calling all experienced builders !!

Discussion in 'The Projects Forum' started by rjsbasso, Sep 13, 2010.

  1. rjsbasso

    Thread Starter New Member

    Sep 13, 2010
    2
    0
    hi,

    i am looking to build a circuit that takes an audio 3.5mm jack, and filters the frequencies so that it sends a small electric impulse when it registers a certain frequency. ideally over 3 octaves, i'd have a circuit that could tell when 36 different frequency ranges are being played. (probably 4 or 5 octaves now that i think about it, so 48 or 60 different ranges)

    or would it be easier to write a program that does this, and then somehow have my computer send the impulses via a more simple circuit?

    is this even feasible?

    i do not have much experience with circuits but i do know how to solder.
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,156
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    IMHO, you'll be FAR better off using software on a computer than trying to devise your own circuit (design, test, build, etc. - a LOT of work). If you look around, there may be software that already comes very close to what you want. I'm thinking of a graphic equalizer display that shows the relative volume of a number of frequency bands. You want a lot of bands, but there are some pretty sophisticated sound analysis tools out there.

    IF you get skunked and cannot find exactly what you need, only then would I start looking into building my own solution. I'd start with the open source community if it becomes necessary to do some programming. You might find someone that is already close.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    I agree with wayneh.

    Check out mik3's blog and videos. He built an LED audio spectrum analyzer using a PIC18.
    Link: http://forum.allaboutcircuits.com/member.php?u=17813
    Source code for the PIC is in his blogs.

    The learning curve for uC's is a bit steep, but the use of them eliminates most of the components that would otherwise be required.
     
  4. rjsbasso

    Thread Starter New Member

    Sep 13, 2010
    2
    0
    thanks! although i have no clue what to do with the code.

    is there any literature on the web that could help me figure out what to do with the code? or maybe something that can help me understand what's going on in the first place wth the code...i don't really know what uC is and i have a loose grasp on FFTs
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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  6. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Almost sounds like something you'd see incorporated into professional MIDI processing software.
     
  7. wayneh

    Expert

    Sep 9, 2010
    12,156
    3,063
    Yup, that's my point: there are a lot of wheels out there and there's no need to invent another. I'd start by exhaustively searching existing software for what I need. For all I know you can already do what the op wants in GarageBand.
     
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