Abstract: Triboelectric sensors which generate electrical signals in response to mechanical disturbances creating relative motion of conducting and dielectric components of the sensor are fabricated from thin metal foil which is plastic-coated on one side and which can be formed into elongated, cable-like sensors having a variety of other shapes and sizes. The foil encloses one or more wire-like inner electrical conductors which, may be sealed within the envelope formed by the outer foil by heat-sealing the plastic-coated foil. A technique similar to welding may be used in which electrodes are placed in contact with opposing faces of the metal foil and an electrical current is passed though the foil. Local heating of the foil and of the plastic coating near the point of contact of one or both electrodes can cause the plastic to melt and the opposing plastic faces to bond together.

Abstract: A system is described for the automatic detection of ball bounces on a tennis court, and which is applicable to similar games. The system comprises a sonar-like sound system in conjunction with a pressure-sensitive system located on the court surface itself. The sound system uses a multiplicity of microphones to detect and means to analyze the sounds and to calculate the position of sounds identified as balls striking the court surface. The pressure system is used to detect ball bounces on the boundary lines themselves, and utilizes coaxial cables as the sensing elements. The pressure system is checked only when the sound system determines that a ball is bouncing on or near one of the boundary lines. Processing is done by a personal computer to which a special interface card is added.