Can bus - does anyone know anything?

[rj]

Probably a long shot, but I would like to find some small Can Bus high power "high side" switches to operate headlamps, indicators, rear lamps and fuel pump. What I'm after is a small "local" device to enable me just to have  +ve, -ve and can hi / can lo to each lamp - I will, of course, also need something to send the can commands to them.

Does it exist or would anyone know anything about for example Arduino devices that could be used?

In "real" racecars there's a single common PDU, but I'd like those to be spread around the car instead to simplify wiring.

[tbird]

would this be any use, although it would have redundant relays, and no idea of cost https://www.blinkmarine.com/keybox/

[rj]

Unfortunately not. This also is one central unit. There's a few of those on the market; what I want is de-central units in each lamp / light as this would make it possible to run only one "rigid" wire to each (especially headlamp).

I know this is weight managing taken to the extreme, but that's who I am. (Sorry).

[tbird]

I wondered if they were small enough/cheap enough to live with the redundancy of relays and just use one complete keybox per load,  just to explain my thinking :-) 

[rj]

Ahh. At 14 x 13 x 3 cm they are probably a bit heavier than 3 meters of 1.5mm cable :-p

[tbird]

ooops, sorry yes that is quite chunky  , didn't look at size, only they looked small in the picture :-) 

[rj]

And don't get me wrong. I appreciate the effort.

I am thinking of something with a microprocessor and maybe four "highside switches" on a small board. TI make a 10A switch, and some make a programmable switch meaning that it can act as current protection at the same time. Ideally the microprocessor is programmable so that you can tell each unit what to react on: There's no need to be able to turn on each headlamp individually, nor front/rear indicator, but it would be nice that not all four indcators went on at the same time :-p

[tbird]

Have been trying to think if, as you are just looking for a switching protocol, you could use DMX instead of CAN bus , but can't think of any small relays that would do what you wan,t , and of course you already have the CAN bus fitted  , this was the sort of thing I was thinking off 

[rj]

It has to be can bus to be able to communicate with other automotive devices.

I know there's a development board here:

https://www.microchip.com/DevelopmentTools/ProductDetails/mcp2515dm-bm

and it may well end up with something I have to design myself although it would have been easier if someone here could point me to something I hadn't been able to find myself.

There is a decent central unit available here:

https://www.ecumaster.com/products/pmu/

and whilst it does not offer the de-central units I'm sure it could reduce complexity of the wiring loom.

 

[Strangely]

rj, if you do go homebrew, then teensy is about as small (and light!) as an Arduino nano, but has CAN bus built in. Apparently -- I have no practical experience with it, but was eyeing it up for my own project a while ago.

[rj]

Strangely,

You've just made my day.

Thank you!

[OliverSedlacek]

I'm part of the way there, having built a little PCB with four solid state high side 10A switches. It's dumb at the moment, but a lot smaller than four relays and fuses. As for multiplex comms, CAN is a bit of a challenge for maker/hobby stuff, so I'm looking at LIN instead. I'm happy to share more if people are interested.

[rj]

Always

[rj]

PS: I think the mirror in my Passat runs LIN bus - it often fails and will "black out" anything.