DCC hard wired

[lizzardlife]

Just hard wired a 2-8-0 consolidation with DCC/sound.  Also replaced the headlight with 3mm LED.  Everything working well but what to do with smoke?  This train has smoke and I would love to be able to turn it on and off.  Any suggestions on which dcc controller I should use next time so I can control smoke?  Considering installing a micro switch under the tender. 

[Jim Banner]

First, you will need a decoder that has a spare function output.  If your 2-8-0 has no tender light, you already have that but will have to remap it to another function button or you will get smoke only in reverse.

Combination sound/motion decoders generally have little extra current capacity.  After measuring motor stall current, headlight/tender light current, and smoke unit current, you might be able to run the smoke unit directly off the decoder.  But more likely, you will have to use a transistor switch.  This takes a very small current from the decoder and can switch a much higher current.

A second approach would be to add a second decoder just for the smoke unit.  You can either run this on another address or on the same address as the sound/motion decoder.  In the latter case, you will have to remap some addresses.

Your idea of a switch under the tender is another possibility although I would tend to think of putting it on the back of the tender.  It would be a trade off between easy access and being noticeable when the locomotive was running light.  There are some very small slide switches available.  I have a Hudson with a smoke unit controlled by a tiny slide switch just above the cow catcher.  Even when you know where it is it is still hard to find, it blends in that well.  An advantage of a switch at the front of the locomotive is one less wire between it and the tender.  (The extra decoder approach has the same advantage if you install it in the locomotive.)

Jim

[renniks]

Decoder functions usually have an individual current capacity way below that needed to 'run' a smoke unit.
However have recently seen an advert. for a decoder with a special function o/p specifically for a smoke unit (Digitrax?)but don't think that it is a Sound job.

Eric UK

[hminky]

How about a magnetic reed switch?

http://www.horizonhobby.com/Products/Default.aspx?ProdId=MNT3205805&utm_source=froogle

Harold

[Bill Baker]

Harold,
What in the world is a reed switch?  I looked at the Horizon website you posted and I still don't know what they are or how they are used.

Bill

[hminky]

Harold

[lizzardlife]

Thanks for all the ideas, I think for now the slide switch on the loco is a great idea. 

[Jim Banner]

Some of the newer smoke generators draw less than 100 mA, which many decoders can handle.  But many (most?) decoders are rated by total current, motor plus lights and other functions, so even 100 mA can be quite significant.  A transistor switch can draw less than 1 mA from the decoder while switching about any current you can name.

Jim