US Patent 7843339 Secure point of sale device employing capacitive sensors

A point of sale device including a housing, a protected enclosure located within the housing, information storage functionality located within the protected enclosure and storing information to be protected information, a capacitance sensor based security system including at least one capacitance sensor operative to sense the capacitance of at least one of at least part of the housing and at least part of the protected enclosure at a reference time and thereafter and to provide an alarm indication of at least a predetermined change in the capacitance sensed by the at least one capacitance sensor.