Sensor Networks

I attended an interesting session on sensor network. It was organized by Institute of Engineers.

The topic was “Experiences, strategies and challenges in building wireless sensor network”. 

Speaker: Dr. S.S. Inynger [email protected] Chairman / Roy Paul Daniels Professor of Computer Science, Louisiana State University

First of all he emphasized with some references that Bangalore is the best city for R&D and IT industry compare to US.

His team has started research on this topic since 1991. Nowadays sensor network, ZigBee has become buzzwords. Ember is pioneer company in this field. We have already seen networks of sensors like smoke detectors/heat detectors.

Architecture:

Basic architecture is distributed sensors provide information to sink. Sink can be connected via Internet to Task Manager. There are large numbers of sensors also called MOTE, form a pure random wireless network without any topology. We can have biomedical sensors too. It is a dynamic, scalable, ad-hoc network of self configurable, self healing sensors with multi hop adaptive routing.

Specifications:

Maximum size of sensor is 2”, minimum as small as dust particle.

Range of communication 10ft to 100ft.

Battery life: 2 hours

CPU clock frequency: 125 MHz

RAM: 4kb to 10kb

Cost: $10 to $40. Low cost. So they are throw away sensors

It has interrupt routine, its own Operating System. In one application memory is divided in 3.5kb routing table/algorithm and 4.5kb for application.

One sensor is a programmable device. It consists of sensing element, battery, processor, memory and communication circuit.

Applications:

Medical application to monitor parameters inside the body

Object tracking

Environment monitoring

MEMS = Micro Electro-Mechanical System

Monitor migration of birds

Forest wild-land fire management system

Home care system

Military applications

To track terrorist

US government is using it to find out Osama Bin Laden 

Challenges:

Major challenge is extend battery life. The sensors go to sleep mode whenever needed. It is also vulnerable to virus/warm attack. Here virus tries to generate dummy data to drain the battery. As per Murphy’s  law, the sensor stops working exactly at the moment, when the monitored object is nearby :) There are many redundant data to be filtered out. The measured value is not accurate. It does not provide deterministic value of monitored parameter.

At last it was an interactive question answer session also. Audience also asked about why US government fails to locate Osama Bin Laden and why Indian government fails to locate Virappan?

Note: I have just described my experience about this session. I tried my best, yet the information presented here may be incorrect. There is not any motive to promote any technology, brand name or institute. .