BLE CAN Gateway

Overview

I’ve got a 2015 Passat TDI. I want to play with the CAN Buses. There are three CAN buses in the vehicle. a 500kbps drivetrain bus and 125kbps infotainment and convenience buses. I’m not sure yet whether the two slower buses are combined or separate, so I’ve got three CAN interfaces on this design.

BLE isn’t fast enough to transmit all messages but we aren’t likely interested in transmitting everything from the drivetrain. CAN filtering and some brains on the gateway itself will go a long way in managing the data load.

The goal is to disconnect the radio and MFI from the bus and put this device inbetween so that I can selectively pass data through. I didn’t realize that the MFI in particular was so “dumb” – the auto-polar people sit between the MFI and the rest of the bus and can display arbitrary data. I want to do the same.

v0 Ideas

  • sniff the diagnostic bus (OBD connector) - this is just the drivetrain CAN bus from what I understand but I’d be curious just to datalog when I take it in to VW
  • gateway the buses (two CAN interfaces per CAN bus so I can choose which CAN messages I want to relay (to disable specific CAN messages, change them or override them with my own)
  • DPST relay to connect both sides of the gateway so I can get out of the way and let the buses communicate normally
  • nRF51822 for standard BLE comms, could easily replace the soft device with their shockburst soft device to get 2Mbps if needed
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