need an electronic traffic lightx ckt!!!!

Thread Starter


Joined Mar 25, 2008
pls, i have a projet on traffic lighting to be studied and realised. can some1 out there help me with an electronic circuit to satisfy traffic lighting? i'll b most gateful!!!!


Joined Jan 28, 2005
Can you provide some additional information? Are you looking to make this a microcontroller based design for example? Will there be any sensors involved?



Joined Mar 24, 2008
This could be simple, or it could be hard. I would assume you need 4 way stop, which is slightly more complex. Nowdays the real deal uses microprocessors, but discrete logic could do it very simply. Where it get more complex is if there are sensors (as real intersections have in many cases) and extras like turn arrows.

Timing is also important, how long will the green light stay on, and the yellow light? The red light could be safely assumed to be the duration of the other two added together.


Joined Apr 2, 2008
In the real world a traffic light controller must be equipped with an independent Conflict Monitor Unit. If a malfunction in the controller ever allows traffic to proceed from opposing directions, the CMU will set all directions to flashing red. You can find more information about signal design at traffic signals 101.
There is a very simple traffic light controller circuit, intended for model railroad use, at