A modular system for connecting attachments to the extension arm of a construction machine, wherein each module has a standardized coupling arrangement. The method includes forming a plurality of barrier ribs on an insulating substrate and forming a plurality of grooves partitioned by the barrier ribs. A rear member is mounted to an inner side of the body. A layer of fluid pathways is defined by two opposing charged film layers at least one of which is a structured film layer. This signal or change in signal is monitored by the communication device.