Disclosed is an inventory control system or parking space detector including an inductive loop technology that is either embedded in the concrete or located atop the concrete, or any other feasible method of setting an inductive loop. By monitoring the change in inductance of the magnetic field that is generated by the loop as cars of various sizes and weights enter the looped area, a determination of whether or not the inventory is controlled or the parking spaces are all full is made when the inductance value reaches a certain predetermined level. This predetermined level will be determined by calibration in the initial installation in order to determine the exact inductance values when a group of parking spaces are full.