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Apparatus and method for monitoring the output of a warning or indicator light

  • US 7,123,165 B2
  • Filed: 07/26/2004
  • Issued: 10/17/2006
  • Est. Priority Date: 07/26/2004
  • Status: Active Grant
First Claim
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1. An operational status detection system for a railroad warning device having a warning light, comprising:

  • a photo detector configured to generate a signal corresponding to a light output of the warning light of the railroad warning device, said photo detector comprising a lens, an optical filter and a photodiode, wherein said optical filter is disposed between said photodiode and said lens and said optical filter is configured to provide the light output of the warning light received by said lens to be presented as a substantially uniform spatial response to said photodiode wherein areas of high intensity of the warning light that are received by the lens are attenuated, said areas of high intensity providing higher light outputs than other areas of the warning light; and

    a microcontroller receptive to said signal, wherein said microcontroller compares said signal to at least one threshold value, said at least one threshold value corresponding to an acceptable light output of the warning light.

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