERFACE
Why FSOT is preferred?

• Pitfalls of RFT
• Problems with SDMA
• In SDMA, the central transceiver employs an
  antenna array to separate transmissions from
  different dust motes. Given the limited size of
  the central transceiver it would be difficult for
  SDMA to achieve the required spatial resolution.

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COMMUNICATION INTERFACE
Why FSOT is preferred?

• Advantages of FSOT
• Free-space optical transmission at visible or
  near-infrared wavelengths (400-1600 nm)
  represents an attractive alternative for the
  downlink and uplink.
• In downlinking-
• A single laser transmitter can broadcast an on
  off-keyed signal to the collection of dust motes.
  
• Each dust mote would be equipped with a very
  simple receiver consisting of a band pass optical
  filter, a photodiode, a preamplifier and a
  slicer.
• This receiver would involve only low-speed
  base-band electronics, making it far simpler than
  its RF counterpart.

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COMMUNICATION INTERFACE
Why FSOT is preferred?

• Advantages of FSOT
• In uplinking-
• optics offers two alternatives for transmission.
• Active laser-diode-based transmitter
• Involves modulation of internally generated laser
  beam
• Optically passive transmitter consisting of a
  corner-cube retro-reflector (CCR).
• Involves modulation of external interrogating
  beam.

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COMMUNICATION INTERFACE
Lens
Which One To Prefer?
Adjustable Mirror
Laser Diode

• Active Transmitter
• Consumes a lot of power to generate the laser
  beam
• Passive Transmitter
• Involves a corner cube retroreflector to modulate
  the interrogating beam from the central receiver.
• Requires a lot less power than its active
  counterpart.

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COMMUNICATION INTERFACE
System Realization
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DISTRIBUTED SENSOR NETWORKS

• Consists of a Network backbone on which many
  nodes reside.
• Nodes are classified as
• Sensor nodes- tend to send data to the network
• Controller nodes- tend to gather data from the
  network
• There can be more than one controller node.
• Virtual network via internet can also be setup

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DISTRIBUTED SENSOR NETWORKS
Networked Smart Dust Sensors
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DISTRIBUTED SENSOR NETWORKS

• Controller Nodes
• Consists of
• Processor
• Memory
• Network Interface
• I/O devices to communicate with the users
• Used to
• Collect information from sensor nodes
• Program the sensor nodes
• Provide feedback to the user

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DISTRIBUTED SENSOR NETWORKS

• Advantages of Sensor Networks
• Plug-n-Play operation possible
• No new wires to be routed to accommodate new
  nodes
• Traditional sensors have varying gains, offsets,
  hysteresis, etc. which must be compensated for
  elsewhere in the system. A smart sensor node
  would store the physical attributes of the
  transducer and would compensate for non
  idealities locally in the processor.

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DISTRIBUTED SENSOR NETWORKS
THE IEEE 1451 PROTOCOL

• It is an open standard that gives sensors makers
  a way to interface to different types of field
  buses
• A standard transducer interface module (STIM)
  described by the standard includes
• sensor interface
• signal conditioning and conversion
• calibration
• linearization and
• basic communication rules

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DISTRIBUTED SENSOR NETWORKS
TEDS the Heart of IEEE 1451 Protocol

• TEDS stands for Transducer Electronic Data Sheet.
• Contains Technical information that
• identifies the sensor
• specifies the sensors analog interface and
• describes the sensors use
• TEDS resides in the sensor in an inexpensive
  memory component, typically an EEPROM,

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DISTRIBUTED SENSOR NETWORKS
TEDS

• Consists of four fields
• Basic TEDS
• Standard TEDS
• Calibration TEDS
• User area
• Contents vary according to the type of sensor

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DISTRIBUTED SENSOR NETWORKS

• Advantages of IEEE 1451
• Maximum Compatibility
• Simple Adoption
• Quicker, more automated system setup
• Improved diagnostics and troubleshooting
• Reduced downtime for sensor repair and
  replacement
• Improved sensor data management, bookkeeping, and
  inventory management
• Automated use of calibration data

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APPLICATIONS

• Military Applications
• Battlefield surveillance
• Detection
• Classification
• Tracking of enemy vehicles.
• Eg. DARPA SensIT Project

