we're trying to make an android application that reads from a vehicles OBD-II port, but also has the ability to start the car, lock/unlock doors, window control etc.
Sounds like a illegal action in most countries.
If I understand correctly you want to make the following pipeline:
Android BT <---> BT Arduino < --> ELM327 <--> ODB-II
You could just connect - http://www.sparkfun.com/products/9555
- with the Arduino using NewSoftSerial - http://arduiniana.org/libraries/newsoftserial/
- remember that TX connects to RX and you need a common ground. I would certainly not make a separate PCB for that.
You have to search the forum for bluetooth Android side, no experience with that one. Keep us informed of your progress.
Thanks for the reply man. As far being illegal, I'm thinking it's not because it basically does the same thing that the Buick and GM apps that you see commercials for. Either way though, it's not, and never will be, a commercial product, its only a school project. I totally agree with your comment that we normally wouldn't need a separate PCB; unfortunately though, our professor will not let us buy design boards and use them in the final version. He wants all the hardware on one chip and wants us to get experience designing and making PCBs, even if we just make them straight from the EAGLE files.