Article View: sci.electronics
Article #21584Re: Car Detectors for Traffic Lights
From: Larry Lippman
Date: Fri, 02 Jun 1989 01:33
Date: Fri, 02 Jun 1989 01:33
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In article <1741@ucsd.EDU>, brian@ucsd.EDU (Brian Kantor) writes:
> As I recall, there were two frequencies sensed by the traffic light
> controller - one would simply extend the green and was for use by
> transit buses and such to save on gas and brakes, and the other
> caused immediate green in one direction and red elseways. I don't
> remember the exact frequencies but they were slower than 20Hz, as
> I recall.
>
> I'm told that's now illegal: "tampering" with a traffic signal.
> There's entirely too much law these days.
Gee, it's too bad they don't have those kind of traffic lights in
the area of NY State where I live; I could have some fun. :-)
I wonder if the traffic light optical sensors are sensitive to
IR, and would trip from some pulsed IR energy from a high-power diode
array? This would certainly result in a rather unobtrusive, ahem,
"automotive accessory". I tend to feel that any optical sensor of
this nature would respond to some really _decent_ IR energy, as
emitted from an injection laser diode. However, a laser diode does
present some safety concerns, in addition to a directivity problem due
to lack of beam dispersion.
<> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: sci.electronics Subject: Re: Car Detectors for Traffic Lights Summary: Having "fun" with IR... Message-ID: <3205@kitty.UUCP> Date: 2 Jun 89 01:33:45 GMT References: <18811@cup.portal.com> <3185@kitty.uucp> <456@antares.uucp> <1741@ucsd.EDU> Organization: Recognition Research Corp., Clarence, NY Lines: 27