Resistance measurement array

Abstract

A system and method for measuring resistance over an array. The array includes at least three electrodes. Nodes at each intersection between input electrodes and output electrodes have variable resistance. A driving voltage is applied to a selected input electrode and an output current is received at a selected output electrode. A selected node is at the intersection of the two selected electrodes and includes an electrical component with a resistive property. Remaining electrodes are connected with a ground for isolating the selected node from the effects of changes in impedance of the remaining nodes. The driving voltage is converted to an output current by resistance at the selected node. The output current is converted to an output voltage with a current-to-voltage converter circuit for measuring the resistance of the electrical component. The nodes may be measured as the selected node in sequential or non-sequential patterns.

We claim: 
     
         1 . A system for measuring resistance, comprising:
 a plurality of electrodes arranged in an array, the plurality of electrodes comprising a plurality of input electrodes and a plurality of output electrodes, the array comprising a plurality of nodes, each node being defined at an intersection between an input electrode and an output electrode;   a switching system in operative communication with the plurality of electrodes for selecting a selected node, the selected node defined at an intersection between a selected input electrode and a selected output electrode, the selected node comprising an electrical component having a resistive property;   an input ground in communication with the array for grounding remaining input electrodes other than the selected input electrode, wherein the input ground is a first stable fixed voltage;   an output ground in communication with the array for grounding remaining output electrodes other than the selected output electrode, wherein the output ground is a second stable fixed voltage;   a driving voltage source in electrical communication with the selected input electrode for providing a driving voltage to the selected node; and   a current-to-voltage converter circuit in electrical communication with the selected output electrode for receiving an output current from the selected node and converting the output current to an output voltage.   
     
     
         2 . The system of  claim 1 , wherein the first stable fixed voltage and the second stable fixed voltage comprise a single shared stable fixed voltage. 
     
     
         3 . The system of  claim 1 , wherein the resistive property is variable in response to temperature. 
     
     
         4 . The system of  claim 1 , wherein the resistive property is variable in response to strain. 
     
     
         5 . The system of  claim 1 , wherein the resistive property is variable in response to pressure. 
     
     
         6 . The system of  claim 5 , further comprising an insole, wherein the array is disposed in the insole. 
     
     
         7 . The system of  claim 6 , wherein the system is configured to measure a body weight of a user wearing the insole based on the output voltage. 
     
     
         8 . The system of  claim 1 , wherein the switching system comprises:
 an input multiplexor for selecting the selected input electrode;   an output multiplexor for selecting the selected output electrode;   a plurality of input switches in electrical communication with the input multiplexor and the plurality of input electrodes, for establishing electrical communication between the selected input electrode and the driving voltage source, and between the remaining input electrodes and the first stable fixed voltage; and   a plurality of output switches in electrical communication with the output multiplexor and the plurality of output electrodes, for establishing electrical communication between the selected output electrode and the current-to-voltage converter circuit, and between the remaining output electrodes and the second stable fixed voltage.   
     
     
         9 . The system of  claim 8 , wherein the plurality of input switches and the plurality of output switches comprise single-pole double-throw switches. 
     
     
         10 . The system of  claim 1 , further comprising an analog-to-digital converter in electrical communication with the current-to-voltage converter circuit for receiving the output voltage and converting the output voltage to a digital signal; and
 a processor in electrical communication with the analog-to-digital converter for receiving the digital signal and processing the digital signal.   
     
     
         11 . The system of  claim 1 , wherein the driving voltage source comprises a DC voltage source. 
     
     
         12 . A method of measuring resistance, comprising:
 providing a plurality of electrodes arranged in an array, the plurality of electrodes comprising a plurality of input electrodes and a plurality of output electrodes;   providing a plurality of nodes in the array, each node defined at an intersection of an input electrode and an output electrode;   selecting a selected node at an intersection of a selected input electrode and a selected output electrode, the selected node comprising an electrical component having a resistive property;   grounding remaining input electrodes other than the selected input electrode by establishing electrical communication between the remaining input electrodes and a first stable fixed voltage;   grounding remaining output electrodes other than the selected output electrode by establishing electrical communication between the remaining output electrodes and a second stable fixed voltage;   applying a driving voltage to the selected input electrode;   converting the driving voltage to an output current through a resistance of the electrical component;   receiving the output current at the selected output electrode; and   converting the output current to an output voltage for measuring the resistance of the electrical component.   
     
     
         13 . The method of  claim 12 , wherein the first stable fixed voltage and the second stable fixed voltage comprise a single shared stable fixed voltage. 
     
     
         14 . The method of  claim 12 , wherein the resistance of the electrical component is variable and dependent on a temperature of an environment around the electrical component, and the method further comprises determining a value of the temperature at the selected node with reference to the resistance of the electrical component. 
     
     
         15 . The method of  claim 12 , wherein the resistance of the electrical component is variable and dependent on a strain of an environment around the electrical component, and the method further comprises determining a value of the strain at the selected node with reference to the resistance of the electrical component. 
     
     
         16 . The method of  claim 12 , wherein the resistance of the electrical component is variable and dependent on a pressure of an environment around the electrical component, and the method further comprises determining a value of the pressure at the selected node with reference to the resistance of the electrical component. 
     
     
         17 . The method of  claim 16 , wherein the array is disposed in an insole, and the method further comprises measuring a body weight of a user wearing the insole based on the output voltage. 
     
     
         18 . The method of  claim 12 , further comprising selecting the selected input electrode using an input multiplexor and selecting the selected output electrode using an output multiplexor. 
     
     
         19 . The method of  claim 12 , wherein selecting the selected node comprises establishing electrical communication between the selected input electrode and the driving voltage source and establishing electrical communication between the selected output electrode and the current-to-voltage converter circuit. 
     
     
         20 . The method of  claim 12 , further comprising receiving the output voltage and converting the output voltage to a digital signal; and
 receiving the digital signal and processing the digital signal.