uwg

Does anyone know how to hook in to the driver information system in the dash? Since Audi's NAV system can use the entire "screen" for its menu, there HAS TO BE a way to hook up to it.

I'm considering replacing my factory CD changer with an MP3 player (carplayer.com), using the DIS to display current artist and song. Maybe I could get the Nav cluster (center console) and modify it to control the carplayer.

Any ideas on this would be greatly appreciated. And if this works, I'll be sure to make the schematics available to everybody.

DebauchedSloth

The CAN (Car Area Network) is a fairly open spec - you can even buy microcontrollers with CAN interfaces. Evaluation boards are fairly cheap,
but you'd have to do the programming yourself. The boards include just about everything you need to interface to the CAN, too.

I'm fairly tempted to try this myself, though it might be an involved task since you'd have to reverse engineer the CAN messages (probably pretty straightforward...but you never know.)

Two things worry me: the first is the possibility of blowing the CAN when you tap into it. I'm a software guy If the HW can go bad, it will do so for me. The second is not knowing exactly WHAT is on the CAN. I mean, if it's just informational stuff, fine, but if things like throttle control are on this bus, well, let's just say that things could get interesting during the debug cycle of the process...

//Greg

uwg

Greg,

thanks for the pointer. I found a host of information on CAN. Hardware interface chips from Motorola are in the <$5 ballpark in small quantities Also, the Motorola location that develops these "Controller Area Network" solutions is not even five miles from my house!

I did find out that there are fast and slow CAN protocols, and the fast protocol is used for "powertrain electronics" the slower speed for "body electronics" -- I'm assuming that the latter includes most accessories, the DIS and the audio system.

I got in touch with a friend of mine at Motorola and he's going to find the people who do CAN stuff out there.

If I get an interface chip or a development kit, does anybody know WHERE to hook up to the Audi CAN inside my vehicle? I'm not one for tearing down the dash, so any non-intrusive way would be greatly appreciated.

Thanks in Advance!!

Bollinger

The physical layer for CAN is not specified in the spec. So, for example, it could be optical (it's not), it could be +5,-5 differential signalling. It could be -8,+8 RS-232 common-mode signalling. It could be 0,+5 "TTL" signalling. And of course, the speed can vary.

You need to know which it is before you hook to it.

I believe the CAN network is the same as the VAG 1552 interface somehow. Nearly everything on the car is bussed onto that network, that must be the CAN one.

Once you can talk to the bus, you need to know what to say. Good luck.

If you do figure out how to get onto the network, I want to know how to send the signal that makes the message "depress brake pedal before moving shifter from park" away. I don't need the interlock turned off, just the message.

DebauchedSloth

The voltage can be readily determined and mapped into whatever the microcontroller wants.

As for reverse engineering the protocol, based on what I read, it looks fairly straightforward (if somewhat scary) to do.

I bet you're right; the VAG1552 probably does interface to the CAN. Further, this implies the low-speed CAN since the various 1552 emulators are using PC serial ports. I doubt those serial ports are handling megabit port speeds...

//Greg

uwg

looks like VAG-COM *can* do this already -- so the CAN should be on the OBD plug. I found a whitepaper somewhere on this too -- imagine the possibilities. Maybe a remote starter as a plug-in solution -- intercept CAN-codes for unlocking and send them to the ignition key...

Harmless

The Passport SR-1 has a matrix display exactly like the information system. I was thinking it would be really cool to integrate the two, but I hadn't yet starting thinking if it was feasable.

I'd like to hear about your progress.

Audiablo

True, there are some amazing possibilities here. If the CAN knows when those useless bottom buttons on my steering wheel are pressed, they can be used to control the carplayer...

You can integrate a cheapo GPS, since they constantly spew out all their current data via their serial port...

Doug2.7

How about airbagging the passenger side??? I know a few mother-in-laws that ... oh well, just a tho

uwg

I'm all for toys. I can't wait to recode my locks to do remote windows -- not that I need that with Chicago Winter waiting outside, but still!

Don't have to worry about "deploying" a mother-in-law, but I hear rumors that Audis are babe-magnets. I'll keep you updated on the progress ;-)

I also have a feeling that the power sets, mirrors, and steering wheel are on the CAN bus. I'm just thinking minor mods for those now -- like adding "memory" to the passenger seat or a the passenger side mirror moving down (for curb view) when putting the car in reverse.

Or turning on the lights when I turn on the windshield wipers (law in Illinois)...

Or, or, or... but back to reality. Right now I have a potentially fully wired car on my hands. Need to figure out how to wire into it...

If time allows, I'll try to get in touch with Uwe from Ross Tech tomorrow and see what he has to say about the relationship between ODBII and CAN.