Quick Help - Connecting Smoke
Seuthe smoke generators are by far the most popular brand of smoke units available. Their #22 and #27 generators are commonly used in OO/HO models.
Connection to a Zimo decoder is very simple, as all current Zimo decoders provide enough power from a single function output to drive one. Typically, needing between 120mA and 180mA.
There are no additional components required - simply connect one wire of the Seuthe unit to the decoder's BLUE (common positive) and the other to one of the decoder's AUX function outputs. It is common practise to use the BROWN wire on Zimo decoders, but there's no reason in principle why any of the others couldn't be used instead e.g. GREEN, or a solder pad for one of the higher AUX/FA outputs where available.
You could even use the WHITE or YELLOW outputs, but you'd have to change additional CVs so that these became non-directional, as they are really intended for directional lighting!
Of course, whichever physical output you decide to use, there must be a Function Key defined that gives you control of it. YouChoos calls the GREEN output AUX3/FA1 and the BROWN output AUX4/FA2. If you are ordering a sound decoder, then it is worth checking that there is a Function Key defined to operate that output - we'll customise the project for you if you ask up-front of course!
It is easiest to control a smoke generator as a simple on/off feature, but it is also possible to make the amount of smoke produced dependent upon the speed or load on the motor. There are even safety features to automatically switch it off after a pre-defined period. See the Zimo decoder manuals for more information.
By way of more inspiration, below is a link to a customer video (thanks Steve B!) which shows the control of various custom-built smoke generators giving safety valve, draincocks and cylinder steam as well as synchronised chuffs from the chimney, all in O gauge locos. The installation, setup and configuration is obviously a lot more involved, but it goes to show just what is possible, so enjoy!