US Patent 9244133 Handheld devices and structures to detect sticky devices having magnets

Apparatus and methods for detecting concealed personal security threats may comprise conventional mirrors and less conventional arrays of Hall-effect sensors and/or magnetometers, preferably at least two axis or three axis sensors or sensors mounted back-to-back. The concealed personal security threats may comprise, for example, sticky devices consisting of geographic position sensors for covertly broadcasting motor vehicle location data, of so-called Improvised Explosive Devices (IED's) which may be covertly or openly affixed to, for example, the undercarriages of motor vehicles using strong magnets and later exploded, the former giving away private location information, the latter causing damage to the motor vehicles to which they are affixed and sticky containers for hiding contraband among other “sticky devices.” Magnetic fields detected by, for example, arrays of Hall-effect sensors and the like may be quantified and stored in processor memory as a vehicle magnetic field signature. A processor receiving magnetic field data collected by the arrays may retrieve and subtract known signatures from acquired magnetic field data for a given vehicle to obtain location for a magnetic field on the vehicle that may be of potential interest as a risk.