Countdown Timer

Discussion in 'The Projects Forum' started by JoeBro391, Jun 1, 2010.

  1. JoeBro391

    Thread Starter Member

    May 15, 2010
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    Hello, i'm looking for any tips on building a generic countdown timer to work with a 7-segment display. I have a really decent knowledge of electronics and and Integrated Circuits, but I don't currently know of which IC might be best for this project. I've built a countUP timer with a 4026 and it was pretty simple and I know how to manipulate all of the connections for the most part. (there's no way to have the 4026 count down, right?)

    Anyway, I don't want to use any type of Microcontroller and/or PIC or anything like that (that's something I'm currently just starting to read into); I want to do this soley with IC's. I heard that the 4029 might be what i'm looking for, but I also heard that I'd need a 7-segment decoder IC (a 4511?) to use in conjunction with the 4029 and a 7-segment display. Does anyone know of any IC's (what are they called? dividers in this instance, i'll assume. is that a proper assumption??) that will basically work in an opposite manner than the 4026 and have outputs made to work with a 7-segment display??? Thanks. -Joe

    PS: let me know if you need any clarifications as to my intent if these brief paragraphs were unclear
     
  2. Zaraphrax

    Active Member

    Mar 21, 2009
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    You could use a 74HC192 (http://focus.ti.com/docs/prod/folders/print/cd74hc192.html) to do the timing (it supports counting up AND down), which gives the output in BCD. You'll still need a BCD -> 7-seg encoder as you mentioned. To my knowledge and from a quick Google search, I couldn't find anything that outputs it in 7-seg code.
     
  3. BMorse

    Senior Member

    Sep 26, 2009
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  4. JoeBro391

    Thread Starter Member

    May 15, 2010
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    what's the encoder for then , if it outputs in BCD?? Is it so the lights of the display aren't more dim when the digit reads "8' opposed to "1" (because of the extra segments on)??? Or is BCD something different?? Thanks

    BMorse: thanks man, i'll check that out

    -Joe
     
  5. Zaraphrax

    Active Member

    Mar 21, 2009
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    BCD and 7-seg code are something different.
     
  6. JoeBro391

    Thread Starter Member

    May 15, 2010
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    aaaahhhh...that makes sense now. What exactly is BCD?? -Joe
     
  7. bertus

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    Apr 5, 2008
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  8. beenthere

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  9. JoeBro391

    Thread Starter Member

    May 15, 2010
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    thanks guys! -Joe
     
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