Well....hmmm....I found out quite a bit. The only problem is, is that I have been convinced to not proceed with the installation of the smoke unit to DCC. :cry: I had a gentleman from the Digitrax user group help me with what I needed to know and do to get it installed. It definitely takes a lot more work than I thought. You can go to his web site to find the schematics of the installation. It is at the bottom of the page.
http://www.tcc.on.ca/~bobyoung/decoder installs.htm
The following is and explanation from the gentleman on how it is all supposed to work. I suggest that you look at the schematics on his web page before reading this, it will make more sense.
"You need to use a relay to flow track power through the smoke
generator, controlling it via a function output. To the best of my knowledge a
smoke unit will draw far more current than can be sourced by any decoder,
regardless of scale. A given function circuit (white, yellow, green or
violet) of a decoder (HO scale in particular) can only sustain current
from 100ma to 150ma. A smoke unit will demand current of 500ma to 1500ma. The end result is obvious, the decoder function circuit is destroyed.
The purpose of the relay is to act as a high current switch that can be
controlled by the decoder. The decoder function current can safely
sustain the current required to operate the relay coil/armature, the relay
contacts switch the smoke unit 'On/Off'.
The relay will be activated by the decoder 'function', similar to a light.
The relay requires a single 'normally open' contact. You should be looking
for a 'reed relay' or a 'PCB relay'. Therefore you should be looking for a
relay that has a coil/armature rating of 5vdc to 10vdc at 20ma to 50ma.
You will also require a series current limiting resistor, the size of which will
depend upon the relay coil/armature rating. Assuming a 50ma current for the relay coil/armature you would require a 120ohm, 1/8w resistor series resistor.
The cab switch is an option that is not really necessary. The cab switch
allows the user to run the locomotive without fear of the smoke generator being turned 'On' inadvertently.
The bridge rectifier is used to rectify the DCC track voltage into uni-polar
DC. The voltage regulator was used for this specific installation as it was
'S' scale. The user was using 'HO' scale DCC voltage which turns out to be
about 14vdc. The regulator ensures a constant 12vdc source voltage for the
'smoke generator'.
I figured that I would hold off on the installation of this until I was more comfortable with DCC. Also, I have been told that the after affects of the smoke 'oil' is not something that anyone wants to deal with. I haven't personally had problems with the oils, but apparently it is a big issue. Also the fact that it doesn't look realistic was brought up, but I could care less about that because I think it plain out just looks cool. I hope this has helped, and am sorry if it as deturred you from wanting to wire your smoke unit for DCC. If you do get it wired please let me know, I am still quite interested in doing it and if by some chance I do continue on with it, I will let you know of my progress.
Thanks, Freelancer
