Smart Dust

1
Smart Dust

• Daniel Sturm

2
Outline

• Introduction
• Technology
• Devices
• Communication
• Challenges
• protocol
• Applications
• References

3
Introduction

• Smart Dust is a Wireless Sensor network.
• It consists of very small Devices.
• The motes are deployed randomly.

4
Introduction

• The Idea is a Brainchild of Kris Pister and
• Randy H. Katz at Berkeley University of California

Kris S.J. Pister
Randy H. Katz
Both are Professors of EE and CS at Berkeley.
5
Introduction

• But, it is still an idea...

6
Outline

• Introduction
• Technology
• Devices
• Communication
• Challenges
• protocol
• Applications
• References

7
Technology - Devices

• The Devices are called motes (?? - Stäubchen)
• They are planed to be 1-2 mm small.
• But the current development
• is at about 5-7 mm.

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Technology - Devices

• Each Smart Dust system also has
• a base-station transreceiver (BTS)
• It queries the information of the motes.

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Technology - Devices
Motes consists of

• Thick-film battery
• Solar cell
• Sensors
• Passive Transmitter with corner-cube
  retroreflector
• Active transmitter with laser diode and beam
  steer
• Receiver with photo detector

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Technology - Devices
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Technology - Devices

• In the Battery a total energy of about 1J is
  stored.
• It lasts for about one Day.
• Power consumption is roughly 10 µW.
• Solar cells can collect about 1J/day at sunlight
  and 1mJ/day at room light.

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Technology - Devices

• Battery power and energy saving technologies are
  the most important thing.

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Outline

• Introduction
• Technology
• Devices
• Communication
• Challenges
• protocol
• Applications
• References

14
Technology - Communication

• Communication is made optical.
• Because it has lower energy requirements,
• since it don't need modulation, active bandpass
  filters and demodulators.

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Technology - Communication

• The bandwidth is between 1bps and 1Mbps.
• And it has been successfully tested over 20 km.
• But more range effects less bandwidth.

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Technology - Communication

• There are two ways of Data transmission.
• Passive and Active.
• Passive is preferred due to less energy
  consumption.

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Technology - Communication

• Passive transmission happens with a corner-cube
  retroreflector
• It reflects a ray back to the source.
• Unless one mirror is misaligned.

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Technology - Communication

• The BTS sends a light ray to the motes.
• The light is reflected back or not,
• which means means 1 or 0.
• It is the usual way to communicate for the motes,
  only if there is no line of sight.

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Technology - Communication
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Technology - Communication

• The BTS communicate with multiple motes at the
  same time through space-division multiplexing.
• Each signal is sensed by a different part of the
  CCD.
• The motes must not be to close to each other.

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Technology - Communication
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Technology - Communication

• Active transmission happens when motes can not
  communicate passively.
• With a simple light transmitter and a
  photodetector.

23
Outline

• Introduction
• Technology
• Devices
• Communication
• Challenges
• protocol
• Applications
• References

24
Challenges - Protocol

• The Protocol is not yet developed.
• Speed is unimportant.
• Low energy costs are important

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Challenges - Protocol

• Limitations for development are
• Optical links requires uninterrupted line-of
  sight.
• The directional characteristic of the mote
  transmitter.
• Trade-offs between bit rate, energy per bit,
  distance and directionality.

26
Outline

• Introduction
• Technology
• Devices
• Communication
• Challenges
• protocol
• Applications
• References

27
Applications

• Smart Dust may be deployed over a region to
  record
• data for meteorological or geophysical research.
• Or it may be used in an environment that is
  unsuitable for wired sensors.

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Applications

• Smart Dust may be used to monitor the movement,
  habits, and environment of insects.
• Or used by the military to stealthy monitor
  hostile environment.

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Applications

• Smart Dust could be used to detect chemical or
  biological agents on the battlefield.
• Or it could even be used to observe YOU...

30
References

• 1 Joseph M. Kahn, Randy Howard Katz, and
  Kristofer S. J. Pister, Emerging Challenges
  Mobile Networking for Smart Dust, 2000 KICS
• 2 Brett Warneke, Matt Last, Brian Liebowitz,
  Kristofer S.J. Pister, Smart Dust Communicating
  with a Cubic-Millimeter Computer, 2001 IEEE
• 3 V.S. Hsu, J.M. Kahn, and K.S.J. Pister,
  Wireless Communications for Smart Dust, January
  30, 1998