Traffic light

[jude3085]

Hey,
I need to construct a traffic light and need some help. Anyone know of any good resources that will be of any help? I would prefer a step by step manual if its possible. Any information will be appreciated.
Thanks.

p.s
We will be using leds for the lights. The main project has to do with sequential logic, using flip flops or counters.

 

[john1]

Hi jude,

It has long been a challenge to me,
since student days,
to construct a simple three LED traffic light set,
red LED, amber LED, green LED,
using the minimum number of components possible.

I have made many such units,
some free running with intervals up to about seven
seconds, and some not free running which change state
from a press-button.

It is this latter type using a press button that i have
managed to reduce to less than twelve discrete
components.

It may be possible to do it with even fewer components,
but i have not managed it yet.

Best of luck with your studies, i would be most
interested to see how you get on.

Regards, John

 

[Russlk]

Are you given any rules about how this trafic light works? Or does it just sequence from green to yellow to red to green?

 

[john1]

Hi Russlk,

The usual pattern of a single traffic-light pole
is often used as a practise piece for students of
small breadboard type chip and gate assemblies.

Making it approximate the normal pattern looks
like a fairly simple job.

A long interval, and a short interval.
Three lamps or LEDs gated up accordingly.
Easy to see straight off if its right or not.

Making it come out right does involve a good bit
of thinking, and figuring things out.

I doubt if he is required to provide for a full
set of traffic lights such as a crossroads,
my guess is that the pattern from a single traffic
light pole is all that is wanted.

Regards John

 

[grrr_arrghh]

You could use a decade counter (like a 4017), with a push switch connected somewhere (!) to start the cycle. To me that's the easiest way.

Tim

 

[oxygen454]

hey man, I just built a traffic light and it works. I got it from the city so yeah its a real working light. On here somewhere in this forum I have a detailed way to wire it up. Let me know if you need more help!

 

[akintunde]

i need a design for a traffic light that has a sound output with each light.