In Reply to: Re: TRAFFIC LIGHTS frequency posted by B on June 27, 2000 at 20:30:39:
: : : : i notice my radar detector now goes off at every intersection. the signal changes with the light. i know this is to allow the police/fire to change the light. it would be pretty cool to be able to do that, not that i would. wondering how.
: : : Today when an aid or a fire vehicle was responding somewhere, I heard it radio dispatch, give the location of the light, and ask to turn it red.
: : I dont know about any frequencies they emit but i do know that they have photo cell sensors that look like a small eyesomewhere on the crossbeam where the lights hang.if you have the right angle you can flash your brights on and off a few times and change the light green immediately for yourself. another way is to have a super bright flashlight or spotlight and aim it straight at the photo cell and flash it on and off quickly
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: Most, if not all (except Seattle), FD's around here have 3m opticoms. They flash at an incredibly high rate, so you may think that you're changing the light when you flash your brights, but you're not. You can't flash them fast enough to trigger the sensor. I'm guessing they flash at something like 500 per minute.
its called a strobe light!!