airborne_cookie

This isn't a question specific to carputers but I intend to install this system alongside my computer.

How can I make it possible to have four inputs (in this case, two way radios, transeiver and a scanner) to feed into a single speaker mounted under the dash.

The system must be configured so that if there is activity from input 1, it will override that from 2, 3 and 4. If 1 is quiet but 2 is active it will override anything from 3 and 4, etc.

The best idea I can think of so far is to rig up a system using audio type relays triggered by a wire tapped into the LED showing the radio is receiving.

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psyrex

So that numbering will also be a priority list? I don't know any product that does that, but you can probably make your own circuit. I can help you with schematics, but I'm in the middle of midterms right now so all I have time for right now is to offer some pointers. For example, at the bottom of this page is an interesting way to detect if there is audio and then do something with it: http://www.doctronics.co.uk/4016.htm. Have a couple of these and a simple truth table, and you've got your 4 way audio switch with priority switching.

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Gen 1: Pentium 3 1GHz - ATX - 2005
Gen 2: Pentium M 1.6GHz - ITX - 2006
Gen 3: Pentium M 2.0GHz - 5.25" SBC - 2007
Gen 4: (coming soon: Core2 Duo - 3.5" SBC - 2009)
...it never ends

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