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APPLICATIONS

• Dust Particles can be spread by Unmanned Air
  Vehicles (UAVs)
• Data can be collected by sending the same
  aircraft over that area

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APPLICATIONS

• VIRTUAL KEYBOARD
• Glue some dust motes to your fingertips
• Accelerometers will sense the orientation and
  motion of each of your fingertips, and talk to
  the computer in your watch
• Then
• Sculpt 3D shapes in virtual clay
• Play  the piano
• Gesture in sign language and have the computer to
  translate
• Combined with a MEMS augmented-reality heads-up
  display, your entire computer I/O would be
  invisible to the people around you.
• Couple that with wireless access and you need
  never be bored in a meeting again!  Surf the web
  while the boss rambles on and on.

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APPLICATIONS

• INVENTORY CONTROL
• The carton talks to the box
• The box talks to the palette
• The palette talks to the truck
• The truck talks to the warehouse
• and the truck and the warehouse talk to the
  internet.
• Know where your products are and what shape
  they're in any time, anywhere.

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APPLICATIONS

• ENVIRONMENTAL APPLICATIONS
• Habitat Monitoring
• Eg ZebraNet(Princeton)
• Weather sensing
• Estuarine environmental and observation
  forecasting system (EEOFS)

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APPLICATIONS

• ROAD WEATHER OBSERVATION

The Overlapping Environmental Observation
Transportation Surveillance system
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APPLICATIONS

• HEALTH APPLICATIONS
• Tele-monitoring human Psychological Data
• Tracking and monitoring of doctors and patients
  inside the hospitals.
• Personal health monitor application running on a
  PDA receives and analyzes data from a number of
  sensors (e.g., ECG, EMG, blood pressure, pulse
  oxymeter)
• Glucose level Monitors.
• Cancer detectors and general health monitors.

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APPLICATIONS

• BIOMEDICAL SENSORS

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APPLICATIONS

• INTERFACES FOR QUADRIPLEGICS
• Put motes "on a quadriplegic's face, to monitor
  blinking facial twitches-and send them as
  commands to a wheelchair/computer/other device
• AUTOMOBILES
• Accelerometers find the biggest use in
  automobiles, mainly in airbag safety systems to
  detect the collision impact and inflate the
  airbags to protect the passengers.
• Measurement of Tyre pressure and its treading
  even during motion.

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THE DARK SIDE

• PRIVACY GOING PUBLIC
• As the technology is becoming smaller smaller
  personal information has been under a lot of
  threat
• So some privacy laws should be implemented before
  implementing this technology commercially.
• ENVIRONMENTAL IMPACT
• A lot of you might be worried about inhaling a
  dust mote
• Dont worry, even if intel stopped producing
  Pentium products and produced only dust motes, we
  won,t produce too many to bother anyone.

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RESEARCH AREAS

• Efficient data conversion within the smart sensor
  node is a fundamental key to its success.
• One may attempt to devise a small, efficient
  instruction set with which to program nodes for a
  wide variety of functions.
• Plug and play functionality requires a standard
  interface that communicates a node's identity and
  capabilities. The upcoming IEEE 1451 standard
  provides a basic communications link for sensor
  nodes, but provides no methods specific to
  programming a node's data processing resources
• One may design a standard interface that
  standardizes the dynamic programming of sensor
  nodes.

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RESEARCH AREAS

• Other areas of research
• Designing Tiny Operating systems
• Designing CAD tools for developing such
  applications
• Design tools to monitor sensor networks
• And many areas which are creeping in your mind

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CONCLUSION

• With the base technology of manufacturing ICs
  already available in our country and just by
  employing a little extra on micro-fabrication
  technology the Indian firms like BEL, SCL and
  other semiconductors giants can take the
  initiative to conquer the world markets in this
  sector and take India into a dominating position
  as in the IT sector. The employment of smart dust
  would mean better measurement data, therefore a
  better control of various industrial and non
  industrial parameters, and thereby enhancing the
  standard of life in general.

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THANK YOU
SMART DUST A CHALLENGE TO OUR GENERATION

• PANKAJ SHARMA

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• QUERIES