Pushbutton mutually exclusive selection of 1 of 3 audio inputs


I'm needing some help realizing a method to implement the following:

1 room.

Three locations to connect an audio player via 3.5mm jack on single gang wall plate.

The idea is that I'd connect an audio player's 3.5mm plug into any wall plate and listen.

All audio processing/ amplification equipment is located remote from the room. Audio volume is dependent on player output.

Can't just have all input plates go to a mixer cuz each channel's volume would need to be up all the time and there'd be a connection noise as the 3.5mm plug entered the jack

I've seen a contact closure controlled audio switcher: a spst switch would need to be at each wall plate, connected to the control pin that affects that particular input.

I'd rather there be a momentary contact pushbutton (preferably lighted (or separate LED) while that input is active.

Am wondering if this project is a candidate for arduino..??

Or am I better off just using relays somehow? Any info appreciated.



It sounds a reasonable idea. I am wondering if there's a clever way to remote-sense the jacks' presence - perhaps a high-impedance DC bias added to the audio lines, you sense when the voltage reduces to closer to ground to indicate a jack being inserted, wait a couple of seconds and then switch to that channel.

The Arduino would then monitor the several signal sources for the DC bias and drive the signal switches. Something like a 1M resistor or even higher could provide the bias which would be totally dominated by a real signal source.

Do you have a plan on how to do the actual signal switching?

Hi Mark-

Thx for reply.

Audio switching could occur via Extron switcher which uses otherwise unused pins on a DB9 serial connector to connect to contact closures.

I am unfamiliar with the DC bias stuff you mentioned.

Of course it would be cool to auto-sense when a plug is inserted.

Can you elaborate on that concept? When I think of DC in audio path I am wary.



The idea is only an idea. DC offset could cause clicks on unplugging - that's why I'd go for very high impedance pull-up. On plugging in the large click of draining the offset would be inaudible because the circuit is disconnected at this point. On unplugging the offset only rises slowly as the input capacitor of the amplifier starts to charge, so only a quiet click (I'll assume the amplifier has DC-blocking circuit).

It could be a little tricky to get it to work well... a jack socket with a plug-presence detect switch would be a simpler and more robust solution.