Stereo Mute & Mobile Phone

squarehead · August 10, 2005

Well yesterday I finally plucked up the courage to wire up my Nokia Carkit to mute my stereo when receiving and making calls.

I would like to say that I s*****d myself when I unplugged the stereo wired the yellow mute cable to pin 4 on the stereo (blue and orange cable) and plugged the connector back into the back of the stereo and the cd player started making a shuffling sound for about 30 seconds. I think this was a hard reset? Anyway it has been great since.

Anyhoos, it is working brilliantly, I would like to thank Duncan for providing the pin-out colour (in another forum) and Scarface for his contribution as well (in another search I did).

If your thinking of doing this I would advise you to do it, I am no electrician and managed to wire up the mute cable no problems. In hindsight I did cut the cable and use plugs to wire the cables together but I don't think you need to do that as there is sufficient space to plug the yellow mute cable in directly into pin4 (I would recommend you use a hard cable to do this (household electrical type) as it is much firmer to plug in.

Anyway, hope that all makes sense - now I will never miss a call!

Shame it doesn't pause the CD player though, well can't have everything!

Cheers guys!

MrADeveci · August 10, 2005

Glad to have been able to assist !

Enjoy

derekyau · August 10, 2005

Now work on the ignition sense as well, so the car kit powers on when you turn on the ignition... or have you dared that one already?

D.

MrADeveci · August 10, 2005

Now work on the ignition sense as well, so the car kit powers on when you turn on the ignition... or have you dared that one already?
D.

←

I know how to do that ..... obviously, but I'm not going to tell you ........

I'm off to bed ! :D

Jiberjaber · August 11, 2005

Now work on the ignition sense as well, so the car kit powers on when you turn on the ignition... or have you dared that one already?
D.

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Search and ye shall find :P

http://www.lexusownersclub.co.uk/forum/ind...=radio++pinouts

I have lost count of the number of times I have posted this and it has been ignored now!

squarehead · August 11, 2005

:winky: Jiberjaber - you are absolutely correct, I did also use your pinout layout to locate pin 4 - so my apologies and a big thankyou to you as I was convinced I was using the right pinout as pin 5 was empty - so cheers mate

I'm not going to bother with the ignition sensor as sometimes I use the carkit before I start the engine - thanks anyway!

What about using the car speaker - do I need a relay for that? Yes I know search is my friend :mat: but has anybody succesfully achieved it?

Ta!

Jiberjaber · August 11, 2005

:winky: Jiberjaber - you are absolutely correct, I did also use your pinout layout to locate pin 4 - so my apologies and a big thankyou to you as I was convinced I was using the right pinout as pin 5 was empty - so cheers mate
I'm not going to bother with the ignition sensor as sometimes I use the carkit before I start the engine - thanks anyway!

What about using the car speaker - do I need a relay for that? Yes I know search is my friend :mat: but has anybody succesfully achieved it?

Ta!

←

The Sat Nav uses a relay to switch in the audio IIRC, you could knock your own up using the mute to switch it (as well as switching the mute on the radio. I might do this on my next car.

I would definatly recommend using the ACC wire, as when your in a call, it will still stay connected till you end the call (Nokia CK7-W). I wouldn't be comfortable relying on the timer to kill the juice on the car kit.

The relay for the speaker would be real easy to implement.

Just a simple double pole, double throw (DPDT) 12V relay or triple pole (TPDT - if you can find one).

Then add a reversed diode across the coil, connect the mute upto one side of the coil and the +V const to the other side. This will trigger the relay ON when the mute goes LOW.

Cut the speaker wire, wire the speaker to the common of the relay conntacts.

Wire the car kit speaker output to the normaly OPEN contacts of the relay

Wire the car radio speaker output to the normaly CLOSED contacts of the relay

Then when the mute is OFF, the relay is not energised, so the audio is passed from the radio to the speaker.

When the mute is ON, the relay becomes energised, so the audio from the radio is cut to the speaker and the car kit audio is switched to the speaker.

If you can find a TPDT relay, then I would suggest adding a ground to the third common, and then connecting the normaly open contact to teh mute of the radio.

This is of course untried, might do it in the new car and post the details, I would strongly recommend you check the coil current and characteristics of the mute line before trying it though as you might find the car kit hasn't the capacity to drive the relay, which may then require a small driver transistor.... que issues with phone signal triggering chatter on teh relay via the driver

If I get round to it, I might knock a few up... :)

*EDIT* Just checked the Nokia instructions for the CK7-W and it states that it will drive a relay, but not what actual current it can sink!.... I would guess it is good for 100mA though, so that would be enough to sink two 12V, 5A DPDT relays (to make a TPDT relay ;) )

Less than a tenner (or a fiver depending on what your after) including a little box to make.