Data over 12 volt dc

Hobby electronics.

As a model railroad I want to send data from a PIC over the 0-12vdc
tracks to another on board mounted PIC decoder to drive some leds on
and off.

My request is re the data transmission, can that be done over a CAN
receiver ? Is anyone able to advise b est source for locating
suitable information. eg a hobby electronics group who specialise in
interface etc .

Your comments would be appreicated.

Regards

Charlie

 

[Tim Wescott]

swchuck@gmail.com wrote:

Hobby electronics.

As a model railroad I want to send data from a PIC over the 0-12vdc
tracks to another on board mounted PIC decoder to drive some leds on
and off.

My request is re the data transmission, can that be done over a CAN
receiver ? Is anyone able to advise b est source for locating
suitable information. eg a hobby electronics group who specialise in
interface etc .

Your comments would be appreicated.

Regards

Charlie

There's already an accepted standard for sending remote-control info
over model railroad track power, and AFAIK there's oodles of data on it
out there.

Why not use that?

An ISO 11989-2 CAN interface chip will _not_ be suitable for your needs
-- the last thing it's going to expect is 12VDC across it's petite
little pins. It won't work, and it may notify you of this fact with
sound and smoke.

You could use the CAN bus link layer and above, but you'd have to roll
your own physical layer that would be compatible with what you have --
probably by injecting an audio-frequency or slightly higher tone to
indicate a '0', and keeping your data rate slow enough to work with the
tone. You'd have to really understand how CAN works to make this a
success, however. If you have to ask, you probably can't do it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[David L. Jones]

On Sep 8, 5:55 am, swch...@gmail.com wrote:

Hobby electronics.

As a model railroad I want to send data from a PIC over the 0-12vdc
tracks to another on board mounted PIC decoder to drive some leds on
and off.

Probably easier to use wireless these days!
PIC -> RF Transmitter -> RF Receiver -> PIC

Have you looked at converting your layout to DCC control?
That way you can add stuff like that directly to your system.

My request is re the data transmission, can that be done over a CAN
receiver ?

No, CAN is not really suitable in this application.

Dave.

 

[Jasen Betts]

On 2008-09-07, swchuck@gmail.com <swchuck@gmail.com> wrote:

Hobby electronics.

As a model railroad I want to send data from a PIC over the 0-12vdc
tracks to another on board mounted PIC decoder to drive some leds on
and off.

going from a sationary controller to a vehicle mounted receiver
with the electircal connection provided by the power circuit?

My request is re the data transmission, can that be done over a CAN
receiver ?

probably not.

you're likely to find that the signal is rather noisy by the time it
reaches the loco, especially while the loco is moving...
perhaps you could encode the light control data in the frequency or
phase of the PWM on the tracks?

short range wireless is likely to be much easier.

Bye.
Jasen

 

[Tim Wescott]

David L. Jones wrote:

On Sep 8, 5:55 am, swch...@gmail.com wrote:
Hobby electronics.

As a model railroad I want to send data from a PIC over the 0-12vdc
tracks to another on board mounted PIC decoder to drive some leds on
and off.

-- snip --

Have you looked at converting your layout to DCC control?
That way you can add stuff like that directly to your system.

-- snip --

That's the abbreviation I was looking for when I so vaguely mentioned it
in my other post -- DCC control.

It's known to work somewhere between pretty good and really good.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html