Sony Stalk (ADC) Voltage

I'm about to reinstall my riocar in my truck with a tuner module and wanted to check a few things first. 1) Does anyone know if the voltage in the line between the Sony wired remote and the tuner interface is 12 volts (I guess this would be the "ADC input"). 2) Is the 22K resistor actually in the tip of the Sony remote or built into the tuner interface (I can't tell from the Developer Information Page).

As far as I am aware the voltage used by the Tuner module for its ADC conversion is 5 volts [certainly the Chip (PIC Micro) they are using for the ADC conversion in the module runs on no more than 5 volts].

The 22K ohm resistor referred to in the Developer Info Page is inside the Tuner module itself between the socket where the Sony Remote plugs in, and the PIC chip which does the ADC conversion.

Thanks number6, after reading your reply and then rereading the Developer Info the answers pretty obvious. So I guess I'll have to drop the voltage from my steering will remote down to 5v before thinking about interfacing it.

What voltage? The only thing your wired remote of any kind should connect to the tuner module are pasive resistors without suplying any power. Those resistors and that 22kOhm thing make up a voltage divider (for internal 5V supply), and ADC measures voltage between them (0-5V).

So, either I missunderstood your post, or you missunderstood the wired remote description on riocar.org

Aha, you could provide ADC with 0-5V voltage directly, but I guess you would have to dissect your tuner then and disconect that pull-up 22k internal resistor.

Thanks for the clarification Bonzi. I was under the assumption that the Sonystalk had a 12v power hookup which passed through the resistors to the tuner (or Sony headunit). This is how mt steering wheel remote works: 12 volt signal from ignition passes through various resistors (depending on what button on the steering wheel is pushed) and a resistance is then read by the stock headunit.

Aha, so that just means you connect both ends to that 3.5mm connector which goes to tuner (and perhaps delegate some button to mean 'shift', if that makes sense in your particular layout).

Also note that currently tuner reports measured resistance whatever it is, but accepted values in player software are fixed (untill Mark attacks the stalk(s) as a part of traslation function of his Hijack kernel). So, at the moment, the only way to emulate Sony's stalk directly is by changing actual resistors. However, I would bet that within, say, two weeks we will have something more elegant from Mr. Lord's workshop :-)

Ahhh....that's how I hook it up. Now I just have to find where the ignition wire is connected. Thanks Bonzi.

Bob