waving hands will charge your iPods, cell phones

Forget about plugging your iPod or BlackBerry into a power source ever again, for now you can charge these devices just by waving your hand, or stretching your arm, and even by taking a walk.

Scientists at Georgia have now come up with a new technology, called "nanogenerator", that converts mechanical energy from body movements or even the flow of blood in the body into electric energy.

And this electric energy can be used to power a broad range of electronic devices without using batteries. "This research will have a major impact on defense technology, environmental monitoring, biomedical sciences and even personal electronics," said lead researcher Zhong Lin Wang, Regents' Professor, School of Material Science and Engineering at the Georgia Institute of Technology.

The new "nanogenerator" could have countless applications, among them a way to run electronic devices used by the military when troops are far in the field. The researchers have described how it's possible to harvest energy from the environment by converting low-frequency vibrations, like simple body movements, the beating of the heart or movement of the wind, into electricity, using zinc oxide (ZnO) nanowires that conduct the electricity.

The ZnO nanowires are piezoelectric - they generate an electric current when subjected to mechanical stress. The diameter and length of the wire are 1/5,000th and 1/25th the diameter of a human hair.

The process of generating energy from movement made the researchers to conclude that it was most effective to develop a method that worked at low frequencies and was based on flexible materials. The ZnO nanowires met these requirements.

Also, Wang said that a real advantage of the technology was that the nanowires could be grown easily on a wide variety of surfaces, like metals, ceramics, polymers, clothing and even tents. And the nanogenerators could operate in the air or in liquids once properly packaged.
"Quite simply, this technology can be used to generate energy under any circumstances as long as there is movement," said Wang.

The nanogenerator would be particularly critical to troops in the field, where they are far from energy sources and need to use sensors or communication devices. Wang also said that having a sensor, which doesn't need batteries, could be extremely useful to the military and police sampling air for potential bioterrorism attacks in the United States.

Although biosensors have been miniaturized and can be implanted under the skin, he points out that such devices still require batteries, and the new nanogenerator would offer much more flexibility.

A major advantage of the new technology is that many nanogenerators can produce electricity continuously and simultaneously.

WHAT IS BLUETOOTH TECHNOLOGY ?

Bluetooth, named after the renowned Danish King, Harold Bluetooth, is a short-range wireless connectivity standard.

Bluetooth is capturing the minds of the present day technologists, as a technology enabler for the wireless unification of a wide variety of portable devices like mobile PCs, mobile phones and the like. It does away with the cables and enables voice and data transfer between the devices through wireless networks called piconets.

The primary segments identified for Bluetooth application are: Cellular & PCS Mobile Phones, Digital Cordless Phones, Data Access Points, PC Cards and Adapters , Notebook & Desktop PCs, Handheld PCs & Palm Companions / PDA s, Digital Still Cameras, Output Equipment, Automotive and Industrial & Medical applications.

The technology behind it:
Bluetooth is a Radio Frequency (RF) specification for short-range, point-to-multi-point voice and data transfer. An advantage of Bluetooth is it's similarity to many other specifications already deployed and it's borrowing of many a feature from these specifications. The 2.4GHz band is used by IEEE 802.11 to enable wireless LAN connectivity. Bluetooth borrows specifications to enable file sharing and data transfers between devices from IrDA (a wireless specification that uses InfraRed light to connect devices). HomeRF SWAP, a specification aimed at small network of devices for the home environment, is another source for Bluetooth.
It is omni-directional and has a present nominal link range of 10cm to 10m, which can be extended to 100m, with increased transmitting power. Bluetooth operates in the 2.4GHz Industrial-Scientific-Medical (ISM) Band and uses a Frequency Hop (FH) spread spectrum technology in which packets are transmitted in defined time slots on defined frequencies. A full duplex information interchange rate of upto 1Mbps may be achieved in which a Time-Division Duplex (TDD) scheme is used.

A Bluetooth System:
* A Radio Unit - consisting of a radio transceiver, which provides the radio, link between the Bluetooth devices.
* A Baseband Unit - a hardware consisting of flash memory and a CPU. This interfaces with the radio unit and the host device electronics.
* Link Management Software - a driver software or firmware which enables the application software to interface with the baseband unit.

* An Application Software - this implements the user interface and is the application that can run on wireless.