electronic volume control circuit. is there something like this?

Dgswaner

I want to control the volume and possibly the gain of an speaker AMP. from the controller, automatically.

I had a thought, find the right resistor photo transistor combination to get the range required. (0 - 5k) have the photo transistor enclosed in a light proof box with an led. I could control the brightness of the LED through a PWM pulse, and subsequently the resistance of the photo transistor.

am I reinventing the wheel? is there a better way of doing this? is their a circuit component better suited for this?

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

kjennejohn

Here is a Microchip search result for their digital potentiometers:
www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1999&ty=&dty=&section=&NextRow=&ssUserText=digital%20pot

I didn't readily see anything about audio tapers. It looks like they are linear progression. Anyways, these talk to the processor through serial communications, like SPI.

Hope this helps,
kenjj