[HELP][RENEW]Traffic Lights

Discussion in 'Homework Help' started by nubpwn3r, Nov 17, 2015.

  1. nubpwn3r

    Thread Starter New Member

    Oct 15, 2015
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    soo after some help from you guys I have made the project and it was working smoothly
    we showed it to our professor but he was not pleased, he recommended that we redo it so that GREEN HAS A COUNT OF AT LEAST 10, RED ALSO 10 AND YELLOW 3.

    the seven segment display should behave so that when for example: Green counts down from 10 to 1, after 1, it resets back for the next duration of the next light which is yellow with a count of 2, then comes red after the 1 count of yellow

    so the 7 segment display should show something like this:
    Green: 10 9 8.......2 1 ~> Yellow: 2 1 ~> Red: 10 9...... 2 1 ~> Green.... cycle back

    Our current project is a traffic light with a countdown of 9 to 0 Green count of 4. Red count of 4. and yellow count of 2.
    Using 74192 as the clock 0 to 9. connected to 7447 and is then conneted to 7 segment display
    • For the lights red green yellow, we used CD4017BE decade counter and each output is connected to a LED

    our professors recomendation is found above in bold:

    thus we need to use two seven segments for the 2 digit count for red and green LED

    -my problem is how do i do that im currently thinking of JK F/F as a 5 bit modified countdown BUT i think its impossible to put it into a 7 segment decoder with 5 bits

    -another thing i can think of is using multiplexers, but the only available multiplexer here is 4 to 1

    other than these things, i am clueless

    need help pls


    Edit1: added condition i forgot to post awhile back about the 7 segment behavior
     
    Last edited: Nov 17, 2015
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    There are chips like the CD4510 that can be cascaded together. The clock pulse goes into the first one (ones digit) and that puts out a binary-converted-decimal (BCD) output. After a binary 9, the count rolls over to 0 AND, there is a special output that sends a clock pulse out to the next cD4510 in the cascade.

    You can put together as you want. The good news, you can count UP or Down.

    Google datasheet - CD4510.

    The output of each of these chips can then go to a CD4511 (decodes the BCD output to a 7-seg display) which drive a 7-segment LED
     
  3. nubpwn3r

    Thread Starter New Member

    Oct 15, 2015
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    ty for urgent reply really appreciated it
    ahhhh i get the point but that would only make a bigger scale of our project

    the seven segment display should behave so that when for example: Green counts down from 10 to 1, after 1, it resets back for the next duration of the next light which is yellow with a count of 2, then comes red after the 1 count of yellow

    so the 7 segment display should show something like this:
    Green: 10 9 8.......2 1 ~> Yellow: 2 1 ~> Red: 10 9...... 2 1 ~> Green.... cycle back

    im a bit at fault for forgeting to include that condition in my post, gonna make an edit right away
     
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Are you sure the count has to be 10 to 1? Counting from 9 to 0 is also a ten count. Only needs one 7 segment display.
    Per GopherT's post, the 4510 can be configured to count down. Then a decade counter can count to which color should be displayed. Look up the data sheet for a 4017.
     
  5. nubpwn3r

    Thread Starter New Member

    Oct 15, 2015
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    what i am trying to say is that the countdown for the light green / red should be 2 digits sooo it should be at least 10 which is a two digit number
    other details can be found in my previous posts.

    that was our first design for the traffic light, a 9 to 0 count but yea professor made revision sad
     
  6. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Our comments still apply then. But you'll need two 4510s and more glue logic...
     
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