[Noisebridge-discuss] Car Stereo Analog Electronics

[Mitch Altman]

Hey Matt,

I'm glad you found us!  There's lots of DIY-ers here.

Do you have a CD changer hooked up to your car stereo?  According to the comments under the Intro step on the instructables article you linked to, "From my understanding, you must have a CD changer installed for this hack."

You are correct:  all you need to do is connect Left and Right and Ground from your mp3 player to your car stereo.  But you have to get your car stereo to turn on its amplifier, and you somehow have to connect the mp3 L & R signals into the car stereo's audio amp input.  Evidently, the DIN connector only connects its L & R signals to the car stereo's audio input when a CD changer is plugged into it and sends some magical commands to the car stereo via the BUS pin.

If you don't have a CD changer, then you could open up your car stereo and poke around till you find the Left channel and Right channel inputs to the main audio amplifier, then play a blank cassette tape (if your stereo has a built-in tape player) or play a blank CD (if it has a built-in CD player).  Audio ground is just the metal case of the stereo.

The BATT pin on the DIN connector is 12v out from your car, according to the diagrams you found (both the instructables article and the nsxprime page you linked to match each other).  You can use the 12v output for anything you want.  But don't connect it directly to USB power unless you know it can handle 12v.

Headphones come with very cheap cables attached to them, which makes it very difficult to cut one off and then have access to the wires inside, so unless you are an expert at cabling, I'd recommend buying connectors and shielded audio cable and making your own cables (which isn't trivial, but is not very difficult with some practice).

Solder irons and all tools are available from Radio Shack, but better ones are available for a better price from Jameco:
http://www.jameco.com
Jameco also has shielded audio cable and connectors of all kinds.  But if you want a shitload of all parts available, there's Mouser and Digikey
http://www.mouser.com
http://www.digikey.com
All three of these companies ship anywhere in the world for an OK price.

Happy travels,
Mitch.


--------------------
> From: matt.price at utoronto.ca
> To: noisebridge-discuss at lists.noisebridge.net
> Date: Wed, 28 May 2008 07:11:22 -0700
> Subject: [Noisebridge-discuss] Car Stereo Analog Electronics
> 
> hi folks,
> 
> i posted the note below to the sf-lug group and kristian suggested i post it here instead!  glad to learn about this greoup -- very cool idea -- and also hope you can help me out!  thanks,
> 
> matt
> ---
> 
> hi guys,
> 
> well, this is the DIY group i know best...  I'm getting ready for a big
> road trip (all the way back to toronto) and I'm trying to hook my ipod
> up to my car stereo.  unfortunately i have a stock honda civic stereo
> head unit, which doesn't have an aux in anywhere.  instead htere's a
> proprietary DIN-style connector that goes from the head unit (which has
> a radio ) and the external cassette player (mounted separately in a
> different spot on the dash).  
> 
> there's a pin diagram for this connector here (well, at least i think
> it's the right diagram):
> http://www.nsxprime.com/FAQ/DIY/sound_system.htm
> this instructables suggests it's the same as the honda stereos:
> http://www.instructables.com/id/SOU74LJF9056P3L/
> 
> my plan is to take out the  cassette player (not hard, i've done it
> before), and somehow splice an audio out cable into the din connector.
> as far as i understand it, all i need to do is connect the signal
> ground, left and right wires to the appropriate pins, and the thing
> SHOULD get sound from the ipod (or any aux connector).  i see two ways
> to do this:
> 
> 1) just take an old headphone wire, open it up, and run the individual
> wires into the appropriate din pin openings.  but this is too simple.
> 
> 2) find an 8-pin din connector, solder the wires from the headphone jack
> into it, but also maybe somehow use the other wires to do other things.
> for instance, i'd love to get usb power off of the battery; i'd love to
> be able to somehow control the ipod using the accessory; etc.  i dont
> know how ocmplicated all of these are.  also all my soldering tools and
> stuff are back home in toronto.  and finally, i don't know where to buy
> stuff like this here in sf.  
> 
> sooo...  i'm hoping there's someone out there who knows all this stuff!
> or who knows where to point me for more info.  i'd lvoe for this to
> work, it's gonna be a looooong car ride...  thanks!
> 
> matt
> 
> 
> -- 
> Matt Price
> matt.price at utoronto.ca
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> Noisebridge-discuss mailing list
> Noisebridge-discuss at lists.noisebridge.net
> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
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