Using modern car stereo head units in a different car or on the bench.

So Another little project I started (never finished) was trying to control a modern CAN bus enabled Car stereo head unit.

I played with a Vauxhall unit ages ago this got me playing with the CAN bus and creating a WiFi CAN bridge so that I could hook the head unit on the bench to my car wirelessly.

That worked quite well, it would respond to my turning the key in the car and also display the station details on the display on the dash, but I never actually found a use for doing such a thing !!

Actually I was tempted to capture the steering wheel messages for the various controls and perhaps use them to turn my easy-tronic gearbox into something with steering wheel control. Poor man paddle shifter I guess.!!

Never bothered doing that either, short attention span and all that....

Anyway,, Recently I was given a faulty RNS-510 unit from a VW. Nice unit, big display, SATNAV, DVD, MP3 with 20GB harddrive.

Easy enough to get working on the bench but it still required some CAN messages to control things like the panel lighting, Ignition sense and other bits that used to be based on hard wires in the old days. Ignition sense was important as the radio, without seeing such messages would auto power down after a period of time.

So I broke out the WiFi CAN bridge again, found a friend with a VW and was able to capture the packets needed to talk to the radio on the bench. Near full control as well as the steering wheel control messages for remote volume and other functions.

Bit miffed as it turned out the GPS is not getting a lock so the SATNAV part is not fully working but it may need to be attached to the car and driven for that to work, who knows, I still have hope for it before I sell it for parts.

So this was just another random thought I figured worth sharing.

If you find yourself in possession of a head unit and wanted to fit it into a car or boat, either without the required CAN bus or perhaps a different make/model, it is not too hard to simulate the required messages with a few bucks and an Arduino at hand.

Have you, or do you intend to publish more on this work? I have a radio that only responds to the headlights CAN message (headlights on = the radio console dims) , I had hoped it would be a full VW CAN bus plug’n’go solution, but it was not. Though plug and wiring compatible 100%, it was very bad choice, as it it must have kept parts of the car “alive” because I came back from a 4 week break only to find it had flattened my battery. I can use the radio on manual and don’t mind that, ie not rely on CAN bus at all, but flattening batteries is out of the question.

You give me hope I may be able to build my own translator. Can you give me some links to articles you have written elsewhere, or to ones that have helped you do what you have achieved.

Many thanks, Rob