Intercept analog signal as required

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wackywired135:
I'm working on a project where there is what is essentially a variable voltage divider for 6 buttons. I can read the value of the signal by connecting the signal wire between a pull-up resistor and an analog pin on my Arduino. Normally, that signal wire is connected to another device which I don't know anything about, other than that it also is capable of reading the analog signal.

What I'd like to achieve is "intercept" the signal with the Arduino when other external input is received (serial, another button, etc) and be able to "reconnect" the signal wire to the other unknown device as needed. Sort of like an SPDT switch or relay, except those are bulky and inefficient. Could a pair of transistors or equivalent be used to change the path of the signal?

You want to muck about with a signal you know nothing about that is controlling an device you know nothing about and you think you can design something to do something with that unknown signal that will have no effect on the operation of that unknown device.

Does that seem rational to you?

Paul

You might want to use a 4066.

That looks like a steering wheel audio control and I suspect you are putting those resistors in - will almost certainly mess up the existing workings of the car stereo .

zwieblum:
You might want to use a 4066.

No chance of success. The 4066 is ancient part with horrible resistance specs. Fine for pure voltage, will not work as part of a voltage divider.

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