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Real time bicolor led traffic light system

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tonderayi

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Hi
i am bouilding a real time adaptive traffic light system that uses bi-color led for lighting. I
need help in designing the bicolor led driver circuit and power supply FOR MY PROJECT. Please assist
 
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I wouldn't recommend it because if someone is red/green colour blind (quite common condition) they won't be able to tell whether it's on red or green.

Real traffic lights use separate lights because the position of the light indicates whether it's red or green and they don't use pure green but bluish-green so people with red/green colour blindness can still tell the difference.

I heard that when the Chinese Communist party first rose to power they reversed the meaning of red and green traffic lights so that red (symbolising socialism) meant go and green meant stop, soon chaos ensued so they changed it back. :D
 
I heard that when the Chinese Communist party first rose to power they reversed the meaning of red and green traffic lights so that red (symbolising socialism) meant go and green meant stop, soon chaos ensued so they changed it back. :D

A lot of the problem there was they didn't change the meanings of red and green across the whole country! So in some places it meant the opposite.
 
Hi
i am bouilding a real time adaptive traffic light system that uses bi-color led for lighting. I
need help in designing the bicolor led driver circuit and power supply FOR MY PROJECT. Please assist

Please tell us if you're using 2-pin or 3-pin Red/Green LEDs. And if 3-pin devices, please tell us if they are common cathode or command anode.
 
Myth: Doesn't work for colour blind

I wouldn't recommend it because if someone is red/green colour blind (quite common condition) they won't be able to tell whether it's on red or green.

Real traffic lights use separate lights because the position of the light indicates whether it's red or green and they don't use pure green but bluish-green so people with red/green colour blindness can still tell the difference.

This appears to be a misconception. Red/green colour blind is a generic term for four different types. There is red-blindness (protanopia) and green-blindness (deuteranopia), but more common is not blindness to a colour but weakness. A Deurtanomolous person can tell the difference especially as LED traffic lights have more even colour output and display higher contrast colours than older filtered incandescent traffic lights. Before LED traffic lights came along, each traffic signal aspect needed a separate colour fliter and the easiest way to do this was to have three bulbs, each with a separate filter, and I believe the bluish tint of green has something to do with the yellowish tint of incandescent light.
 
OK, This might sound silly but if it is a cluster of LED lights why not use shapes like an arrow for go and a cross for stop.......?
 
The trouble with the controversial Uni-signal

Becasue shapes aren't as visible from a distance as colour. A size 20 shape would only be visible from as far as 20 yards to someone with 20/20 vision. Thus a daltonists (red-blind or green-blind) would still need greater visual acuity to tell from more than a given distance than a colour normal person. Note that monochromats also would rely on shape to tell the colour, and their visual acuity is usually only marginal at best.
 
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