Sound Recovery From Radio Signals

With the proliferation of smart devices, voice interfaces have become an integral part of our lives, which typically senses sound by microphones through converting the changes in air pressure into electrical signals. Sound sensing through another modality can enable various sensing applications in the absence of a microphone. In fact, environmental sound creates tiny vibrations on object surfaces, which could be captured by radio signals. In this work, we model the vibration on object surfaces due to sound for mmWave devices. We propose a method for the recovery of sound and conduct experiments with various materials to investigate the feasibility of sound reconstruction. We further evaluate the effect of distance and placement to understand the practical limits on the sound reconstruction. The results show that, by using a commodity off-the-shelf radar, it is possible to capture a significant amount of sound from the environment.