Patent ID: 6817130
Filing Date: 2004-11-16
Classification: F41A

Abstract:
In an unauthorized user prevention system for preventing unauthorized users from operating a particular device, said system comprising:an interlocking means for deactivating the particular device; a plurality of pressure sensors disposed at a gripping surface of the device for sensing a user's handgrip on the device; comparator means for comparing a pressure signature profile compiled from an output from said pressure sensors with at least one pressure signature profile in storage; control unit/cpu means for receiving an output from said comparator means indicating that the signature profile compiled by said comparator means matches said at least one pressure signature profile in storage; and wherein said control unit/cpu means releases said interlocking means upon receipt of a signal from said comparator means that the pressure signature profile of the user's handgrip on the particular device matches said at least one pressure signature profile in storage; The improvement, wherein said sensors comprise: two orthogonal sets of conductive lines and an intervening piezoresistive or piezoelectric layer being deposited upon said gripping surface, whereby the electrical path between a line of said first set and a line of said second set passes through the intervening piezoresistive or piezoelectric material where the two orthogonal lines cross to define at the crossing a sensor responsive to pressure applied against the gripping surface overlaying the crossing by changing the electrical conductivity or potential in the path including the two said crossing lines and intervening piezoresistive or piezoelectric material; the multiple crossings of said two orthoganal sets of lines defining an array of said sensors; and the signal outputs from the electrical paths including said sensors serving to define said pressure signature profile for a user of said device.