Very Simple Switch for multiple leads

[oldcarguy85]

Hi There,
i have done some electronics work in the past, but i must admit it was all very hackish, (except for OBD2 LCD - Data Readout Tool - Digital Gauges - Home). Either way, i need to design a very simply circuit to switch some wires... here's the theory

I have a radio in my car. there are two devices (sirius radio and ipod unit) which use the same port on the head unit. they both can't be used at once. i want to design a simple circuity which will have both units connected to it, and at the flip of a switch change which unit is connected to the radio.

there are about 15 wires from each unit (same wires on both). So there is a lot of switching to be done, and obviously i would like to control this with one switch.

I'm not realyl sure where to start, i assume this would be done with some transistors.

Thanks for the help, and sorry for the probably very simplistic question,
Jordan

 

[Nigel Goodwin]

Use relays, far easier and more effective - you can get 4 pole change over relays easily, four of those would do it. Or you could use a simple rotary switch.

 

[philba]

what are wires that you want to switch? Everything? (ant, power, gnd, speakers...). You probably don't need to switch everything in that case. Also, if you switch power, you will lose all the volatile settings - like security code. I'd look at what you NEED to switch. You might get away with switching fewer wires.

 

[Boncuk]

Assuming that a "head unit" is a headset of speakers or ear phones you just need to switch the AF-outputs of the devices - left channel, right channel, ground.

You might use a rotary 3X4 (three input channels, four positions) switch limited to two positions (done mechaniclly with a retainer ring).

That kind of switch is available as a PCB mounted device and also for manual soldering.

Boncuk

 

[oldcarguy85]

thanks for the replies everyone. Ya i didn't even think about that, i probably should maintain all-time power to both units, and ground doesn't need to be siwtched, and probably switched power can go to both. Hmm there may only be a few communication wires. i'll have to check it out. so relay's are definetely the way to go then?

 

[Boncuk]

If your audio devices deliver car hifi at high power it's advisable to use relays and activate those with a switch, which only should toggle ON - OFF - ON, activating either relay.Don't forget to connect device grounds. If they are equipped with bridge amplifiers ground is not required.To make that sure better ask audioguru.This what the switching device could look like:Boncuk