Dennis Siegel (Dennis Siegel) — German university student became famous this year, finishing second at the technological competition in the University of the Arts Bremen. He presented the invention, which can charge the battery, capturing electromagnetic fields, the similarity of those that generate Wi-Fi device.
In fact, to charge AA batteries he needed a day.
Siegel explains the operation of the device in his blog:
The presence of the electromagnetic fields due to the presence of a simple electric current. We are constantly surrounded by electromagnetic fields that we create for the transmission of information or as a by-product. Many of these fields is very intensive and can be assembled with high frequency coils and diodes. So I created a device that can produce energy from certain types of fields and store it in a conventional battery. This way you can get unlimited energy source such as a coffee machine or a cell phone, simply by placing in an electromagnetic field collector with LED-indicator at the top.
Depending on the strength of the field device can charge a small battery for one day. To date, two types of collectors created for different types of fields: small for low frequencies below 100 Hz, typical for residential networks (50/60 Hz) and a larger, more suitable for low and high frequencies like radio (around 100 MHz) networks, GSM (900/1800 MHz), Bluetooth, and WLAN (2.4 GHz).