First battery-free mobile phone that uses almost no power

Able to make Skype calls

During testing, the team was able to make a number of Skype calls on the handset made of commercial, off-the-shelf components that can receive and transmit speech and communicate with a base station.

“We’ve built what we believe is the first functioning cellphone that consumes almost zero power,” said co-author of the paper, Shyam Gollakota.

“To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed.”

To solve this 21st century problem, the UW team realised that the greatest consumer of power in a smartphone is when it converts analogue signals that convey sound into digital data that a phone can understand.

To get around this, the team connected an antenna to components of the phone linked to its microphone and speaker.

As a person speaks, the tiny vibrations in the microphone or speaker generates enough ambient energy to convert motion into changes in standard analogue radio signal emitted by a telecoms base station.

Source: Silicon Republic