Thread: Renault "Tuner List" Head Unit/CD changer hacking - Controls

Originally Posted by CristianC

Is possible that some models to use analog input (not SP/DIF) for CDC audio line? ( I hope)

look here:

http://www.planeterenault.com/forum/...&view=previous

peppe

Originally Posted by Vicne

Very interesting.
Pippolippi, is your model referenced as compatible ?

Mine is exactly like yours: RENRDW131-10 (Scenic II, November 2003)

I've found this page here where they sell CDC units, according to this info all HU Tuner List and Update List from 2000 on are compatible.

Originally Posted by pippolippi

Mine is exactly like yours: RENRDW131-10 (Scenic II, November 2003)

Then it's absolutely logical that you don't see anything coming out of the HU.
I'd say start the HU, then try to send only "PLAYING" commands every second, with track=1 and both times at 00:00:01 and see if you get acknowledges in return.

Originally Posted by Putput

I've found this page here where they sell CDC units, according to this info all HU Tuner List and Update List from 2000 on are compatible.

The "from 2000 on" means "digital sound link".

Originally Posted by CristianC

Is possible that some models to use analog input (not SP/DIF) for CDC audio line? ( I hope)

As far as I know, models before 2000 had analog sound between CDC and HU.
Which car model and year do you own ?

Originally Posted by Vicne

Then it's absolutely logical that you don't see anything coming out of the HU.
I'd say start the HU, then try to send only "PLAYING" commands every second, with track=1 and both times at 00:00:01 and see if you get acknowledges in return.

I already tried that with no success. As I said, I think that the level of my usb serial adapter isn't enough for the HU, so I'll have to wait until someone design a good interface circuit, that is rs232 compliant on one side and gives 0-12V on the other.

Originally Posted by pippolippi

I already tried that with no success. As I said, I think that the level of my usb serial adapter isn't enough for the HU, so I'll have to wait until someone design a good interface circuit, that is rs232 compliant on one side and gives 0-12V on the other.

I think that Ale's proposal in post # 131 should be OK. You don't need the stuff at the bottom to drive a relay (except the IC-powering part, of course), so it's rather straightforward. The IC should support 20V supply (absolute max) so maybe the Zener diode also isn't absolutely needed.
Of course, you need to invest in a 4050 but well...
If you don't want to go that way, you can increase the output voltage with a transistor, but if you invert the voltage, don't forget to do it twice...
To avoid damaging the HU with a short-circuit (as these proposals use the HU's 12V as power supply), maybe it would be wiser to use first a secondary power supply : a 9V battery should do the trick and you can test your circuit beforehand by setting your input on either 0V or 9V and measuring the output with a simple multimeter. Just don't forget to link your battery's negative contact to the HU connector's ground.

Originally Posted by Vicne

I think that Ale's proposal in post # 131 should be OK.

I'm not too sure: looking at the characteristics for the hef family, the minimum input voltage is -0.5V, the max low input (at 15v) is 4V (probably 3.5 at 12v) and the minimum high input is 11V (probably 9V at 12v).
With this characteristics I think it makes no difference connecting the HU to the serial port directly or through the buffer: if the level coming from the HU is critical to interface directly to a serial port I think it'll also be critical wrt the hef4050b input. OTOH the levels coming from a "real" serial port (+12,-12) are outside the lower limit (-0.5v) and a laptop/usb probably won't have enough voltage to drive it high. If you put a divider network things are even worse.
Maybe the best solution is to use a max232 and the buffer.

Originally Posted by pippolippi

I'm not too sure: looking at the characteristics for the hef family, the minimum input voltage is -0.5V, the max low input (at 15v) is 4V (probably 3.5 at 12v) and the minimum high input is 11V (probably 9V at 12v).
With this characteristics I think it makes no difference connecting the HU to the serial port directly or through the buffer: if the level coming from the HU is critical to interface directly to a serial port I think it'll also be critical wrt the hef4050b input. OTOH the levels coming from a "real" serial port (+12,-12) are outside the lower limit (-0.5v)

I think a simple diode could take care of that...

and a laptop/usb probably won't have enough voltage to drive it high.
Maybe the best solution is to use a max232 and the buffer.

Well, to keep simple, the solution of the comparator (LM234) proposed my Mox would probably be better suited. Power it with 12V, enter your serial port Tx with a diode on a positive input and the set the threshold of the negative one with a divider bridge. (e.g. 47K/10K to get a threshold around 2V - but the diode causes an offset). You could even put a 100K potentiometer to be able to adjust the threshold.

Any comment is welcome.