Racket with piezoelectric strings

A system comprising a racket having a handle, a frame attached to the handle, and strings comprising at least two perpendicular strings stretched in the frame, each string running back and forth in the frame through openings formed therein, wherein the system comprises:

• for each string, a piezoelectric sheath coating said string along most of its length, said sheath being divided along its length into at least three piezoelectric areas, each comprising a piezoelectric layer interposed between two conductive layers respectively forming a first and a second electrodes, the piezoelectric layer and at least one of the electrodes of each piezoelectric area forming an assembly electrically insulated from the piezoelectric layers and the electrodes of the other piezoelectric layers so that each piezoelectric area generates between its electrodes an independent voltage according to mechanical stress exerted on the strings;
• and
• an electronic circuit connected to the piezoelectric areas of the strings to identify a portion of the strings submitted to the highest mechanical stress according to the voltages generated by the piezoelectric areas of the strings.