Demo: The RFID Can Hear Your Music Play

In this work, we devise RF-DJ, a contactless music recognition system with the help of COTS RFID device. Since the music is caused by vibration and the vibration can influence the RF signal, our system could accurately recover the frequency of every tone, especially string instruments. Specifically, RF-DJ is immune to noises from the player/instrument motions and the ambient environment. Further more, it can recover the high frequency signal from the relatively low sampling rate data. In our demonstration, we put one tag on the surface of ukulele (not the string) and achieve the overall recognition accuracy of $93%, 90%, 87%, 81%$ when using 1,2,3,4 strings, respectively. Compared to typical machine learning based RF sensing systems, our system is model driven instead of data driven, which requires little training effort and could be applicable across different locations. Last but not the least, our system can also be used for other instruments such as zither, violin and kalimba and shows similarly good performances.