25-07-2012, 11:42 AM
SMART DUST TECHNOLOGY
FINAL SMART DUST PPT.pptx (Size: 1.64 MB / Downloads: 44)
SMART DUST-ORIGIN
1990s Kris Pester.
Dreamt of a future in which people will sprinkle the surface of the earth with countless tiny sensors.
Idea was to monitor the earth’s climate on a real time basis.
What is Smart Dust?
A tiny dust size device with extra-ordinary capabilities.
Often called micro electro-mechanical sensors
Combines sensing, computing, wireless communication capabilities
autonomous power supply within volume of only few millimeters.
Cont…
So small and light in weight that they can remain suspended in the environment like an ordinary dust particle.
The air currents can also move them in the direction of flow.
It is very hard to detect the presence of the Smart Dust and it is even harder to get rid of them once deployed.
SPECIFICATIONS OF MOTE
Device on left hand side contains a microprocessor, temperature sensor, light sensor, 900 MHz radio, battery
On the right: a microprocessor, 4 sensors and laser pointer
Storage
Batteries ~1 J/mm3
Capacitors ~1J/mm3
Data stored in SRAM
Solar cells present for supply of power
Usage
Digital control :nw
Analog circuitry :nj/sample
Communication: nj/bit
Architecture
A single Smart Dust mote has:
a semiconductor laser diode and MEMS beam steering mirror for active optical transmission
a MEMS corner cube retro-reflector for passive optical transmission
an optical receiver
a signal processing and control circuitry
a power source based on thick-film batteries and solar cells.
Corner Cube Retro-reflector(CCR)
Comprises of three mutually perpendicular mirrors of gold-coated poly-silicon.
Has the property that any incident ray of light is reflected back to the source provided that it is incident within a certain range of angles centered about the cube’s body diagonal.
The micro-fabricated CCR includes an electrostatic actuator that can deflect one of the mirrors at kilohertz rates.
Thus the external light source can be transmitted back in the form of modulated signal at kilobits per second.
COMMUNICATION
2 methods
Passive communication
Active communication
COMPARISION OF ACTIVE AND PASSIVE TRANSMISSION
ACTIVE
semiconductor diode, collimating lens, beam steering micro mirror
Comparatively high power usage
Used only for short duration
Inter mote communication present
Long range ~ tens of km
Higher bit rates ~ few mbps
Base station commands & wake up the motes
PASSIVE
Uses corner cube retro reflector (CCR)
Low power consumption
Can be used for longer duration
Inter mote communication absent
Short range ~150 m
Lower bit rates ~ few kbps
Motes transmit periodic information automatically by CCR to base station
APPLICATIONS
MILITARY
Stealthy monitoring of hostile environments
Perimeter surveillance/ Locality Monitoring
Chemical or biological monitoring
Identification of friend or foe
CIVILIAN
Meteorological and geophysical monitoring
Monitor air conditions and room temperature.
Habitat monitoring (monitoring the behavior of animals in their natural habitat).
Factory and Process Automation.
A field application of smart dust
Monitoring onboard machinery
Purpose : predict machine failure
Implementation : 160 motes near ship’s pumps , compressors and engines
Motes looks for unusual vibrations or motion
Challenge: harsh machine environment
DRAWBACKS OF SMART DUST TECHNOLOGY
THE SIZE OF THESE DUST MOTES IS SO SMALL THAT ITS PRESENCE CANNOT BE DETECTED VISUALLY
IT MAY HINDER PRIVACY AND PEOPLE MIGHT ALWAYS BE AFRAID THAT SOMEONE IS MONITORING THEM
THE COST OF THESE MOTES IS QUITE HIGH
MOTES MAY ENTER RESPIRATORY ORGANS AND MAY CAUSE SERIOUS HEALTH TROUBLES
THE WIND BORNE MOTES ( MAPLE SEEDS) ARE EASILY BLOWN AWAY BY A STRONG GUST OF WIND SO THEY ARE KIND OF USE AND THROW ITEMS BUT THEY ARE CHEAPER.(ITS DEVELOPING TECHNOLOGY)
THERE IS A POSSIBILITY OF USED BY PEACE HATERS.
Future application of smart dust
Forest fire detection
Implementation : drop smartdust from an airplane
Motes self-organize into a network
Usage
A mote that detects a fire notifies central monitoring station
The mote’s location is the approximate location of the fire