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I'm needing a crude VU meter for line level audio — Parallax Forums

I'm needing a crude VU meter for line level audio

CannibalRoboticsCannibalRobotics Posts: 535
edited 2010-03-30 21:56 in Propeller 1
I've got a few spare prop ports and I'm looking for a good way to indicate audio activity at a line level. It does not have to have any unit significance. I just want to drive a handful of LED's for troubleshooting purposes.
I'd like to minimize the number of external components.
Line level is roughly 0 to 1v, 60Hz would be an adequate sample rate. I could smooth the audio via an RC arrangement.
Ideas?
Jim-

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Comments

  • James NewmanJames Newman Posts: 133
    edited 2010-03-30 17:58
    Ummm... maybe a homemade adc via opamp/resistors?

    If you just need a boolean, just amp it up and use the prop to do some timeout since last activity type logic. (Minimizing external components... should be easily doable externally though)
  • SciNemoSciNemo Posts: 91
    edited 2010-03-30 19:27
    I seem to remember somebody making a VU meter with propBASIC. I believe the code was in the main thread for pBASIC. I tried it on the demoboard and it worked fine, so it might be worth taking a look at. I don't have a link, but maybe somebody else has it bookmarked.

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  • jknightandkarrjknightandkarr Posts: 234
    edited 2010-03-30 19:47
    I got a scematic using lm3914's i know it works, I've used it

    Joe

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  • BeanBean Posts: 8,129
    edited 2010-03-30 20:04
    Here is the PropBASIC sound meter program.

    It is written to run on the Demo board.

    To run it stand-alone, you just need to built the ADC circuit (2 caps, 2 resistors).

    It needs two pins to do the ADC function, and you'll need pins for however many LEDs you want.

    Bean.


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    Use BASIC on the Propeller with the speed of assembly language.
    PropBASIC thread http://forums.parallax.com/showthread.php?p=867134

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    Post Edited (Bean) : 3/30/2010 8:56:06 PM GMT
    pbas
    pbas
    sndmeter.pbas
    2K
  • CannibalRoboticsCannibalRobotics Posts: 535
    edited 2010-03-30 21:56
    Very Cool! Thanks all.
    Jim

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