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Current issue

ELEKTRO 2/2019 was released on February 13th 2019. Its digital version will be available on March 11th 2019.

Topic: Electrical appliances – switching, protective, signalling and special

Main Article
Advanced power converter topology
Smart Cities (part 7)

SVĚTLO (Light) 1/2019 was released on February 4th 2019. Its digital version will be available on March 5th 2019.

Fairs and exhibitions
Invitation at LIGHT IN ARCHITECTURE exhibition
Prolight + Sound 2019: keep up with time
The light at For Arch 2018 fair

Public lighting
Lights of towns and communities 2018 – the meeting at the round table

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-