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TRaffic lights project

Discussion in 'Homework Help' started by wowzone2009, Dec 6, 2011.

  1. wowzone2009

    wowzone2009 New Member

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    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.
     

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    Last edited by a moderator: Dec 6, 2011
  2. wowzone2009

    wowzone2009 New Member

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    so if its school one please help me professorial person
     
  3. 4pyros

    4pyros Well-Known Member Most Helpful Member

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  4. dave

    Dave New Member

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  5. wowzone2009

    wowzone2009 New Member

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    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 .
     
  6. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    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?
    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?
     
  7. wowzone2009

    wowzone2009 New Member

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    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
     
    Last edited: Dec 10, 2011
  8. wowzone2009

    wowzone2009 New Member

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    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 ?
     
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    ONLINE
    [mod edit: off topic]
     
    Last edited by a moderator: Dec 10, 2011
  10. ljcox

    ljcox Well-Known Member

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    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. http://www.electro-tech-online.com/threads/led-5-blinks-and-then-a-continuous-light.123628/
     
    Last edited: Dec 8, 2011
  11. wowzone2009

    wowzone2009 New Member

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

    ljcox Well-Known Member

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    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.
     

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    Last edited: Dec 9, 2011
  13. wowzone2009

    wowzone2009 New Member

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

    ljcox Well-Known Member

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    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.
     

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  15. wowzone2009

    wowzone2009 New Member

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    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
     

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  16. wowzone2009

    wowzone2009 New Member

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    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
     
  17. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    You need to lable all the LEDs so we can see whats going on.
     
  18. colin55

    colin55 Well-Known Member

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    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.
    [​IMG]
     
  19. ljcox

    ljcox Well-Known Member

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    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.
     
  20. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    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.
     
  21. wowzone2009

    wowzone2009 New Member

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    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
     

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