Hello everyone!

I have a little issue that I'm hoping you guys can help solve.

I use headphones to listen to music from my phone.

I would like to come up with some sort of automatic switching device that will allow me to use the phone and handheld radio with the one pair of headphones.

Basically, I will be listening to music, and when the handheld receives audio, the switch will disconnect the phone, and connect the handheld to the headphones.

That way I can be listening to music, and still be able to monitor/listen incoming audio on the handheld radio.

So, basically 2 sources of audio, one output (headphones).
Switch selects the music source as priority, and only switches to handheld audio when there is audio there.

Notes:
Perhaps the power for the switch can be obtained from the microphone jack of the handheld radio. I think it has a few volts on one of the pins of that jack.

It is a regular Midland brand LXT440 model.

Thanks for the help!!

 

If you want this to happen automatically, use a comparator to detect which channel starts to play music and then use an analog multiplexer IC to choose which channel will feed the headphones.

 

Ok, using your suggestion and a quick search, I found this:

MAX4765 - dual SPDT analog switch qith built in comparator and shunt switch.

http://www.chipcatalog.com/Doc/D5DC74D51F228C707C0CD589BA93DE0B.pdf
Page 8


Would that be a good fit for what I'm trying to accomplish here ?
My only concern is the package.
Is there something like that in a through-hole package ?

Thanks!

 

Yes, it looks good for what you need. If you look at page 8 you will see a diagram of what you want to do. I have never used such IC so I don't know if they exist in DIP packages. Search more.

 

Yes, it looks good for what you need. If you look at page 8 you will see a diagram of what you want to do. I have never used such IC so I don't know if they exist in DIP packages. Search more.

Yeah, I saw page 8.
I referenced it in my post above, with the PDF link.

The comparator would be wired a little different I guess.
Instead of a mute switch, its output would be used to control the switch, and the input would be the audio source from the handheld radio.

I think...

 

Would there be a way to do this with a passive circuit somehow ?

 

Would there be a way to do this with a passive circuit somehow ?

A passive circuit contains only resistors, capacitors etc but not switching devices, so the answer is no.