Switch source when 3.5mm jack is connected

[kenny782]

I have 2 sources in my car to connect to one stereo.
Source 1 is hard mounted
Source 2 is whatever I want to plug into a 3.5mm jack

So I want source 1 always connected to my stereo except when I connect to that 3.5mm jack.

Since I have 12V available I was thinking of a 3.5mm jack/isolated switch and a DPDT relay. But I was too worried about blow up my PDA/ipod.

I've been looking for a 3.5mm jack with a DPDT switch. I found companies that make them but nobody that sells them.


If anyone has any ideas I'd really appreciate it.

Thanks,

Kenny

 

[canadaelk]

Well, if we would know where you are, maybee someone could help you! E

 

[carbonzit]

So you're going to end up with something like this:

**broken link removed**

The relay is not going to be a problem. But if there's any place where the danger of getting 12 volts into your iPod is, it's at the jack. So it would pay to get a decent-quality jack, and definitely test it before plugging anything into it. Just put a plug in and put a voltmeter on both contacts and make sure you read zero volts there.

If you're still worried about this, you could put two capacitors in after the jack signal lines to isolate it in case something goes wrong. 10 µF ought to do it (you can get non-polarized caps if you're concerned about them being reverse-voltaged).

 

[Mr RB]

Have you tried Digikey? Those DPDT switched stereo jack sockets are not that rare.

 

[carbonzit]

Sure 'nuff, like this one (it's a PC-mount type, but otherwise should work for you). It's not DPDT, but does have 2 sets of switch contacts, so it will do what you want it to do without needing a relay.

 

[kenny782]

So you're going to end up with something like this:

**broken link removed**

The relay is not going to be a problem. But if there's any place where the danger of getting 12 volts into your iPod is, it's at the jack. So it would pay to get a decent-quality jack, and definitely test it before plugging anything into it. Just put a plug in and put a voltmeter on both contacts and make sure you read zero volts there.

If you're still worried about this, you could put two capacitors in after the jack signal lines to isolate it in case something goes wrong. 10 µF ought to do it (you can get non-polarized caps if you're concerned about them being reverse-voltaged).

Thanks for the diagram and definitely the safety tips

Have you tried Digikey? Those DPDT switched stereo jack sockets are not that rare.

Yeah tried digi and everywhere else I can think of

Sure 'nuff, like this one (it's a PC-mount type, but otherwise should work for you). It's not DPDT, but does have 2 sets of switch contacts, so it will do what you want it to do without needing a relay.

I looked at that one yesterday actually but I couldn't think of anyway to make it work for this application.
But then again I'm better at assembly than design.

Thanks guys

-Kenny

 

[carbonzit]

Well, since this is the schematic of the jack:

**broken link removed**

all you gotta do is connect the outputs of your "hard-mounted" source to 4 & 5, and connect the inputs of the stereo to 2 & 3. When you plug in your portable device, it opens the switch contacts and connects the source to the input.

 

[kenny782]

Well, since this is the schematic of the jack:

**broken link removed**

all you gotta do is connect the outputs of your "hard-mounted" source to 4 & 5, and connect the inputs of the stereo to 2 & 3. When you plug in your portable device, it opens the switch contacts and connects the source to the input.

oh ok, cool
Maybe in my next life I won't be an idiot lol

Thanks alot!

 

[carbonzit]

Maybe in my next life I won't be an idiot lol

That's what I keep telling myself ...

 

[kenny782]

lol, just ordered the stuff from digi