it seems that you have to purchase the spec to get access to the protocol
74 Swiss Francs...
But, in my experience, ISO likes to break the information necessary to perform a task into a few specifications. There's a chance that you'll need other documents.
If such a library was developed could it be done open source
I can't imagine why not but you'd certainly want to talk to a lawyer!
A shield might need to be developed as well to allow for connecting to to the OBD plug
Probably not. Years ago my coworker bought a device that would connect to ODB on one side to RS-232 on the other side for about $250. I expect such things are still available and are now considerably less expensive.
What do you guys think of this?
It brings back unhappy memories of ISO. It cost me $200 for a 42 page document to get access to the three pages I actually needed.
There have been a few folks on the forum who could probably use an ODBdiunotm.
Did you have something specific in mind?