I'm busy with modifying one of my previously made boards, and came across one question.
Right now this part of the circuit does a simple thing: SPDT switch changes channels of output. Signal (0-5V).
--Above example in the drawing--
What I would like to do is: to keep this functionality, but add a possibility to send a simple on/off state to Arduino, so Arduino would know what channel is running at the moment.
Of course would be easy to use DPDT switch instead, but thats not an option because all SPDT switches are already soldered on PCB. So I can only route those switches via relays (I have no other option in my mind right now). It's a modular thing, all switches are on one PCB and the rest of the circuit on the other PCB, I can basically manipulate anything that is between those.
And my question: is there any voltage drop via relay? Because the voltage of the signal is critical. It is musical stuff and basically it controls notes on the other end. 1V per Octave. It means that notes are changing every ~0.084V
Any other option?