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Heart-shaped badge

  1. Jul 6, 2011 #1
    hi... am actually doing a project entitled' Heart-shaped badge'... it uses 8 LEDs and ICs: 4017 and 555 timer...

    the LEDs chase clockwise....

    and now i have to make them chase anti-clockwise and also make a two-way chasing effect...can anyone help me with these? am kinda stuck...
     
  2. jcsd
  3. Jul 6, 2011 #2

    berkeman

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    Staff: Mentor

    Welcome to the PF.

    Show us what you have so far. We won't do your project for you, but may be able to offer a hint or two if you show us all of your work.
     
  4. Jul 6, 2011 #3
    i've already mounted the circuit on breadboard...

    I can not understand how to make the LEDs chase in the anti-clockwise way..

    thank you for helping..
     

    Attached Files:

  5. Jul 6, 2011 #4

    berkeman

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    Can you post your schematic, and explain how it works currently?
     
  6. Jul 6, 2011 #5
    It's as shown below


    http://www.kpsec.freeuk.com/docs/heart.pdf [Broken]
     
    Last edited by a moderator: May 5, 2017
  7. Jul 6, 2011 #6
    when the switch is closed, the 555timer sends a pulse to the 4017. one LED is lit at a time and then it chases around in the clockwise direction.
     
  8. Jul 6, 2011 #7

    berkeman

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    And what is your explanation for how the circuit works? Have you looked at the 4017's datasheet (you should)? How is it able to decode the count to make the LEDs light in that order? Is there anything in the datasheet that would indicate it could count the other way?

    What exactly is your assignment statement? What if the 4017 is not the right chip to use? Is there another chip that might work better?
     
    Last edited by a moderator: May 5, 2017
  9. Jul 6, 2011 #8
    no the 4017 is the right chip and yes i've gone through the datasheet. the 555timer has a count from 1 to 9 and that's why it goes in a clockwise direction. i do not know how to make it start from 9 to 1.

    the assignment is to make a heart shaped badge. first we implement using breadboard and then on the vero board. we implement it as it is and then we modify it making the LED start lighting up in two directions.
     
  10. Jul 6, 2011 #9

    berkeman

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    The 555 has no count. How does the 4017 work in this application?
     
  11. Jul 6, 2011 #10
    The 555timer sends a pulse to the 4017. The 4017 then steps the output from negative to positive in a series of ten steps, with only one pin being on at a time.

    the 4017 counts up to a certain number and then restarting the count.
     
  12. Jul 6, 2011 #11

    berkeman

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    Good! But do you see any option for changing the up-count of the 4017 to a down-count? I don't see one at first glance...
     
  13. Jul 6, 2011 #12

    berkeman

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    I can think of at least one way to do it, but it involves a 10x3 header...
     
  14. Jul 6, 2011 #13
    can you make it clearer?
     
  15. Jul 6, 2011 #14

    berkeman

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    Not yet. What is the exact project statement? What flexibilities do you have? Are you sure you have to use the 4017 for both parts of the project?
     
  16. Jul 6, 2011 #15
    the schematic circuit i showed you is given. but modifications have to be done in order to do that two-way chase. and the 4017 is to be used.
     
  17. Jul 6, 2011 #16

    berkeman

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    Well, there may be a way to do it electrically, but I'm not seeing that yet. I would do it mechanically, if that's allowed as part of the project statement.

    Can you think of mechanical ways to do it?
     
  18. Jul 6, 2011 #17
    i can't see a way.
     
  19. Jul 6, 2011 #18
    The 4017 doesn't have an option to "count down". You will have to add some components to do it. You could wire each LED in a CW and CCW direction, and use 8 switches to control it. This could be as simple as using a multiplexer-type device to switch between the CW/CCW wiring schemes.
     
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