Doubly interlaced sensor array and method to support low power counting and identification

Abstract

Systems and methods for providing low-power sensing, identification, and sweep detection for items on a sensor mat are provided. Item detection sensors are provided in grid on a sensor mat. A first subset of the item detection sensors are sensed at a first time, and a second subset of the item detection sensors are sensed at a second time. The item detection sensors of the first and second subsets are chosen such that they span the surface of the sensor mat, and so that the sensors of the chosen subsets include all of the sensors of the mat after multiple sensing steps have been completed.

1 . A system for detecting the presence of or information about objects comprising:
 a mat having a detection surface for the placement of objects;   sensor hardware consisting of a first set of parallel conductors disposed along a first axis of said detection surface and a second set of parallel conductors disposed along a second axis of said detection surface, said second axis being at an angle crossing said first axis; and   powering and detection hardware configured to power said first set of conductors and detect signals at nodes formed by the intersection with said second set of conductors, said powering and detection hardware being configured to power a first subset of said first set of conductors and to detect signals from a second subset of said second set of conductors;   wherein said first subset of said first number of conductors and said second subset of said second set of conductors are chosen such that each of the first subset and the second subset form an intersecting node pattern that spans said detection surface along both axes with a substantially lower density than that formed by intersections of all conductors of the first and second sets.   
     
     
         2 . A system for detecting the presence of or information about objects comprising:
 a mat having a detection surface for the placement of objects;   sensor hardware consisting of a grid of item detection sensors, said grid having first and second axes; and   detection hardware configured to detect signals from a first subset of said item detection sensors at a first time and to detect signals from a second subset of said item detection sensors at a second time;   wherein said first subset of said item detection sensors and said second subset of said item detection sensors are chosen such that each of the first subset and the second subset form a detection pattern that spans said detection surface along both axes with a substantially lower density than that formed by all of said item detection sensors.   
     
     
         3 . The system of  claim 2  wherein said grid of item detection sensors consists of a grid of intersecting conductors in a force sensitive resistor array. 
     
     
         4 . The system of  claim 2  wherein said grid of item detection sensors consists of a grid of capacitance sensing switches. 
     
     
         5 . The system of  claim 2  wherein said grid of item detection sensors consists of a grid of light-detecting sensors. 
     
     
         6 . A method of detecting the presence of or information about objects comprising:
 providing a mat having a detection surface for the placement of objects and a plurality of sensor nodes;   selecting and scanning a first subset of said sensor nodes;   selecting and scanning a second subset of said sensor nodes;   determining whether the steps of selecting and scanning said first and second subsets of sensor notes has resulted in all of said sensor nodes having been scanned; and   continuing to select and scan additional subsets of said sensor nodes until all of said sensor nodes have been scanned.