presence detector for enclosed cases containing aerosol sprays - uses epoxy board sliding under case and detecting self inductance on printed spiral patterns matching base section of cans

摘要

The device uses inductive sensors, which are each coupled to a self inductance detection circuit. One or more printed circuit boards are in sliding contact with the box. Each PCB comprises several printed spiral circuits which are designed as a function of the shape and dimensions of the metallic part of the objects. The central ends of these spiral circuits are connected by bridges to external connecting strips in order to form the inductive sensors. The output from the spiral circuit is fed to a logic unit, which also receives information on the speed of the aerosol conveyor.