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Motion detection system and associated methods having at least one LED of second set of LEDs to vary its voltage

  • US 8,680,457 B2
  • Filed: 01/11/2013
  • Issued: 03/25/2014
  • Est. Priority Date: 05/07/2012
  • Status: Active Grant
First Claim
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1. A lighting system for detecting movement comprising:

  • a first set of light emitting diodes (LEDs);

    a second set of LEDs;

    a voltage sensor coupled to an LED of the second set of LEDs defining a coupled LED; and

    a controller functionally coupled to each of the first and second sets of LEDs;

    wherein the controller is configured to continuously operate the first set of LEDs to emit light within a field of view of the first and second sets of LEDs;

    wherein the controller is configured to operate the second set of LEDs in alternating active and passive states;

    wherein the controller is configured to operate the second set of LEDs to emit light in the active statewherein the controller is configured to operate the second set of LEDs to not emit light in the passive state and maintain a baseline voltage;

    wherein the voltage sensor is configured to monitor the voltage of the coupled LED during the passive state;

    wherein the coupled LED is configured to vary the voltage there across upon incidence of light reflected by a target; and

    wherein a change of voltage from the baseline voltage in the coupled LED during the passive state indicates the detection of a target within the field of view of the first and second sets of LEDs.

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