technical diversions

a place to document my current project of connecting an iPod to a Saab 9-3 convertible with the factory audio system.

Wednesday, February 16, 2005

so you want one? (long post)

Now that i have it working for me i will dedicate some time to document this so other can follow and improve this.

This project can be divided in 3 parts:

1.- Add an AUX input to the factory radio. This can be phono stereo 1/8 jack or RCA type. The input will be for a "line level" signal but a signal from the headphone jack of your player will work, just be careful with the volume level. Adding this input uses part of the circuits and connectors used for the external CD changer. After this modification the external CD changer cannot be used (or installed). The modification is reversible.

2.- by doing part 1 you gain the AUX input, but you no longer can use the onStar/telephone interface in your radio. If you want to keep that functionality then you can use the circuit i designed. This circuit has these features:

* Ads two inputs to the radio, one is designed for the iPod, and the other if for any other audio device. The input is a phone stereo 1/8 jack.

* Keeps the onStar/telephone interface working normally. If there is a call in progress it will override any other input and the telephone signal will be feed to the radio, like the normal operation.

* Has a switch with three positions to control the iPod/AUX input: off, charge only and charge + play

* Small enough to fit inside the saab phone holder.

* Filtered, diode and fuse protected power supply for your iPod

This circuit is designed to use parts from the belkin car adaptor. The parts used are the iPod dock connector & cable and the amplifier. Even if not using the iPod, the amplifier on this adaptor is convenient because the signal level can be adjusted.

The circuit needs to be connected to: +12V accessory power (called +15 in saab terminology), ground, audio&ground from the onStar/telephone, TEL-MUTE signal from the telephone, TEL-MUTE going to the radio, stereo audio signal going to the radio

3.- Physically mounting the iPod. I used the saab phone holder and the belkin iPod carrier, using “pressure sensitive” double sided tape. I had to put three layers of tape on the top part and only one on the bottom part to give some clearance from the console while removing the iPod.

I have a first draft of the instructions for the part 1 ready. If you want to get it, please send me an e-mail. I will ask you for your feedback on this document. Please note that this requires some experience in working with electronics and some special tools. Once some people have done this i will post it here.

For part 2, i have parts to build 3 more circuits; depending on the interest i will probably sell them. I have not figured this out. Having the circuit is just the starting point, you need to mount it, a little plastic box will do it, or inside the saab phone holder. Also you need to wire it to the car, or take it to a car stereo shop to have it installed. Please provide me some input if will be willing to buy it from me, or rather have the schematics.

For part 3, beside some additional pictures i do not plan to do any more.


  • At 10 July, 2008 14:33, Blogger Edgaras said…

    Thank you for nice idea to use TELEPHONE input for line audio input. I've posted my experience with SAAB 9-5 MY-98, AS2:
    Best regards


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