| abstract |
A pressure sensing mat utilizes a thin sheet of semiconductor material that has an electrical conductivity generally invariable as to pressure applied to the mat material. The sheet of semiconductor material is sandwiched between sheets of copper, steel or aluminum foil which are in mechanical contact with the semiconductor sheet to define a pair of electrodes. The electrodes are connected to various circuits including a pressure (voltage) threshold detector, a learning circuit for establishing a learned threshold, a circuit for matching time-pressure patterns and a circuit for detecting pressures between a predetermined maximum and minimum level. A matrix of pressure sensing mats is utilized with various circuits to detect sequential pressure patterns. |