TRaffic lights project

wowzone2009 · Dec 6, 2011

Hello its my first project , would your please advise me or help me . i would thank you !
Traffic light system
Design a digital logic circuit for a traffic light system. You are free to choose the
traffic light arrangements and operations. An example of traffic light system is shown
at a two dual-carriage roads meet at a T junction, as shown in Figure 1. Three traffic
lights (E, W and S) placed at this junction are to be set up and controlled by a digital
logic system.

wowzone2009 · Dec 6, 2011

so if its school one please help me professorial person

4pyros · Dec 6, 2011

start here;
https://www.doc.ic.ac.uk/~dfg/hardware/HardwareLecture10.pdf
Andy

wowzone2009 · Dec 6, 2011

Lol i can not use that ! i need counters , 555 timer , and its 3 traffic lights A B C in T junction , i should just use logic design .

4pyros · Dec 6, 2011

wowzone2009 said:
Lol i can not use that ! i need counters , 555 timer , and its 3 traffic lights A B C in T junction , i should just use logic design .

I think the link I provided explanes how to meet your requierments for your assignment to a "T" no pon intended.
Did you read it?

You are free to choose the
traffic light arrangements and operations.

So you could use a "T" or an "X" right?
In the lesson I linked to it clearly shows you need a clock. You could use a 555 timer right?

wowzone2009 · Dec 6, 2011

yes .
its my arrangement for A B C
if A GREEN , B AND C RED
IF B GREEN , A AND C RED
IF C GREEN . B AND A RED
SO
A B C Sequence
G R R 0
G R R 1
G R R 2
Y R R 3
R G R 4
R G R 5
R Y R 6
R R G 7
R R G 8
R R Y 9

wowzone2009 · Dec 6, 2011

also i use one monostable 555 timer T = 1.1 × R1 × C1 and one decode IC 4017 . so as you see i have got everything , so might you help me . i need to use 6 BJT , which all collector is +9 v . and emitter is my LEDS , can you help me with simulation ?

audioguru · Dec 8, 2011

[mod edit: off topic]

ljcox · Dec 8, 2011

wowzone2009 said:
also i use one monostable 555 timer T = 1.1 × R1 × C1 and one decode IC 4017 . so as you see i have got everything , so might you help me . i need to use 6 BJT , which all collector is +9 v . and emitter is my LEDS , can you help me with simulation ?

Perhaps I'm missing something, but as far as I can see, you have 9 LEDs therefore you need 9 BJT to drive them.

If so, then you can do the logic either with OR gates or with diode gates.

BTW the 4017 counts from 0 to 9, not 1 to 10.

0 is the first digit of all numbering systems.

The 4017 may not necessarily be the best counter for this job. A binary counter may be better. See my post#22 in this thread. https://www.electro-tech-online.com/threads/led-5-blinks-and-then-a-continuous-light.123628/

wowzone2009 · Dec 8, 2011

ljcox said:
Perhaps I'm missing something, but as far as I can see, you have 9 LEDs therefore you need 9 BJT to drive them.

If so, then you can do the logic either with OR gates or with diode gates.

BTW the 4017 counts from 0 to 9, not 1 to 10.

0 is the first digit of all numbering systems.

The 4017 may not necessarily be the best counter for this job. A binary counter may be better. See my post#22 in this thread. https://www.electro-tech-online.com/threads/led-5-blinks-and-then-a-continuous-light.123628/

Thank you for your information , it was very good and helpful . can you give me one simulation for that ?

ljcox · Dec 8, 2011

wowzone2009 said:
Thank you for your information , it was very good and helpful . can you give me one simulation for that ?

You're welcome.

I do my designs on paper, not by simulation.

I have drawn the A case for you. See if you can do the B & C cases.

When you have done it, please post your circuit so we can advise you.

Note that I saved some components by using a NOR gate to drive the Red LED.

The logic is if the Green & Yellow LEDs are off, then the Red one needs to be ON.

Edit:
I have replaced the circuit with a marginally better one.

The changes are in red.

wowzone2009 · Dec 9, 2011

man i dont understand that , why u write
0 3
1 2
2 4
...
in the counter , what is 3 , 2 , 4?

ljcox · Dec 10, 2011

wowzone2009 said:
man i dont understand that , why u write
0 3
1 2
2 4
...
in the counter , what is 3 , 2 , 4?

Did you look at the data sheet of the 4017?

0 is output 0 which is connected to pin 3 of the IC.

1 is output 1 which is connected to pin 2, etc.

See page 2 of the attachment.

wowzone2009 · Dec 10, 2011

ok i made this simulatin , but in run it has some problem
1 ) green and red trun one together
2) C last traffic light Green and yellow blinking and red one wont turn one
3) when theone trafic light is green others are not red !
would you help me

wowzone2009 · Dec 10, 2011

this is for logic
G R R 0
G R R 1
G R R 2
Y R R 3
R G R 4
R G R 5
R Y R 6
R R G 7
R R G 8
R R Y 9

4pyros · Dec 10, 2011

You need to lable all the LEDs so we can see whats going on.

colin55 · Dec 10, 2011

Here is a circuit:
4 WAY TRAFFIC LIGHTS
This circuit produces traffic lights for a "4-way" intersection. The seemingly complex wiring to illuminate the lights is shown to be very simple.
**broken link removed**

ljcox · Dec 10, 2011

colin55,
That is interesting but confusing.

1. It does not agree with his table at posts #9 or #18. There are too many greens in your diagram

2. The 4017 outputs are labled Q0 ~ Q9 but your output numbers are labled 1 ~ 10.

3. He has 3 columns in his table, but your output diagram has only 2 rows.

Please elaborate.

4pyros · Dec 10, 2011

ljcox said:
colin55,
That is interesting but confusing.

1. It does not agree with his table at posts #9 or #18. There are too many greens in your diagram

2. The 4017 outputs are labled Q0 ~ Q9 but your output numbers are labled 1 ~ 10.

3. He has 3 columns in his table, but your output diagram has only 2 rows.

Please elaborate.

The circuit Colin posted is from the web and is for a four way stop light. The OP is trying to make a 3 way stop light.

wowzone2009 · Dec 10, 2011

would you all stop copy from other website . my question is very clear . ( i have seen all web sites )
i need T junction traffic light . ( A B C)
when one is green or yellow others be Red .
10 sequences .
G R R 0
G R R 1
G R R 2
Y R R 3
R G R 4
R G R 5
R Y R 6
R R G 7
R R G 8
R R Y 9
SO BETTER YOU KNOW ,that i know what i want and what is going one ! just please if u know how to design the 3 Led with Counter that give me those result , give me your opinian .
Thank You

TRaffic lights project

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