New Computer Science Technology, very useful in future

1. Smart Dust
12BTCSE051
Anurag Srivastava

2. Introduction
 Smart Dust concept has been credited to researchers at the University of California,
Bekerley in 1997 by Prof. Kris Pister.
 Smart Dust is a self-contained network of tiny motes each having the capability of
sensing and monitoring the environment conditions.
 Often called micro electro-mechanical sensors (MEMS).
 They contain sensors which have the computational capability.
 They can communicate with a base station or with other motes depending on
the application.

3. Smart Dust Motes

4. Architecture
Small Smart Dust Has -
 A semiconductor laser diode and MEMS beam steering mirror for
active optical transmission.
 A MEMS Corner Cube Retro-reflector (CCR) for passive optical
transmission.
 An optical receiver.
 A signal processing and control circuitry.
 A power source based on thick-film batteries and solar cells.

5. SMART DUST COMPONENTS

6. MEMS
 Designers have used MEMS technology to build small sensors, optical
communication components and power supplies.
 MEMS consists of extremely tiny mechanical elements, often integrated
together with electronic circuitry.
 They are measured in micrometers that is millions of a meter. They are made in
a similar fashion as computer chips.

7. CCR
 CCR comprises three mutually perpendicular mirrors of gold-coated poly
silicon.
 The CCR has the property that any incident ray of light is reflected back to the
source.
 If one of the mirrors is misaligned, this retro-reflection property is spoiled.

8. CCR

9. Working
 Smart dust motes run by a microcontroller.
 Microcontrollers consist of tiny sensors for recording various
types of data.
 Sensors run by timers.
 Data is sent to the base controlling station
 Corner Cube Retro-Reflectors (CCR) built using MEMS
technique

10. Major Challenges
 It is difficult to fit all these devices in a small Smart Dust both size wise and
Energy wise.
 As the devices are so small, batteries present a massive addition of weight.
 High power consumption.
 Complicated design and mechanism.

11. Communication Technologies
 Radio Frequency Transmission
 Optical transmission technique :
a) Passive Laser based Communication
b) Active Laser based Communication
c) Fiber Optic Communication

12. Radio Frequency Transmission
 Based on the generation, propagation and detection of electromagnetic waves
with a frequency range from tens of kHz to hundreds of GHz.
 Multiplexing techniques: time, frequency.
 Their use leads to modulation, band pass filtering and additional circuitry, all
of which needs to be considered, based on power consumption.

13. Passive Laser based Communication
 Downlink communication - the base station points a modulated laser beam at a
node. Dust uses a simple optical receiver to decode the incoming message.
 Uplink communication - the base station points an un-modulated laser beam at
a node, which in turn modulates and reflects back the beam to the BST.

14. Active Laser based Communication
 Has a semiconductor laser, a collimating lens and a beam-steering micro-
mirror.
 Uses an active-steered laser-diode based transmitter to send a collimated laser
beam to a base station .
 Suitable for peer-to-peer communication, provided there exist a line of sight
path between the motes.

15. Fiber Optic Communication
 Employs semiconductor laser, fiber cable and diode receiver to generate,
transfer and detect the optical signal.
 Similar to passive optical communication .
 Relatively small size of the optical transceiver is employed with low-power
operation.
 CCR employed on each Dust mote to modulate uplink data to base station.

16. Application
 Security and Tracking
 Health and Wellness Monitoring (enter human bodies and check for
physiological problems).
 Factory and Process Automation.
 Seismic and Structural Monitoring.
 Monitor traffic and redirecting it.
 Exploring of planets.
 Detecting onset of diseases like cancer.

17. Advantage
 Small Size
 Better Connectivity
 Low Cost
 Useful in monitoring real world phenomenon without disturbing the original
process.

18. Disadvantages
 The main concern is privacy. Because it is so tiny, this device can be used to
spy on people without their approval.
 The air currents can also move them in the direction of flow.

19. Conclusion
 Smart dust is made up of thousands of sand-grain-sized sensors that can measure
ambient light and temperature. The sensors -- each one is called a "mote" -- have
wireless communications devices attached to them, and if you put a bunch of them near
each other, they'll network themselves automatically.
 Soon we will see Smart Dust being used in varied application from all spans of life.

20. References
 J. M. Kahn, R. H. Katz, K. S. J. Pister: Next Century Challenges: Mobile Networking
for “Smart Dust”
 An Introduction to Micro electro mechanical System Engineering: Nadim Maluf, Kirt
William
 B.A. Warneke, M.D. Scott, B.S. Leibowitz: Distributed Wireless Sensor Network
 http://www.coe.berkeley.edu/labnotes
 http://www.webopedia.com
 http://www.google.com