my home made OEM radio -> ipod controller.

[Thaniel]

Just a quick update

Sounds like you've made progress. I find the bluetooth interesting. If you have a blog or post feel free to link to it. It would be an interesting read.

I keep trying to get my son to put together an arduino driven MP3 player that runs just off a Flash card. Then I could ditch the ipod altogether. So far he's only researched it a bit and then seems to loose interest. I'm not holding my breath :-)

Thaniel

[swordz]

Hello again. So I got my E39 radio running at home. I had to replace the mid/iris, because mine was dead. I connected it to instrument cluster and the radio itself (an E39 version of CD43) just like before and had to add 10k resistor between iBus and 12V, because it would drop below 10V for some reason. So yeah, all is good in that department, but CD changer emulator still wont work. I tried both optocoupler and the simple 2 transistor versions of connection to no avail. The only difference being that optocoupler version brings iBus line to very low voltages, thus causing radio and it's screen to stop working. The 2 transistor version does not do that however. All is working with the emulator connected, but pressing corresponding "CD" button twice does not switch on the emulated CD changer. Do you know whether E46 and E39 communicate differently with the CD changer through the iBus? If so, a quick pointer would be nice.
P.S. I am now using an E39 radio without a screen which uses the mid/iris as a screen. This radio has the same insides as the CD43 in my friend's E36 does. It is codenamed BP9263 (with a screen) and BP9272/BP9273 (an E46 and E39 versions I believe).
Thanks.

[Thaniel]

Have you tried it in a car? That's really where it matters. I've used this on a 2001 E53 which is very similar to an E39. Don't think I changed a thing. Well the buttons on the E53/E39 radio are completely different. But my E53 came with a CD changer (that I removed). Perhaps you have to code the radio? But simply watch the bus messages and see what message comes across when you press the CD button. make adjustments to the program if necessary.

And used the optocoupler for interfacing to the can bus on 6 different E46's, My E53 and a few E39's to capture the A/C button status. Betting there is a problem in your simulation of the BMW Bus. My first thought is to change your resistor. 10K is too big. Measure a car. I think it is near 220 or 330 ohms. I forget which. But definitely not 10K.

Good luck

Thaniel

Hello again. So I got my E39 radio running at home. I had to replace the mid/iris, because mine was dead. I connected it to instrument cluster and the radio itself (an E39 version of CD43) just like before and had to add 10k resistor between iBus and 12V, because it would drop below 10V for some reason. So yeah, all is good in that department, but CD changer emulator still wont work. I tried both optocoupler and the simple 2 transistor versions of connection to no avail. The only difference being that optocoupler version brings iBus line to very low voltages, thus causing radio and it's screen to stop working. The 2 transistor version does not do that however. All is working with the emulator connected, but pressing corresponding "CD" button twice does not switch on the emulated CD changer. Do you know whether E46 and E39 communicate differently with the CD changer through the iBus? If so, a quick pointer would be nice.
P.S. I am now using an E39 radio without a screen which uses the mid/iris as a screen. This radio has the same insides as the CD43 in my friend's E36 does. It is codenamed BP9263 (with a screen) and BP9272/BP9273 (an E46 and E39 versions I believe).
Thanks.

[swordz]

I changed the resistor to 270 ohms and it's working the same, with a slighltly increased iBus voltage (a bit over 12V). I think the resistor doesn't matter much here, as long as iBus is kept at around 12V.

So I decided to try my board (with the radio and iris I mentioned before) in my cousin's e38. He also has a cd changer present, so it was a perfect opportunity to test it.
With his cd changer connected, my setup could easily switch between cd player and cd changer with a single press of a corresponding "cd" button. However, as soon as I disconnected the cd changer and connected my board I was no longer able to enter cd changer mode (cd button did nothing when in cd player mode, just like when testing at home). Oh and I didn't use a resistor when testing in car, because it read a nice 12.4V between GND and iBus.

So from that I believe I can draw a conclusion that the cd button for my radio produces a different message. I can see that message on my oscilloscope whenever I press the button, but don't really know how to translate that.

From the top of my mind I'd guess that I need to connect arduino to pc while connected to the iBus and look at the serial monitor if anything shows up. Which I guess needs some extra lines added to your code

[Thaniel]

yes you don't need a resistor in the car as it already has a ibus network :-)

So from that I believe I can draw a conclusion that the cd button for my radio produces a different message. I can see that message on my oscilloscope whenever I press the button, but don't really know how to translate that.

From the top of my mind I'd guess that I need to connect arduino to pc while connected to the iBus and look at the serial monitor if anything shows up. Which I guess needs some extra lines added to your code

Look at the program. Pretty sure we left some #define's in there that if set will output the ibus to the serial monitor. Very simple. Seems you are resistant to looking at the actual code?

Thaniel

[swordz]

I'm not resistant, I'm just unsure about what needs to be changed, but I guess I'll figure it out, since I have worked with serial monitor a bit on my other projects.

In the meantime thanks for the pointers, I'll keep you posted if anything good comes out of it.

[swordz]

Ok, so I've made some progress: now i can see Arduino Rx responding to iBus messages, but it doesn't go fully low as expected, it just drops to 4.5V when iBus goes low.
I'm not sure what is causing that, because when i promptly short Arduino Rx to GND, the Rx then goes low as expected. When I short Tx to GND, the iBus goes low accordingly.
I have checked my circuit a hundred times, so that is not the culprit. I will try it out today in my cousin's E38 to see if anything changes.

I also got some questions about your code:
1. Do I have to use HardwareSerial.cpp provided with your code? Because it doesn't compile.
2. After deleting HardwareSerial.cpp, changing #define Kbus Serial2 to #define Kbus Serial and setting Rx to 0, Tx to 1 (because i use Arduino Uno and Nano) your code compiles,
but in serial monitor it only prints out a letter "K" and a little box character, like something interrupts or corrupts the message.
I fiddled with the code a bit to fix this, and after moving Kbus.begin(9600, SERIAL_8E1); before Serial.begin(115200); it now prints out the version of your code. I wondered why is that?
3. The serial monitor doesn't print out anything more that the version of your code, but I guess that is because it never sees iBus communication, since Rx doesn't go low.

Any ideas what could be holding Arduino Rx high when it's supposed to go low?

[swordz]

Quick update: after adding a SN74HC04N inverter and another NPN transistor, the Rx is now pulled low when iBus does.
Guess it's down to coding to get the rest working.

[swordz]

Final update: I finally got it to work! Besides adding a SN74HC04N inverter and another NPN transistor, I removed all the lines that had to do with serial and it now works perfectly even at home!
So if anyone wants to know if this mod works with an E36 CD43 radio, then yes, it works! If anyone need any details, I'm happy to share.
All thanks goes to Thaniel, i probably would've never done this without your help, very well done, hats off to you.

[Thaniel]

Final update: I finally got it to work! Besides adding a SN74HC04N inverter and another NPN transistor, I removed all the lines that had to do with serial and it now works perfectly even at home!
So if anyone wants to know if this mod works with an E36 CD43 radio, then yes, it works! If anyone need any details, I'm happy to share.
All thanks goes to Thaniel, i probably would've never done this without your help, very well done, hats off to you.

Great to hear it is working. I logged in to try to help but looks like you've got it. Good deal.

[ba114]

5 year bump (sorry). Id really like to be able to make this, but i only need to make something that emulates the cd changer so i can wire in something to the cd changer audio inputs.
Is there something in your files that only does this without all the ipod stuff?

I assume the attached would be all i need? Additionally, can i run this on a spare pro micro i have lying around?

Ibus.jpg