A pivot rod connection interface cover for covering the connection interface of a sun visor pivot rod which protects occupants from head impact injury in the event of a crash, yet allows the sun visor to both pivot and rotate in a fully normal and familiar manner. The number of small particles in the suspension is counted. The measured data is transferred to a base station computer 3 and stored in a database 100 inside the base station computer 3. A sliding carriage is movably connected to the rod. The access control action may include allowing the node to access a virtual local area network in the network environment, denying access to the network environment, etc.