|Hardware: Laser T-962A TVM802A FilmScanner ePump «Classic CAN»|
an automitive CAN Bus system for classic cars
This is the very early stage of the development of a CAN Bus system for simple automotive purposes.
In the olden days, cars had hundreds of meters of cable in them, connecting switches - like the light switch - to lamps and motors - like the headlights and taillights - of your car. As cars became more complex, this simple logic would no longer work. As electronics became cheaper and more common in cars, Bosch introduced the CAN bus system in 1986 which was first put into a BMW 8 Series car in 1988. CAN is now standard on mandatory OBD-II systems in all cars built after 1996 in the U.S.,, since 2001 in Germany.
After taking apart myVW Van from 1972 to convert into to an electric vehicle, it became quite apparent, that I would not be able to save the original wiring, and that it would make little sense to rewire the original setup. All of the combustion engine wiring was now obsolete anyway, and new wiring had to be introduced for battery management and speed control, plus many safety features that are required for an electric vehicle.
And while we were at it, why not add all the convenience features of a modern car: automatic vipers, automatic headlights, and hey, with radar systems available, why not add TACC and traffic sensitive high beams?
So the idea was born to convert the entire VW wiring from 1972 copper salad to 2016 CAN bus magic.
High level list:
Low level list:
Lots to decide. Hey, I said that this is an early stage ;-)
Size and Connectors
Let's assume that we want to replace the basic automotive relais. They have two connectors to the coil and two or three contacts to the switch. The CAN bus variant requires two additional connectors for the bus.
These Relais have a footprint of 28mm x 28mm and are 25mm high or taller.
I want to make the modules themselves modular, so I decided to create a PCB as a base plate that is 28mm wide and varies in length, based on requirements, yet aiming at the standars 28mm for basic relais setups. The base plate holds all connectors except CAN.
Soldered vertiaclly onto the base board is a CPU board and as many input and output bards as needed for that module. The CPU module also holds the power regulator (if possible). The CAN connectors are on the top end of the CPU board.
(c) 2012-15 Matthias Melcher