Little Powerful Device: Smart Dusts
EE453 Project Report submitted by
Cheng Li Yang Fall 2008
Can you imagine the size of a grain of dust or mote? Obviously they are really small object that it’s impossible to see it with naked eyes. However, thanks to the tremendous development of nanotechnology, a device with the size of dust has been developed and introduced by the scientists. They call this particular particle “Smart Dust”. Smart Dust device is a very tiny wireless micro-electromechanical sensor (MEMES) that able to detect many of things such as light, humanity, temperature and vibration and so on. Each of them contains sensors, computation, bidirectional wireless communication technology and power .The dust is able to collect many data, run the computation and communication through two –way band radio between dusts in the distance range about 1000 feet. (“[1]”). Today, Smart dust has been widely used for military and other different areas.
In 1998 Fr. Kris Pister of the UC Berkeley conceived the idea of smart dust.(“[5]”) He tried to build a device with a small computer, sensor, and communication device integrated into a single package. The Defense Advanced Research Projects Agency (DARRA) funded the project and gave him a goal that such device is able to be integrated into a cubic millimeter package. To build such small motes, there was an issue raised by the UC Berkeley team which was how to power the device. Using small battery can minimize the size of the mote; however, it only could store less energy; Using large battery, then the size of mote would become larger. To meet with both criteria of long battery life and miniaturization, they tried to come up a way to save the energy to achieve the longer battery life. Dr. David Culler finally design a program that enable the motes to “sleep” most of the time yet “wake up” regularly to take readings and communicate.(“[6]”). The other issue that team face is the optical communication system. A mote with a passive communication system (PCS) does not have an “onboard light source” but instead it uses a series of mirrors controlled by a small electrical charge (“[7]”). So the mode is able to adjust the position of its mirror to send the data in the form of pulse of light which read by the optical sensor when there is a laser pointing it. The PCS ensure the possibility in reducing the power consumption, but it still had some limitation because of indirectly behavior of the mote in the network. (“[8]”). The last issue was how to create a small operation system to the mote; with the intelligence knowledge from the teams and Dr. David Culler at UC Berkeley, they created software that able to be responsible for operating the motes, run communication with others, and managing the energy consumption (“[8]”) the whole structure of the smart device is shown below:
Figure1
Before looking at the application of the smart dust, we should first understand how the smart dust works. The smart dust has many individual self-contained, tiny sensor, communication platforms for the complex sensor network. Sensor is device that able to measure the quantity and convert it to a signal. There are so many kinds of sensor in the industry, such as thermal sensor, optical sensor, electrical sensor and mechanical sensor etc. For the smart dust, it’s being integrated with different sensor based on the particular application to be used. The smart dust is able to be operated by a microcontroller to control the power to the different components of the system to save energy. The smart dust has optical sensor that able to detect the people who want to communicate with it. The communication contains the message that associated with other smart dust. To response the communicated information, the u-controller use a kind of laser called corner cube laser to send the date to the other dusts. The dusts can be operated by itself to choose either receive or send transmitting data. (“[2]”). Based on the connection between dust and dust, it creates a smart dust network also called “motes”. The mote concept generates a fresh method of thinking about computer. The core of a mote is little low power computer. The computer is able to monitor one or more sensor. The computer connects to the outside world with a radio link. In general the radio links can let motes to transmit the data in the range of distance at 10 to 200 feet. The longer the distance, the higher the cost, size and power consumption. The package of the motes is as small as size of quarter. In the future, the motes are even fit into a few millimeters on a side. (“[3]”)
Photo courtesy Crossbow Technology, Inc.
The above picture is the MICA2DOT mote,
and it powered by a very tiny battery, the size
of the mode is as same as quarter.
