And there is the piezoelectric effect, which is where most attention now to go out, because it is a

A system as large as a large pin sensor nodes can be a life-powered hose. The device of scientists at the University of Michigan converts vibrations in the environment efficiently into electricity. Handy for a wireless sensor network in a factory!
"Energy harvesting" (energy harvesting), as it is also known as your energy from the environment around you power your own devices. Widely bushey park you think of wind or water mills and solar panels, but on a small scale can also. Indeed, on a small scale, it is particularly interesting, bushey park as you suggest many devices no longer need batteries. And then "wireless" - as in a wireless sensor network bushey park and Wireless Sensor Network (WSN) - truly wireless.
Researchers at the University of Michigan have now created an energy harvester. At very small scale Their system is only 27 cubic millimeters! The energy it can harvest is vibrational energy: it can in the area to convert the vibrations into electricity.
There are various ways of setting energy to convert to electricity. So you can make use of the thermoelectric effect (cooling systems), the photovoltaic effect (solar cell) or electromagnetic induction (tablet).
And there is the piezoelectric effect, which is where most attention now to go out, because it is an efficient conversion and it can be easily achieved on a small scale. The scientists in Michigan use this effect.
The piezoelectric effect means that a picture of special material produces voltage when it deforms, bushey park for example, by pressing. Usually, such a picture used as a cantilever, it is a kind of diving board attached to the object to vibrate. If the object vibrates, the "diving board" vibrates and if there is tension produced.
The "diving board" is attached to the vibrating object (left). bushey park At the end is a weight for extra far to bend. On top is a layer of piezoelectric material that generates voltage to sag. Hajati and Kim, 2009 PowerMEMS
You can enhance the effect meetril by ensuring resonance. That is, the "diving board" vibrates harder (and thus generating more tension) when the object vibrates at a certain frequency. Which frequencies that are, depending on the material and the type of diving board. For example, some systems work well at high frequencies bushey park and others are low. If a battery
The special feature of the system is that it works in Michigan many different frequencies. The "base rate" is 155 Hertz and the band width is 14 hertz, which means that it produces stress at all vibrations between 148 and 162 Hertz. That's about the type of vibration that you feel when you put your hand on a working microwave.
The amount of stress depends not only on the frequency but also the amplitude of the vibration, or how hard sweeps down the diving board? At an amplitude of 1.5 g (1.5 times the acceleration of gravity), the system already delivers more than 200 microwatts (one microwatt is a millionth of a watt). An integrated circuit is 1.85 volts from here: similar to the voltage that provides a rechargeable battery.
With this performance the device is about five to ten times more efficient than other systems, while it is still so small. "We managed to make it more energy output (for a given input) than any other device on the market in a very small space system" said Khalil Najafi, one of the researchers. Factory
The system is primarily intended for in factories, where a lot of demand for wireless sensor networks. The network of sensors keep an eye on all the machines and can warn on time faults. However, energy is a major obstacle to a large network.
"Up to 80% of the total cost of a wireless sensor network is to install and maintain the power and continuous checking, testing and replacing batteries," said Erkan Aktakka, also a member of the research team. "The use of" existing bushey park energy "would be a good solution." He is referring to the many vibrations in the factory, which you can use for the sensors. Using the new harvester
Sources Harb, "Energy harvesting: State-of-the-art, Renewable Energy bushey park (2010), bushey park doi: 10.1016/j.renene.2010.06.014 Beeby et al," Energy harvesting vibration sources for microsystems applications, "Measurement Science and Technology, 17 (12), Art. No. R01 pp. R175-R195, 2006, doi: 10.1088/0957-0233/17/12/R01 Read more about batteries and sensornetwer