Reading values from LM386

Discussion in 'The Projects Forum' started by keithg, Sep 30, 2009.

  1. keithg

    Thread Starter Active Member

    Jan 17, 2009
    I am designing a noise monitor for our school cafeteria that will behave somewhat like a typical VU meter but without the immediate cascading up and down. If possible, values taken from an LM386 will be fed to my Arduino for establishing thresholds that will light LED's. How do I read values from the LM386? I have tried a variety of components with no success. I would appreciate advise.
  2. Audioguru


    Dec 20, 2007
    The output of the LM386 swings from +1V to the supply voltage -1V at clipping.
    If you use the output coupling capacitor then its output swings above and below 0V.
    When the output of the coupling capacitor swings below 0V then it destroys the input of your micro-controller.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    Search on "LM3914" on this site. The IC might do what you wish without the uC.
  4. bountyhunter

    Well-Known Member

    Sep 7, 2009
    If you mean you need to monitor noise levels, Radio Shack used to sell a cheap but useful handheld portable SPL meter that runs on a 9V battery. I have one, they used to sell for about $30. Already calibrated in both A and C weighting and has ranges all the way up to 140 dB.