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Traffic signal system for blind people

  • US 4,253,083 A
  • Filed: 03/15/1978
  • Issued: 02/24/1981
  • Est. Priority Date: 12/19/1977
  • Status: Expired due to Term
First Claim
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1. A traffic signal system for blind people installed in combination with a common traffic signal device for pedestrians, comprisinga signal generator circuit electrically coupled to a blue light of the pedestrian traffic signal device for generating an audible sound signal synchronous with lighting of said blue light,a noise detector circuit for detecting the surrounding noise,a volume control circuit connected to said signal generator circuit and said noise detector circuit for controlling the output of said signal generator circuit in accordance with the output of said noise detector circuit, anda speaker electrically connected to said volume control circuit, whereby an audible sound having a volume corresponding to the level of the surrounding noise is produced from the speaker.

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