Tone Reader

Discussion in 'The Projects Forum' started by andyman, Feb 8, 2009.

  1. andyman

    Thread Starter New Member

    Jan 19, 2009
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    I'm looking for a 'tone reader' circuit that will read different tones (1000hz, 900hz, etc) from an audio source (line in) and return a separate On current for each tone.

    Thanks,
    Andy
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You could use filters for the tones like in this equalizer circuit.
    http://sound.westhost.com/project75.htm
    Afther each filter you could place a rectifier that gives you the intensity of the tone.

    Greetings,
    Bertus
     
  3. andyman

    Thread Starter New Member

    Jan 19, 2009
    7
    0
    Thanks for the info, Bertus.

    Forgive my ignorance, I'm somewhat new to electronics - on the schematic you referenced - where would I connect my audio line in? The VE inputs?

    Andy
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    The line marked "IN". +VE and -VE are the positive and negative power supply rails. Ground is common to both power supplies and to the signal.
     
  5. Søren

    Senior Member

    Sep 2, 2006
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    Filters won't discriminate well enough for such close tones. Tone decoders like the LM567 should be used.
     
  6. andyman

    Thread Starter New Member

    Jan 19, 2009
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    Do you know of any schematics for the LM567?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    Google it, and get the data sheet.

    As another suggestion, there is the old twin-T filter that can't be beat for tight response. You can Google those, too.
     
  8. fred_uk

    Active Member

    Jan 3, 2009
    67
    0

    hi

    i have just been looking at the project, could you tell me where you would connect the led?
     
  9. bertus

    Administrator

    Apr 5, 2008
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    Hello fred_uk,

    What you are doing now is hyjacking the thread.
    But you can place a rectifier at the output of the filter.
    Amplify the signal (and if you want send it through a comparator) and you can trigger a led.

    Greetings,
    Bertus
     
  10. andyman

    Thread Starter New Member

    Jan 19, 2009
    7
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    My ultimate goal here is to choreograph fireworks. I already have a wireless control box with hardware switches. I want to put tones (at least 8 different ones) on the right channel of my audio track, and feed that track to an interface which would translate the various tones into 8 different relay closures.

    Andy
     
  11. fred_uk

    Active Member

    Jan 3, 2009
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    sorry bertus ;)

    think this would be ideal for my application, is that pin 7?

    sorry to hijack :eek:
     
  12. bertus

    Administrator

    Apr 5, 2008
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    Hello fred_uk,

    Here is another page from that site.
    http://sound.westhost.com/project63.htm

    It gives more details on how to configure the filters.
    The output of the filter is on pin 6 of the opamp (when using a single opamp).
    The output is on pin 1 or 6 when using a dual opamp.

    Greetings,
    Bertus
     
  13. fred_uk

    Active Member

    Jan 3, 2009
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    bertus your a very clever chap! :D:D:D
     
  14. bertus

    Administrator

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  15. andyman

    Thread Starter New Member

    Jan 19, 2009
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    The audience won't hear the tones. This idea might work. I'll let you know how I make out.

    Thanks for the input, guys.
    Andy
     
  16. AlexR

    Well-Known Member

    Jan 16, 2008
    735
    54
    This sounds like a job for DTMF encoder and decoder chips. They will give much better detection reliability than single tones and filters. Off hand I can't remember chip numbers but a google should throw up some likely candidates.
     
  17. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    I have to second (or third ;)) the notion of DTMF, as I have seen quite competent huge X-mas "decorations" made that way.

    If needed, I can provide the DTMF tones as wave files, MP3 or whatever, so just the decoder will be needed.
     
  18. andyman

    Thread Starter New Member

    Jan 19, 2009
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    0
    Thanks for the offer, but I may be able to generate them myself. I have an Audio Editor (Audacity) that can generate tones as sine, square, or sawtooth wave - will that work? If so, which one?
     
  19. bertus

    Administrator

    Apr 5, 2008
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  20. Søren

    Senior Member

    Sep 2, 2006
    472
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    Hi,

    Audacity cannot generate DTMF (Dual Tone Multiple Frequency) and the link that Bertus gave you, cannot save the tones, as far as I can see - but you can fetch this zip with 300ms DTMF files.
    I have made them at 0dB and at -6dB.
     
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