An idea I need help with

[Joel Sandler]

I have a GPS unit with an audio output (stereo) and a car stereo with a
GPS/Phone input. The GPS input is switched thru the ground, when the ground
is opened the audio mutes and the GPS audio is played over the speakers.
How can I create a switch the senses the audio, opens the ground and allows
the audio thru?

Any help is appreciated.

 

[Joel Sandler]

Tap tap tap? Anyone?

 

[Sir Charles W. Shults III]

It sounds like you want the GPS audio to be sensed and allow it to key
itself through- is this correct?
Look at VOX circuits. They key on voice. Wire the GPS audio output to the
input of the VOX circuit. Use a capacitor to couple it to maintain isolation.
The output of the VOX can then be used to drive any relay, given a small
transistor. That relay can then be wired to break your ground connection.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip