Simple audio signal to level convertor?
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Posted by Kasterborus on July 1, 2008, 1:15 pm
Please log in for more thread options I'm looking for a circuit that can read a standard line level audio signal and output a continous voltage 0-5v proportional to the amplitude of the input. This in turn would be read by an ADC/microprocessor to modulate some flashing lights. As always - any help is greatly appreciated. Dave | ||||||||||||||||
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Posted by christofire on July 1, 2008, 3:41 pm
Please log in for more thread options Try Googling 'precision full wave rectifier'. | ||||||||||||||||
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Posted by Peter Bennett on July 1, 2008, 9:43 pm
Please log in for more thread options On Tue, 1 Jul 2008 10:15:55 -0700 (PDT), Kasterborus
>Hi,
> >I'm looking for a circuit that can read a standard line level audio >signal and output a continous voltage 0-5v proportional to the >amplitude of the input. > >This in turn would be read by an ADC/microprocessor to modulate some >flashing lights. > >As always - any help is greatly appreciated. > >Dave Google for "colour organ" (or "color organ") or "Light organ" -- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca | ||||||||||||||||
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Posted by Bob Masta on July 2, 2008, 8:03 am
Please log in for more thread options On Tue, 1 Jul 2008 10:15:55 -0700 (PDT), Kasterborus
>Hi,
> >I'm looking for a circuit that can read a standard line level audio >signal and output a continous voltage 0-5v proportional to the >amplitude of the input. > >This in turn would be read by an ADC/microprocessor to modulate some >flashing lights. > >As always - any help is greatly appreciated. > If you are going to use an ADC and microprocessor anyway, you might want to consider letting them do more of the work. You could provide a preamp to get the signal in range of the ADC, and let software do the rest. That way , the software can handle attack/decay time constants, and most importantly it can do FFT spectral analysis to get frequency information, if you later decide you want it. Of course, this will mean that you will need to sample at a much higher rate and deal with the flow of data. You don't mention the capabilities of the uP you have in mind... can it handle this kind of workload? Best regards, Bob Masta DAQARTA v4.00 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Sound Level Meter FREE Signal Generator Science with your sound card! | ||||||||||||||||
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Posted by Bob Eld on July 2, 2008, 7:01 pm
Please log in for more thread options
> Hi,
> > I'm looking for a circuit that can read a standard line level audio > signal and output a continous voltage 0-5v proportional to the > amplitude of the input. > > This in turn would be read by an ADC/microprocessor to modulate some > flashing lights. > > As always - any help is greatly appreciated. > > Dave Since you are going to ADC it anyway, simply capacitivly couple the audio signal into the ADC. Insure that the max peak of the audio signal is within the ADC range. Convert to digital then detect and hold the maximum values for a determined length of time. Use the numerical value in this hold register to control what ever. Each converted value is compared with the previously held value and updates the held value if larger. A timer starts or restarts on each hold update. The register is cleared on the expiration of the timer. This creates a running peak of the audio signal. The peaks values of most audio signals will be emphasized in the bass region. This can be tailored with simple filtering if needed which isn't likely. | ||||||||||||||||
>
> I'm looking for a circuit that can read a standard line level audio
> signal and output a continous voltage 0-5v proportional to the
> amplitude of the input.
>
> This in turn would be read by an ADC/microprocessor to modulate some
> flashing lights.
>
> As always - any help is greatly appreciated.
>
> Dave