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Current issue

ELEKTRO 3/2019 was released on March 11th 2019. Its digital version will be available on March 11th 2019.

Topic: Amper 2019 – 271 International trade fair for electrical engineering

Main Article
Smart Cities (part 8)

SVĚTLO (Light) 2/2019 was released on March 15th 2019. Its digital version will be available immediately.

Architectural and scenic lighting
The architectural lighting of Bečov nad Teplou castle
Lighting design in a nutshell – Part 41
The analyse of light picture a little more theoretic

Day light
Biggest mistakes in day lighting design of buildings

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-