Traffic light system using 555 timer

Re: Traffic light system using 555 timer

22 Feb 2017 #2

~~[quote=Peacock post_id=144 time=1487771826 user_id=77]~~ I want to build a traffic light system that uses only the 555 timer with astable and monostable configuration only (without decoder or counter). Please help me..... [/quote] I suggest that you connect the 555s (configured as monostables) in a ring.

For example, say you wanted just a red, amber and green lights on for say 1 minute, 15 sec and 1 minute respectively.

Mono A would drive the Red light and be set for 1 min
Mono B - amber
Mono C - Green.

When the outoput of Mono A goes low, it triggers Mono B, when Mono B goes low it triggers Mono C. The cycle re-starts when Mono C goes low.

You may need a pulse to start the sequence when the power is switched on, but I suspect it won't be necessary as the monos will quickly lock into the correct sequence.

A counter or shift register solution would be more elegant.
Recommended Tutorial: ~~[url=http://www.theengineeringprojects.com/2015/05/traffic-signal-control-using-555-timer-in-proteus-isis.html]~~Traffic Signal Control using 555 Timer[/url]