Electric field sensing device

Abstract

A sensing system is disclosed that uses at least one conductive plate and associated electronic circuitry to provide an output that is indicative of an object's position in relation to the at least one conductive plate. The sensing system is provided with a high impedance drive signal that varies as a result of the location of an object relative to the at least one conductive plate. The electronic circuitry receives a high impedance drive signal value as an input and a processor uses the value to calculate a digital output indicative of the object's position. The high impedance drive signal value is monitored over time enabling the objects position, displacement, pressure, movement, impact and energy to be determined. This data is output to a display and may also be transmitted to a person located remotely from the object being monitored.

1 - 70 . (canceled) 
     
     
         71 . An apparatus comprising:
 an alternating current source;   a conductive member configured to produce an electric field in response to a signal associated with an output of the alternating current source; and   a processing circuit electrically coupled to the conductive member, the processing circuit configured to detect a change in an output of the conductive member associated with at least one of a position or a movement of a conductive body disposed within the electric field, the processing circuit having a processor configured to operate substantially synchronous with the alternating current source.   
     
     
         72 . The apparatus of  claim 71 , further comprising:
 a resistor electrically coupled to the alternating current source such that the signal associated with the output of the alternating current source is a high-impedance drive signal.   
     
     
         73 . The apparatus of  claim 71 , further comprising:
 a sensor configured to detect the output of the alternating current source and to generate a reference signal substantially synchronous with the output of the alternating current source.   
     
     
         74 . The apparatus of  claim 71 , wherein the output of the alternating current source is a reference signal, the apparatus further comprising:
 a resistor configured to receive the reference signal from the alternating current source and to supply a drive signal to the conductive member, the processing circuit including an amplifier in parallel with the resistor, the amplifier configured to output a signal associated with a difference between the drive signal and the reference signal.   
     
     
         75 . The apparatus of  claim 71 , wherein the processor is configured to phase lock with the output of the alternating current source. 
     
     
         76 . The apparatus of  claim 71 , wherein the output of the alternating current source is a reference signal, the processing circuit includes:
 a resistor configured to receive the reference signal from the alternating current source and to supply a drive signal to the conductive member; and   an analog to digital converter, the processor configured to cause the analog to digital converter to sample the drive signal in phase with the reference signal, such that a frequency variation of the drive signal induced by a frequency variation of the reference signal is substantially eliminated.   
     
     
         77 . The apparatus of  claim 71 , wherein the conductive member is a first conductive member, the conductive body is a second conductive member that is electrically grounded, the apparatus further comprising:
 a first compressible insulating member disposed between the first conductive member and the second conductive member;   a third conductive member that is electrically grounded, the first conductive member disposed between the third conductive member and the second conductive member; and   a second compressible insulating member disposed between the first conductive member and the third conductive member, at least one of the first compressible insulating member or the second compressible insulating member configured to deform when a force is applied to at least one of the second conductive member or the third conductive member, the deformation of the at least one of the first compressible insulating member or the second compressible insulating member allowing movement of the at least one of the second conductive member or the third conductive member relative to the first conductive member to alter the output of the conductive member.   
     
     
         78 . An apparatus comprising:
 a first conductive member configured to receive a drive signal and to produce an electric field in response to receiving the drive signal;   a second conductive member disposed within the electric field, a movement of the second conductive member within the electric field configured to alter the drive signal; and   a processing circuit configured to measure the alteration of the drive signal, the processing circuit having a processor configured to operate substantially synchronous with the drive signal.   
     
     
         79 . The apparatus of  claim 78 , wherein the processing circuit is configured to measure the alteration of the drive signal by comparing the drive signal to a reference signal. 
     
     
         80 . The apparatus of  claim 78 , further comprising an insulating member disposed between the first conductive member and the second conductive member. 
     
     
         81 . The apparatus of  claim 78 , wherein the second conductive member is electrically grounded, the apparatus further comprising:
 a compressible insulating member disposed between the first conductive member and the second conductive member, a deformation of the compressible insulating member associated with the movement of the second conductive member.   
     
     
         82 . The apparatus of  claim 78 , further comprising:
 an alternating current source configured to generate a reference signal; and   a resistor electrically coupling the alternating current source to the first conductive member, the resistor configured to receive the reference signal and to output the drive signal, the processing circuit being parallel to the resistor.   
     
     
         83 . The apparatus of  claim 78 , further comprising:
 an alternating current source configured to generate a reference signal; and   a resistor electrically coupling the alternating current source to the first conductive member, the resistor configured to receive the reference signal and to output the drive signal, the processing circuit configured to measure the alteration of the drive signal by comparing the reference signal to the drive signal.   
     
     
         84 . The apparatus of  claim 78 , wherein the apparatus is configured to measure at least one of a displacement, a position, or a pressure of a target, the movement of the second conductive member being associated with the at least one of the displacement, the position, or the pressure of the target. 
     
     
         85 . A method comprising:
 generating a drive signal configured to produce an electric field at a conductive member when the drive signal is received at the conductive member;   measuring, at a processor, a reference signal associated with the drive signal, the processor being phase locked to at least one of the drive signal or the reference signal when the reference signal is measured; and   detecting at least one of a position or a movement of a conductive body disposed within the electrical field based on a comparison of the drive signal to the reference signal.   
     
     
         86 . The method of  claim 85 , wherein:
 the reference signal is generated by an alternating current source, and   a resistor is configured to receive the reference signal and output the drive signal.   
     
     
         87 . The method of  claim 85 , wherein the drive signal is a high-impedance drive signal. 
     
     
         88 . The method of  claim 85 , wherein the at least one of the position or the movement of the conductive body is associated with breathing. 
     
     
         89 . The method of  claim 85 , wherein:
 a compressible insulator is disposed between the conductive member and the conductive body, the at least one of the position or the movement of the conductive body being associated with a deformation of the compressible insulator.   
     
     
         90 . The method of  claim 85 , wherein a processing circuit having the processor includes an analog to digital converter, the method further comprising:
 triggering the analog to digital converter in phase with the reference signal to substantially eliminate a frequency variation of the drive signal induced by a frequency variation of the reference signal.