Hello friends,
i am in my final year and the project i am working on is of the topic: Design and construction of traffic control system using 555 timer in an astable mode.
pls i need your assistance on how to go about it
thanks
Segun

 

Since this is homework, we can't do it for you, but we can help you along the way.

If the 555 is to be used in an astable mode, then it would make a decent clock signal.

Figure out what the smallest division of time is for a traffic signal. Time a real one.

Then design a circuit using a 555 that will produce a square wave clock signal output that is approximately equal to that smallest time division.

Here are some 555 tutorial pages for you:
http://williamson-labs.com/555-tutorial.htm
http://www.uoguelph.ca/~antoon/gadgets/555/555.html
http://www.g8ajn.tv/technical.htm
http://www.electronics-tutorials.com/devices/555.htm

After you get the timer portion working, you can look at using digital logic IC's to keep track of how many clock signals your timer has put out, and sequence the green-yellow-red light combinations.

 

I think you would be expected to use a 555 for more than just a clock signal in your project.

Don't forget that the 555 contains, two comparators, and an output stage with quite a hefty current capability. Plus it has the ability to operate from a wide range of voltages.

You can use these properties to construct gating circuits to control and drive your signals.

Good luck

 

http://www.ectinschools.org/page.php?ps=2&p=3
Here there is one.