A team of researchers from the University of Washington conducted a successful test of a device,which can transfer the text message without using any power sources. The technology uses the energy dissipated in the air, which will convert a signals available wireless networks in the desired signal.
The experiments were carried out in the field at different distances from the TV tower in the range from 800 m to 10.4 km, and in various conditions of building: in an apartment building or on the corner. For data were taken two antenna device whose size is comparable to credit cards, located at a distance of 76 cm from each other (outside the experiment) and 46 cm (testing inside a building). Researchers have been able to achieve a data rate of 1 kbit / s.
The practical application of such a system is possible now. If the data rate for voice still not enough, send text messages user can, if the battery runs completely. Such a solution would help create truly wireless devices that are not attached to a power source. Can, example, to equip all high-rise buildings and bridges a sensors, that will monitor the integrity of the structure. They will have a small size and run forever.