Electronics > Beginners
Traffic light circuit with 556 timer?
phennessey:
Unpopular opinion: That’s a bad idea. Giving people an exact preview of when the light will turn green is only allowing the possibly for abuse and increases the chance for a collision.
james_s:
--- Quote from: phennessey on December 26, 2019, 12:43:32 pm ---Unpopular opinion: That’s a bad idea. Giving people an exact preview of when the light will turn green is only allowing the possibly for abuse and increases the chance for a collision.
--- End quote ---
How so? You can already get this exact preview if you look at the lights on the cross street. Only an idiot steps on the gas before visually confirming the intersection clear, and the point of the amber light before red is to ensure the intersection is clear before the other direction gets a green. The fact that there are always a few idiots incapable of following the rules is a constant either way.
phennessey:
Idiots exist, ergo, why give them more ways to be idiots? Sometimes people run red lights. Why give people an incentive to gun it just when the light turns green? It’s certainly not safer to give people advance notice of a green light.
SmokeyTheElectrician:
--- Quote from: james_s on December 26, 2019, 04:32:34 am ---There's lots of information out there about traffic light controllers, at least the stuff used in the US. Eagle, Econolite and Crouse-Hinds were some of the big makers here. Early systems used motor driven timing wheels and solenoids, then in the early 80s microprocessor based controllers started taking over.
https://northstarhighways.wordpress.com/2016/09/10/how-traffic-signal-controllers-work-part-1-an-overview-of-controllers/
--- End quote ---
--- Quote from: schmitt trigger on December 25, 2019, 10:13:57 pm ---Back in the early 70s, I worked for a summer for the city’s traffic light department, in maintenance.
There were a couple of systems, that I remember:
-Relay ladder logic as you described.
-A camshaft driven by a 1RPM geared synchronous motor.
--- End quote ---
Thanks for the insights and link to the interesting reading / vidoes.
james_s:
--- Quote from: phennessey on December 26, 2019, 06:29:30 pm ---Idiots exist, ergo, why give them more ways to be idiots? Sometimes people run red lights. Why give people an incentive to gun it just when the light turns green? It’s certainly not safer to give people advance notice of a green light.
--- End quote ---
Because it gives people a heads up so they are prepared to go, it's nice to have a chance to put the car in gear before the guy behind starts having a cow. I'm just not seeing this incentive to gun it created by a warning, can you find me some data showing it happens in any of the places where this is commonplace? Someone who is going to gun it at a green light is going to do so whether they have a yellow light or not.
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