T junction traffic light project

Thread Starter

shaked194

Joined Mar 26, 2020
16
Hello, i need to plan a T junction traffic light system, using a 555 timer a-stable mode operating in 1 Hz as a clock.
i need help with designing a controller (counter and FF) which will provide a 6 sec output followed by 3 sec output
and then back again to 6 sec and so on.
I'm sorry but my English isn't perfect



6 sec 3 sec 6 sec 3 sec
מערכת רמזורים.PNG
 

dl324

Joined Mar 30, 2015
11,458
Welcome to AAC!
i need help with designing a controller (counter and FF) which will provide a 6 sec output followed by 3 sec output
and then back again to 6 sec and so on.
Post the work you've done so far.

What is the on time for each color?
 

Thread Starter

shaked194

Joined Mar 26, 2020
16
im in early-stage and having a serious problem with the conception.
i don't fully understand if i need one or two counters...
I've managed to produce a 5 sec up 1 sec down output for the upper counter
and 2 sec up 1 sec down output for the lower counter

I want to use some kind of flip flops to control the output signal.

thank you very much



v,jkv.PNG
 

dl324

Joined Mar 30, 2015
11,458
What is the on time for each color? You mentioned 6-3-6-3. Does that mean yellow is on for 3 seconds?
 

Thread Starter

shaked194

Joined Mar 26, 2020
16
well i think i mistakenly thought about it analogically because of the need for specific timing.
i need some kind of state machine to derive it, i just don't know where to begin
 

Thread Starter

shaked194

Joined Mar 26, 2020
16
its a mini-project at the university.
its actually more complicated than what I've said here,
but this is my main struggle.
i need to understand the "controller block" which keeps the system sync, inputs and outputs
 

dl324

Joined Mar 30, 2015
11,458
i need to understand the "controller block" which keeps the system sync, inputs and outputs
What are your ideas for this?

What are you showing us in post #3? You have 6 lights to control and you show decoding for 2. How did you derive that logic?
 

Thread Starter

shaked194

Joined Mar 26, 2020
16
I've said before, it was just a hunch.
so what you are saying is that I need actually 6 lights to control, 3 for each traffic light.
any suggestions about where to begin? which counter to use? what about the state machine?

thank you, shaked
 

dl324

Joined Mar 30, 2015
11,458
I think the picture depicts 3 states of two sets of lights... There should be two of one and one of the other..
What do you mean? There are 6 lights that need to be controlled. Because of the timing, multiple lights can't be controlled by the same logic.
 

Ian Rogers

Joined Dec 12, 2012
804
What do you mean? There are 6 lights that need to be controlled. Because of the timing, multiple lights can't be controlled by the same logic.
Oh!! You are talking about the red green yellow... Sorry that was a given... I was talking about the traffic light as a whole... A Tee junction needs three

Over here we do have multiple.. Amber Red.. "Get ready to go"
 

ci139

Joined Jul 11, 2016
1,696
there are variety of ways to set it up but basically these light are "phase shifted"
so you can use counter and adder --or-- counter and 2 decoders --or-- set up the same "state machine" for each direction and initiate them to proper phase shift (perhaps also making sure the phase shift stays what it suppose to be) .... etc. more versions
your states ::
-TIME 6 3 6 3
MAIN G Y R R
...SIDE R R G Y ( " 180° " )
 

djsfantasi

Joined Apr 11, 2010
6,786
What do you mean? There are 6 lights that need to be controlled. Because of the timing, multiple lights can't be controlled by the same logic.
There are two, identical sets of three lights for Main. One in each direction. There is no additional logic for this. In actuality, there are nine lights.
 

Thread Starter

shaked194

Joined Mar 26, 2020
16
There are two, identical sets of three lights for Main. One in each direction. There is no additional logic for this. In actuality, there are nine lights.

well the main road lights can be considered as one traffic light.
so there are two sets - main and side. in total 6 lights
 
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