Transmit Stamp Data down 12 volt line

Chas

Isthere any info about on using stamp to transmit data down a 12 volt line (eg model railway track) to a stamp decoder at the end.

Just looking for info re the transmission of data, and setup codes.· Encoder and decoder I am ok .

Thanks

Charlie

GICU812

Do you mean on top of a 12v signal, or just using 12v?

If you needed there to be 12v running on the line, and send data on top of that, im not sure, other than maybe running a 13v signal on top of that, assuming it really was a train or something that wouldnt care about a little extra power.

If you just need to send data at 12v, just use a simple PNP transistor, hook 12v and wire to emittor and collector, and send a negative pulse to the base.

Chas

I want to have stamp based/pic onboard say a carriage and be able to send a signal (from a transmitter PIC connected to track)to the carriage via the tracks to turn light on or off. Each carriage would have its own address.

Thks

Charlie

Chas

Note that track voltage would be variable from o volts to 12 volts and polarity would change also.



Charlie

kevinb2050

I came across a system marketed for model trains called DDC ? or DCC a few years back that allows computer control of trains thru the rails via a digital signal while the rails had 12vdc on them (from memory the 12v power was not reversed for the engine as the code chip did it's own reversing and speed control ) each engine was fitted with it's own code module that recieved a signal to start stop etc. it may have been Atlas Model Railways- try a google search - hope this helps

MSDTech

If this is for a model railroad, you might want to look at:
http://www.nmra.org/standards/sandrp/consist.html
These are the standards that the model railroad industry uses for the manufacture of model railroad components, including DC and DCC. They might give you some ideas on how to transmit the signal. Also, if you make sure your system is compatable with these systmes then you don't need to worry about your system suddenly ceasing to work if you introduce a new component to the railroad.

Tracy Allen

One way to do that sort of thing is to introduce a high frequency signal onto the power line. Think something like telephone touch tones (which the Stamp can generate). On the receiving end a tone decoder like the LMC567 is coupled by a capacitor to the power line and it looks for the presence or absence of the specific tone.

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Tracy Allen
www.emesystems.com

allanlane5

"DCC" is the standard digital control system used on trains. It's a system of putting pulses on the track, which allows the decoder on each engine to get an operating voltage, as well as signal each decoder how fast you want the engine to go. The end result is many engines on the same track, each going their own commanded speed. It's really pretty slick.

However, it DOES require a centralized unit to generate the pulsing AC signal, and it does so with a few amps behind it. Any 'competing' signal could be swamped, or could result in DCC equipped engines NOT getting their signals.

Now, the "normal" system is DC controlled (which sounds like what you're talking about). This system is quite electrically "noisy", but you COULD capacitively couple signals onto the track (as described by Tracy above).

The usual BS2 based systems I've seen documented, solve this problem by running their own signal wire around the layout under the table. This gets you past the "variable DC" and "noisy signal" problems.