A group of researchers from the University of Washington (UW) created a mobile phone that runs without a battery and also, among the different tests that have been done with the device, the team made Skype calls, which shows that the prototype Made of available commercial components can receive and transmit voice and communicate with a base station.
The new technology is detailed in an article published July 1 in Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies. “We have built what we believe is the first mobile phone to consume almost zero power”, Co-author Shyam Gollakota, an associate professor at the Paul G. Allen School of Computer Science and Engineering at UW, said in a statement.
To achieve the extremely low power consumption it needs to run a handset through the collection of energy from the environment, you had to rethink the way these devices are designed. UW’s team of scientists and electrical engineers removed a step of high energy need in most modern cellular transmissions, that of converting analog signals that transmit the sound to digital data that a phone can understand. This process consumes so much energy that it has been impossible to design a phone that can rely on environmental power sources.
On the other hand, the mobile phone without battery takes advantage of the small vibrations in the microphone or the speaker that occur when a person is talking on a telephone or listening to a call. An antenna connected to these components converts that motion into changes in the standard analog radio signal emitted by a cellular base station. This process encodes essentially the speech patterns in the reflected radio signals in a way that uses almost no energy. To transmit voice, the phone uses vibrations from the device’s microphone to encode voice patterns on the reflected signals. To receive voice, it converts radio signals encoded into sound vibrations that are captured by the speaker of the phone. In the prototype device, the user presses a button to switch between these two modes of transmission and listening.
The phone without battery still requires a small amount of energy to perform some operations. The prototype has a power budget of 3.5 microwatts. Researchers at the University of Washington demonstrated how to collect this small amount of energy from two different sources. In one case, the battery less phone prototype can operate with the energy of ambient radio signals transmitted by a base station up to 10 meters away. In the other, using the energy collected from ambient light with a tiny solar cell, about the size of a grain of rice, the device was able to communicate with a base station that was more than 15 meters away.
This model is made from a series of commercial electronic components already available in the market that can give rise to the development of a new technology so that, in the future, the use of conventional batteries will be definitively eliminated.