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Traffic Light Control For The Masses
uniformed1 writes "Eliminating red lights along the routes of their vehicles can give
emergency response teams the few extra critical minutes that can save
lives and property. A front page article
in today's Detroit News details
the emerging problem with a device that is now being made available to
the public -- a traffic light changer. Originally intended only
for emergency vehicles, the $300 MIRT (mobile infrared transmitter)
emits an infrared beam that signals traffic signals to turn green and
gives the vehicle the right-of-way. It is only a matter of time
before self-centered drivers start using the devices widely to skirt
traffic congestion, which is creating fears that chaos will
ensue." Maybe if everyone had these, it would lead to smarter intersections.
www.themirt.com has a lot of info on these devices. Even a dealer list of where to get one. Man, I'm tempted...
-mikey
your average CCD will detect IR. Don't believe me? Pull out your camcorder and aim a remote at the camcorder. It looks like white light. I know where I live, we have CCD DOT cams at almost every intersection. It would be easy to pick out the car emitting the bright flashes.
The traffic light control system itself is called Opticom . It is patented and manufactured by 3M.
It operates using very short pulses of light (< 10uS) occuring at a precise frequency (usually crystal controlled). The normal pulse rate is about 10Hz. An optional rate of around 12.5Hz can be used to give priority to other vehicles (ex. ambulance vs firetruck).
The system is configurable and normally set to give a green light to the emergency vehicle (helping to clear traffic) but it can also be set to go red in all directions.