The first cellular phone without battery

Researchers in the US presented their first mobile phone, which consumes so little energy that no battery is needed. Although it is an experimental device, with many possibilities, it is considered a first step in the future exemption from the burden of charging.

The phone only needs 3.5 microbatts to operate, which it receives either from radio signals emitted by a base station up to ten meters or from ambient light using a built-in microscope solar cell, the size of one grain of rice. Computer scientists and computer engineers at the University of Washington, headed by Deputy Professor Shyam Gollakota, have made, besidesnormal calls also Skype calls with their battery-free phone.

The researchers’ main trick was that they abolished a highly energy-intensive feature of most mobile phones: converting analog audio signals into digital data the device can “understand”. Instead, the new phone exploits subtle vibrations on its microphone or speaker whenever the user speaks or hears a call.

The device uses these vibrations to encode the speech on the radio signal. The researchers said that new technology could be widely used in the future. In the meantime, they will try to improve the device’s range and encrypt its conversations to make it safer. They will also try to add extra features to the battery-free phone, such as a monitor and streaming video.