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Contactless proximity sensor with multilevel response

  • US 4,424,458 A
  • Filed: 10/07/1981
  • Issued: 01/03/1984
  • Est. Priority Date: 10/09/1980
  • Status: Expired due to Term
First Claim
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1. A contactless proximity sensor comprising:

  • a detector of incoming signals indicative of the presence of an object in a predetermined area;

    a threshold circuit connected to said detector and provided with a first, a second and a third output respectively energized in the presence of an incoming signal surpassing a low, an intermediate and a high level;

    a visual indicator;

    load-control means connected to said second output for performing a switching operation in response to an incoming signal exceeding at least said intermediate level; and

    pulse-generating means connected independently of said indicator to said first, second and third outputs for flashing said indicator at a relatively low rate in response to incoming signals lying in a lower range between said low and intermediate levels and flashing said indicator at a relatively high rate in response to incoming signals lying in an upper range between said intermediate and high levels, said rates lying within the range of visual perception.

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