I found this interface chip:

http://www.modulestek.com/MB-C05.php

Datasheet here:

http://www.modulestek.com/DOC/MB-C05_SPEC.pdf

The point is to hardwire a Bluetooth A2DP audio receiver into the OEM headunit with AVRCP, which would allow the headunit to control the player itself. It also supports the handset/handsfree Bluetooth profiles, which means it would pause your music and you could answer phone calls and such.

My cell phone supports all this (A2DP, AVRCP, handsfree/headset profiles, etc), so this would be the ultimate solution. Walk in the car, switch the headunit to changer input, and skip tracks as you would a CD changer. Pause the music when a call comes in, answer it handsfree.

Who wants to tackle it?

 

There are already many off the shelf head units that will do this. Why would I spend the time and money to develope this when for under $200 I can replace the head unit with bluetooth built in, better sound than stock, and with less engineering than you are talking about, have the stock remote buttons work just as well as stock?

Just not worth the effort.

 

He is right. you have a bluetooth component that you woudl include into another board that you have preconstucted or system that you are going to add bluetooth to.

You are better off purchasing a new HU with the bluetooth technology integrated.

 

I understand what he is saying about making it a CD Interface device, but if the head unit is not actively seeking the changer input, the phone calls go unanswered. The other problem is that the stock head unit just simply sucks. There is a company called CarPC I believe that makes a computer interface that replicates a CD changer signal. The music files on the PC are cycled as if they are in the CD changer. If you had that you could simply add a USB bluetooth to your laptop and some programming later your phone rings into your stereo, again only if your head unit is actively looking at the CD changer port.

And you would still wish you had a better stereo after all is said and done.

 

Are you going to reinvent the wheel while you're at it?