OBD-II became the mandatory I/O diagnostic port on cars starting around 1996 in the US. Considering that the interface consists of a couple of I/O lines, serial/usb adapters have been ridiculously expensive for quite a while – especially newer USB versions. [Renan] sent in this PIC18F2450 OBD-II interface. The designer says he can provide boards for just over $6 and programmed PICs if there’s interest. The chip is a few dollars, and everything else is pretty cheap too. Need to work on your car? This thing will cost $15 or so. I think I just might have to burn out a board on my mill later.