According to their YouTube video:
"In this video we show how it is possible to perform gesture recognition just with contact microphones and transform every surface into an interactive board.
Through gesture recognition techniques we detect different kind of fingers-touch and associate them with different sounds.
In the video we used two different audio synthesis techniques:
1- physic modelling, which consists in generating the sound by simulating physical laws;
2- concatenative synthesis (audio mosaicing), in which the sound of the contact microphone is associated with its closest frame present in a sound database.
The system can recognise both fingers-touches and objects that emit a sound, such as the coin shown in the video."
