Hi all.

Well my projector is in a usable state (ok, let's not go as far to say finished), so now I'm looking to take on another project.

I'm planning on fitting out a camper van, something like this, but probably not as flash (a Toyota Hiace):
Click to view attachment

Whilst thinking about lighting and controlling the electronics I came up with an idea. Put everything on some kind of bus. That way, things like switches can be changed around or made to control more or less devices (eg a light switch by the bed could be a master switch for everything that is still running that shouldn't).

Right, that's the intro, now to my first question - what sort of bus to use?

It would be great to have the slave devices both compact and simple. Perfect would be if I could avoid using a micro controller at every one.

First idea was I2C but that seems to be short range, on same pcb kind of stuff. And it only has 8 ID's as far as i can tell.

So, other ideas I've had are CAN (used in new cars), RS485... I've got zero experience with those.

Anyone got experience with home automation stuff?

Sure, sounds like fun. Let's agree that everything in the vehicle is already on a "bus"?

No takers? Oh well, I'll start with what I have and go from there.

I have a solar panel, an inverter and a fridge (12v fridge). Planning on getting a deep cycle second battery for running all the accessories. Have built a voltage sensing switch to click in a charge the second battery. Above 13.8v it will join in battery #2, with allowance for 1v drop after join. Will see how that goes .

I picked up some 6x9 inch speakers and a 12v junction panel/fuse box at the weekend. Now I just need the van!

Yes, well when i mentioned bus lighting to a guy at work he thought I meant the other sort of bus.

If you are using an inverter for standard household lighting and appliances, you can use radio switches and simply program their codes for each use desired. Take it from Billy Mays!

http://www.thehandyswitch.com/

Seriously, a better variation:

http://www.adhocelectronics.com/Products/W...ighting-Control

No, I plan to run as much stuff directly from 12v as I can.

The fridge is 12v (it has a transformer in the back for 240v). Last night, I discovered the fridge draws over 5A!

I will use either 12v halogens or LEDs for lighting, water pump will be 12v. Inverter will be for powering incidentals/tv/projector

EDIT: Bought home the van last night. Then discovered a leak(s) in the garage - no time for playing in the van

I've decided to use 12F683 PIC micros. They're $6nz each here in small quantities but I might try and pick up a bulk order when I get the code organised (started )

I'll either use logic level serial (easily converted to RS232) or an RS485 (I believe this is just differential serial). I hope not to require too many extra components for each device.

Will see how it goes. So much to do.

Building/Programming/Spending... Can't figure out which one to do next...

Well, I got my own programmer working with the 12F683 last night (I got it working with a 16F876 at the weekend).

It's possibly the most complicated LED flasher ever (esp when you include the custom programmer, made from a 16F876)

So then I ordered 20 of them off ebay . I've got two to play with in the meantime, so I can really get started.

Meanwhile the building process has really got started...
Click to view attachment

I picked up some batteries - 2x6v @220Ah :~) The charging system is now using a 12F683 itself to decide when to join the aux battery into the vehicle battery, when it passes 13.8v (ie it is charging).

I'm writing bit-bashed 9600 bps serial at the moment. Transmit works (not hard, just uses delays) but receive is still not quite there. I can read it ok only if there are at least two bits between transitions.

Hmmm... I guess that means about 25 from 255 possibilities