Directional human approach and touch detection for nets based on capacitive measurement

In a volleyball game, touching the net represents a foul under circumstances defined by the game rules. Currently, a referee decides if the net was touched or not. In order to avoid wrong referee´s decisions, a system is desirable, that automatically detects a net touch and also indicates the offending party. We propose a system based on electrical capacitance measurement that detects both approximation to and touching of the net. A player causes characteristic changes of the electrical capacitance between conductive structures (e.g. wires or nets) within the game net and conductive structures within or on top of the court floor. As the dielectric properties of a volleyball and a human differ significantly, the two scenarios can be distinguished. Finite element simulation, preliminary measurements with a laboratory test setup and measurements with a real-world setup using a standard volleyball net are presented.