There are several application that used by the smart dust technology. For the early application, the smart dust was used to track the lost vehicle if they entered into an isolated desert area. When the motes had been dropped by an unmanned airplane, it started to track the moving vehicle, when the motes gather the information from and it would be saved for the records. The UAV plane then collected the data from the motes to find out the location of the lost vehicle.(“[10]” ) Today, the smart dust has been used for the military. It also became the new secret weapon in Iraq .The military crop the dust to the enemy lines, and tracking the enemy monitored by the integrated tiny sensor in the dust. Similar to the grain size tracking device such RFID, EZ pass, the smart dust can be given a unique serial number that, when hit with “interrogation signal” from troops on the ground, or aircraft overhead, is broadcast back. So people believed that the smart dust play a very important role in the death of al Qaeda leader Abu Musab al Zarqawi. (“[11]”)
Now there is group of people working on an application of “Smart Dust” for Pavement Condition Monitoring. Their idea is inject a proper algorithm into “Smart dust processor. Then based on the measurements collected the smarts dust, the device is able to classify pavement surface in three conditions: dry, wet and icy. (“[12]”).
Another group of researchers at the UCSD have developed a kind of smart dust that capable of detecting bioterrorist and chemical agents. When the dust recognizes the kinds of biological and chemical agents, the information can be read into a sequence of bar codes by a laser. The bar code on the smart dust is a specific wavelength of the light that is reflected from the surface after thin films layered on the silicon chip chemically react to a specific chemical or biological agent. (“[14]”). They use the silicon wafer to encode the bar code by generate a layer of nanometer-thick porous film on the wafers. Then ultrasound has been applied to break apart the wafer to create the layered structure with the particle. Then the particle can reflect the color in very accurate, and each of them can be viewed as single bar.
In the modern world, since the smart dust is so powerful and small, there are couples other applications that may be use the dust. By the features of the dust, we can use it to save the energy (=cost). People often do not know why their power bills are so experience. The reason behind this is that most of them often forget to turn off the light when they go out, forget to adjust up the air conditioner while they go sleep. With the help by the smart dust which has the function to detect if the room is empty or occupied as well as the level of the light and temperature, then the motes would provide data to the microcontroller which able to turn off the light by itself and making adjustment on the temperature. Since the smart dust has integrated sensor inside, they can use to detect the temperature for that. That would really save the energy and even save the money for the people. “We think on air conditioning costs, motes could save20 percent on electrical bills and they’re 50 percent to 80 percent cheaper to install than wired sensors” said by Mike Horton, CEO of Crossbow. (“[13]”)
Word Cited
[1] Thomas Hoffman “Smart Dust, Might notes for medicine, manufacturing, the military and more.” March 24,2003
http://www.computerworld.com/mobiletopics/mobile/story/0,10801,79572,00.html
[2] “Top Secret: Myth and Reality in Espionage: Smart Dust”. 2005
http://www.facstaff.bucknell.edu/mvigeant/univ270_05/EmilyBeeing/Methods.html
[3] Brain, Marshall. "How Motes Work." 28 February 2004. HowStuffWorks.com. http://computer.howstuffworks.com/mote.htm
[4] “Smart Dust Stalked Zarqawi” June 10, 2006
http://www.strategypage.com/htmw/htecm/articles/20060610.aspx
[5] V.S. Hsu, J.M. Kahn, & K.S.J. Pister “Wireless Communications for Smart Dust” Jan. 30, 1998
http://robotics.eecs.berkeley.edu/~pister/publications/1998/smartdust_comm_memo.pdf
[6] Karen F. Schmidt “Smart dust' is way cool” Feb. 16, 2004
http://www.usnews.com/usnews/tech/articles/040216/16dust_2.htm
[7] Pister,K.S.J (2001), “Smart Dust: communication with a Cubic Millimeter Computer” Jan2001
[8] Takahashi, D “Dusting for Data: ‘Smart Dust’ Sensors Monitor Everything from Oil Tankers to Bird Habitats,
http://www.mercurynews.com/mld/mercurynews/business/technology/9770734.htm
[10] Jason Lester Hill “System Architecture for Wireless Sensor Networks”
http://www.jlhlabs.com/jhill_cs/jhill_thesis.pdf
[11] “Smart Dust Stalked Zarqawi” June 10, 2006
http://www.strategypage.com/htmw/htecm/articles/20060610.aspx
[12] “An Application of “Smart Dust” for Pavement Condition Monitoring” 2006
http://www.richardivey.com/SPIE2006_SmartDust_Final_Version.pdf
[14] Kim A. McDonald “"Smart Dust" Capable of Detecting Bioterrorist and Chemical Agents” September 3, 2002
http://www.universityofcalifornia.edu/news/article/4688
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