Natwerk Designs

how to design a traffic light?

A T-junction with three traffic lights (E,W & S) they are to be setup and controlled by a digital logic system.

Public Comments

1. The key components are - a '555' timer IC - a CMOS 4017 decade counter put together like so http://www.kpsec.freeuk.com/projects/trafficlight.htm For a T-junction, you have to connect more LEDs, when branch is red then through-road is green, and so on. This will require driver transistors for the LEDs, like so http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm#traffic.gif (scroll down to "LED Traffic Lights" schematic) You may have to modify it a bit, for example, if in your country there is no yellow light between red and green.
2. You can use a micro like 8051,it is very simple to program it,you can have different time when the red light is on and the green light is on.in your program you set one pin that connected to the led then go to subprogram that is delay.then reset that pin and set another pin...