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Current issue

ELEKTRO 8-9/2018 was released on September 4th 2018. Its digital version will be available immediately.

Topic: Electrical engineering in industry; 60th International Engineering Fair in Brno

Main Article
Smart Cities (part 3 – volume 2)

SVĚTLO (Light) 5/2018 was released on September 17th 2018. Its digital version will be available immediately.

Interiors lighting
Luminaire selection by the concept of interior
The unique book about interiors nowadays on market
Invitation on colloquium Interiéry 2018 – exceptional action for the seventh time

Newsreel
Profesor Jiří Habel passed away – memories remain

First battery-free cellphone

10.07.2017 | University of Washington | www.washington.edu

University of Washington researchers have invented a cellphone that requires no batteries — a major leap forward in moving beyond chargers, cords and dying phones. Instead, the phone harvests the few microwatts of power it requires from either ambient radio signals or light.

The team also made Skype calls using its battery-free phone, demonstrating that the prototype made of commercial, off-the-shelf components can receive and transmit speech and communicate with a base station.

First battery-free cellphone

The team of UW computer scientists and electrical engineers eliminated a power-hungry step in most modern cellular transmissions — converting analog signals that convey sound into digital data that a phone can understand. This process consumes so much energy that it’s been impossible to design a phone that can rely on ambient power sources. Instead, the battery-free cellphone takes advantage of tiny vibrations in a phone’s microphone or speaker that occur when a person is talking into a phone or listening to a call.

An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power.

Read more at University of Washington

Image Credit: Mark Stone/University of Washington

-jk-