A bit more forward progress. I got the CAN bus shield working, and though the libraries sample code are a bit lacking, I was able to do the basic "detect RPMs, accelerator pedal position, etc." thing over the OBD-II CAN bus connection. I'm probably going to have to do some proper library routines to make things manageable as I add more stuff, but it all seems doable.

I also received and installed the Lockpick last night. I'm hoping that it responds to CAN commands so I can make the task of switching inputs easier -- right now the only way to switch to its AUX A/V input (where the empeg display and sound will be going) is to hit the "Back" steering wheel button 4 times, then select the input from a menu. There's enough lag that this would be a real hassle. I was also hoping to be able to rig things so it switches away from the empeg input when calls come in, and without a dedicated CAN message I can send to the Lockpick, that's going to be difficult or impossible. If I can't find any dedicated commands, I'll have to settle for sending steering wheel presses. The Lockpick itself does some CAN mangling, so I'm thinking about monitoring the messages going into and out of it to see what it's doing for some ideas.

I have a Raspberry Pi arriving tomorrow, so I'll probably start playing around with that next. I'll need to check in with John to see if his code for writing to the RPi frame buffer is in good shape. Once I know how the RPi is going to fit in, the actual empeg install is next -- there's not enough room in my glove box for a sled, so I'm going to have to go the sledless route with Hijack's force car mode and/or force DC functions. For the time being, this rules out using the empeg as a head unit, but I think there are too many missing pieces for that now, anyway. Maybe some day.