Is there any way to maintain steering wheel controls with a carPC? I'm guessing I would need something to interpret the CAN signals, and some way to pass those signals to the computer. Is there any relatively simple way to do this?
Give me a few weeks and I may have a solution for you. Once I get my trailer converter built i am going to start sniffing the CAN bus to make a Ipod adapter with text. (Not going to pay $200 for a box with a PIC micro controller in it)
Once I get the basics done (ie buttons in and text out to the display) should be easy to port to other things long as you know how to get command into and text data out of the mp3 player. Apple was nice enough to give us a serial port and I happen to have one so starting there
There's not much out there right now dbduke. I've looked to no avail. Basically we'll have to wait for some home grown stuff. I was thinking, and it would probably work, getting a Fusion Brain controller and then running that with the PAC box or the Connects2 box. Basically if you could convert the CAN signal to an analog or digital signal, then you could use the Fusion Brain. But if some one makes a CAN reader that interfaces with a serial port or a USB port, that would be ideal.
This is really surprising. It can't possibly be that hard to do. Do you know how can signals are encoded? If there was some way to get the code, all you would need to do would be to use some kind of simple DAQ interface to read the signal, and then writing the code to interpret it should be cake.
Are we aware of anyone that makes a USB<->CAN bridge? That would be pretty fun to screw with.
wireb, you have a thread for any of your investigations?
Also, I have a dealer installed ipod adapter. It integrates with both the MFD and the MFSW controls. It is 100% pure crap though. I would happily dig into the dash, get into it, and try to determine what ICs they are using and possibly reverse engineer, if needed.
No thread yet I just dug up some free samples I had at work last week after I bought my car. So I need a little time to get going . Can directly to USB I would not recommend. CAN <-> Serial <-> Cheap serial to USB adapter is the better route. Microchip makes many controllers with USB in them but you have to write the OS driver your self. (pain in the ass + you have to support multiple OSes) Where the cheap (few bucks on ebay) USB to serial adapters all come with drivers already for almost all OSes. (I use them all over the place at work and work fine under AIX (with some work), linux, XP, Vista (no apple so far to try them on)
Once I get going should I hijack this thread or just start a new one?
Sorry dbduke for the hijack (just let me know if you want me to move this)
Probed the entertainment can bus and it was a lot busier than I expected. Looks to be running at 50kHz clock speed that should not be too hard to snoop.
Here is a timing pic of the bus.
Putting a order into digikey for some P-Fets for my trailer adapter anyway so will pick up a few mcp2551 and MCP2515 (Can transceiver and controller SPI connected). Need to digest the MCP2515 data sheet some more to see if a 20MHz system clock can run a 50kHz bus (may be too fast). But it DOES have a "Listen" mode for snooping built in. If I get the timing right it should not take much on my part to get that to dump out a serial port.