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RE: blakesley hall

 by Voltman , Sun Jun 27, 2010 11:31 pm

A photo sensor was a simple infra red device. A transmitter unit (Tx) projects a beam of infra red light across a space toward a receiver unit (Rx) and if the beam isn't received for any reason the receiver would actuate a relay, This may have switched a counter, or perhaps a sounder to alert the curator to the fact that someone had entered or departed through the front gate. The curators desk was just inside the front door, to the left a you go in.

Photo sensors now usually have a mirror to reflect the beam back and the Tx and Rx are in the same unit.
Some very advanced photo sensors really are cameras that can compare a preset image with a real time image and generate an alarm if the images don't match.
Volty


"Nothing is more dangerous than an idea when it is the only one you have." Emile-Auguste Chartier
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Voltman
Posts: 18.439
Date registered 02.24.2010

Thread overview

Subject Author Date
blakesley hall astoness 06.27.2010
RE: blakesley hall astoness 06.27.2010
RE: blakesley hall astoness 06.27.2010
RE: blakesley hall Voltman 06.27.2010
RE: blakesley hall astoness 06.27.2010
RE: blakesley hall Voltman 06.27.2010
RE: blakesley hall Sheldonboy 06.28.2010
RE: blakesley hall astoness 06.28.2010
RE: blakesley hall 06.28.2010
RE: Blakesley Hall Sheldonboy 06.29.2010
Blakesley Hall Voltman 05.03.2010
RE: Blakesley Hall Voltman 05.03.2010
RE: Blakesley Hall signman 05.03.2010
RE: Blakesley Hall 05.03.2010
RE: Blakesley Hall phil 05.03.2010
RE: Blakesley Hall Sheldonboy 05.03.2010
RE: Blakesley Hall Voltman 05.03.2010
RE: Blakesley Hall signman 05.03.2010
RE: Blakesley Hall Sheldonboy 05.03.2010
RE: Blakesley Hall signman 05.03.2010
RE: Blakesley Hall Voltman 05.03.2010
RE: Blakesley Hall signman 05.03.2010
RE: Blakesley Hall Voltman 05.05.2010
 

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