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Anti-entrapment system

  • US 9,389,062 B2
  • Filed: 03/15/2013
  • Issued: 07/12/2016
  • Est. Priority Date: 07/09/2001
  • Status: Active Grant
First Claim
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1. A sensor device comprising:

  • a capacitance sensor, wherein a capacitance of the capacitance sensor changes in response to a conductive object coming into proximity of the capacitance sensor; and

    a plurality of charge storing capacitors;

    a controller including a micro-controller configured to;

    closing a first switch to develop an electrical charge in the sensor by placing a known voltage from a voltage source across conductors of the capacitance sensor;

    opening the first switch to isolate the capacitance sensor from the voltage source;

    closing a second switch to instigate a charge transfer between the capacitance sensor and at least one charge storing capacitor of the charge storing capacitors, wherein the transferred charge from the capacitance sensor is indicative of the capacitance of the capacitance sensor;

    opening the second switch to isolate the at least one charge storing capacitor from the sensor;

    determine the capacitance of the capacitance sensor based on the transferred charge;

    wherein the controller is operable to select a number of the plurality of charge storing capacitors for the charge transfer with the capacitance sensor to reach a target capacitance value of the plurality of charge storing capacitors; and

    wherein the selected number of the plurality of charge storing capacitors corresponds to a sensitivity of the device.

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