| Twenty four hours a day, year-in, year-out, doctor | | | | before going to sleep again. A programmer writes |
| Flemming wants to monitor the heart rate and blood | | | | software to control the mote and make it perform a |
| oxygen of a patient working in a factory at minimum | | | | certain way. |
| cost in real time. Scientist Galvin was given the task of | | | | Deployment: |
| monitoring in real time two dozen variables in a very | | | | The motes are usually required to be deployed in 100's |
| hostile environ around the clock over wide area in all | | | | to millions with embedded sensors forming a |
| three dimensions. This hostile environ could be a battle | | | | self-organising sensor network despite limited |
| field scenario or uninhabited glacier of Himalayas. | | | | processing power, storage, energy and bandwidth. |
| There are myriad such vexed complex problems, | | | | There is no limit on type of sensors. Imagine any type |
| given a chance, which scientists wants to explore | | | | of sensor from temperature, light, sound, position, |
| ceaselessly. It is endless list of problems like | | | | acceleration, vibration, stress, weight, pressure and so |
| ecosystems, habitat of animals/birds, soil-biodiversity, | | | | on. The computer in the mote connects to the outside |
| nutrient cycling, climatology, flooding, traffic control, | | | | world with a radio link with transmitting range of about |
| pollution and so on. We cannot solve complex | | | | 5-100 m. Motes are packed in tiny size boxes of size |
| problems with limited data. To illustrate, soil is the most | | | | not exceeding 5 mm. Current cost of the motes on |
| complex layer in the chain of ecosystem, but it is | | | | average is about 25 US $ and likely to fall down with |
| poorly understood due to limited data collected by | | | | time. |
| technicians through selective sampling for analysis in | | | | Challenges: |
| the laboratory. Is there a methodology to monitor such | | | | Design, development and deployment include network |
| global phenomena ? Thanks to our scientists, the | | | | discovery, control routing, information processing, |
| solution is in sight. | | | | querying and security, creating a sensor web for |
| Today, we have tiny computers packed in a box size | | | | scientific applications requires extensive customization, |
| of just few millimeters called 'motes' or 'smart dust'. | | | | new standards, dedicated operating system, |
| They have the ability to monitor data continuously in | | | | programming and user friendly web tools. To cut down |
| real time of the physical world on a large scale over | | | | costs one needs to look into commercial adoption and |
| large sample-population over large geography. Some | | | | networking on a larger scale, which is slowing the |
| call this tiny stuff 'motes', others call it 'smart dust'. | | | | speed by several years. |
| Basically motes are building-blocks of wireless sensor | | | | The future: |
| network. Why 'Smart dust'? The name smart dust | | | | Wireless sensor network have been identified as one |
| was coined by Pister, University of California, Berkely | | | | of the most important upcoming technologies in the |
| to describe his version of sensors joined in network in | | | | 21st Century. Wireless sensor network is going to |
| 1000's or even millions to comprehend a physical | | | | revolutionize many physical field scenarios by making |
| scenario as though it is observed by a human brain. | | | | large scale measurements possible at temporal and |
| The core of a mote is a small low cost low power | | | | spatial dimensions. There are myriad ways that motes |
| computer. A typical mote uses an 8-bit | | | | might be used and as people appreciate the concept, |
| micro-computer that has 512 Kbytes of on board flash | | | | the application scope will be even more. It is opening up |
| memory running at 4 MHz. The CPU usually matches | | | | a fascinating new field of distributed sensing which is |
| with 8088 CPU of IBM PC with 10 bits A to D | | | | far beyond the scope of present day knowledge. The |
| converter. It is designed to consume just 8 milli amp in | | | | diverse application in the future include agricultural |
| working and 15 micro amp while in sleep. It can have | | | | management, complex structures and earth quake |
| operation life of nearly 150 hrs with two AA batteries. | | | | monitoring, industrial controls, military applications, |
| To consume power, it is made to sleep for 10 secs | | | | transportation, shipping, fire-fighting and |
| and wake up and give status for few microsecond | | | | home-automation and many more - all at global scale. |