smoke unit and sound

[a10driver]

i want to put a smoke unit in a loco that has got a howes sound fitted.

can i wire the smoke unit direct to the motor or will i have to wire

it to sound module.

 

cheers a10

[Marty Mc]

Hi

 

You can wire it to one of the function outputs, it is worth picking up this months edition of the Hornby mag as it has full details on adding a smoke unit. When I add a smoke unit such as seuthe 22 or 27 which is rubber lined and suitable for DCC I always add a relay into the circuit so I reduce the chance of damaging or destroying my sound decoder.

 

The easiest method firstly is take the blue wire positive and join the green and purple together. Then solder the blue to one of the smoke unit terminals and the green/purple to the other. Remap the functions so you can switch on off.

 

The safe method using a relay.

 

What we want to do if their is a short in the smoke unit or if it fails is protect the decoder and we do this with a micro relay. It also allows you to add more than 1 smoke unit in parallel for the cost of 30mA approx on the decoder side. You generally get more smoke with a relay because voltage is direct from the tracks.

 

The following photos will help you.

 

Relay used is a DPDT micro relay 1 A max with a 30mA coil (control side of relay)

 

Feeds from track go to centre pins.

 

 

Here we have the red and black feeds which will go to the track or pick ups. The purple goes to the negative terminal on the control side of the relay. If you look closely I have cut out 2 terminals as they are not needed. The blue will go to the positive side of the relay beside the purple.

 

 

The last 2 wires you can see without heat shrink are the tails which will feed the smoke units.

 

 

 

This is it finished, Ignore the resistor on the blue that is outgoing and nothing to do with relay. I have installed 100's of relays into locos and never had a problem some will suggest adding diodes across the coil but??? I just cannot see the practical reason. II apply KISS. You can also look at building storage tanks, putting in low voltage by pass on the relay and adding syncro smoke but thats another separate issue.

 

 

The result

 

Mallard with duel smoke units lights and sound.

 

http://www.youtube.com/watch?v=J4UrdD9tHGo

 

9f with smoke and sound and lights.

 

http://www.youtube.com/watch?v=gBnCMpZJce4

 

Relays are a must in n gauge due to the high currents. This Graham farish A4 has DCC sound a relay and duel smoke units with a storage tank plus lights.

 

http://www.youtube.com/watch?v=FuATRsce0mo

 

Best of luck but worth getting the Hornby mag..

[Nigelcliffe]

some will suggest adding diodes across the coil but??? I just cannot see the practical reason

 

The practical reason for a diode is the EMF pulse created by the coil when it is turned off. The decoder goes to "off", and the magnetic field in the coil will generate a pulse backwards towards the decoder. The size of this pulse varies, depends on relay, but the voltage can be many times that of the input voltage; so the brief voltage spike may be of 50 to 100v (or more) coming from the relay.

 

Now, whether this actually causes any real world risk to the decoder is debatable, and practical experience suggests the risk is minimal. But, if going for a "safe" installation to "reduce the chance of damaging or destroying" a decoder, then a tiny cheap diode over the coils seems a trivial addition.

 

- Nigel

[Marty Mc]

Hi

 

Now, whether this actually causes any real world risk to the decoder is debatable, and practical experience suggests the risk is minimal.

 

Fair enough Nigel I do understand the theory and why, in reality I have installed over 200+ smoke and relay's without a diode and never a problem. I have installed diodes in the past across relays in an industrial applications and on the big old relay boards that you just cannot convince the customer to move to PLC's.

 

As Nigel said its cheap if you feel the need do so but in practical experience I just don't see the need to bother.

 

Cheers

 

Martin

[a10driver]

hi

 

do you have to use a relay it is on a oo loco

and the smoke unit onley drawes 140ma .what would would happen

if you wired it direct to the motor. we want to put the loco,s on the club layout.

it would involve a lot of work to put relay,s in them

 

cheers jack

[Nigelcliffe]

If the decoder output is rated appropriately, then its fine, put it on a function output.

Fitting a smoke unit to the motor output will make the decoder's job of controlling the motor much harder, and running quality will probably suffer.

 

If its a Howes decoder, then its a LokSound, probably either 3.5 or 4.0 depending on age. The official output ratings of those is 250mA per output. The Manuals for a LokSound (on the ESU website) say which sorts of smoke units are suitable, but would expect a 140mA unit is fine.

(NB, the Micro has lower output at 150mA per function wire, so marginal for a 140mA rated device).

 

 

Had you been using a Zimo, then using relays seems a somewhat puzzling solution as the Zimo decoder has specific outputs to increase/decrease the smoke generation based on how it is driven. Can even do a "make lots of smoke" function in conjunction with fans or other smoke control valves. You could achieve a basic version of this with an ESU, by using the "dimming" functionality on function outputs.

 

 

Personally, I'm not convinced about using smoke generators in motors; its throwing out a load of not very nice stuff which then lands on models, plus whatever it does to your lungs whilst its around in the air - though its not quite the same, if you visit the home of a smoker you find a sticky substance which gets everywhere.

 

 

- Nigel

[Lady_Ava_Hay]

Personally, I'm not convinced about using smoke generators in motors; its throwing out a load of not very nice stuff which then lands on models, plus whatever it does to your lungs whilst its around in the air - though its not quite the same, if you visit the home of a smoker you find a sticky substance which gets everywhere.

 

 

- Nigel

 

I'm with Nigel on this. That smoke you are seeing is actually half burnt oil. It is generally suggested that these sort of carbon based chemicals having been converted to something toxic by heat, are carcinogenic.

 

It is messy at the very least and possibly dangerous to your health if not close to lethal for small pets.

 

All this for a fairly marginal visual effect that needs a lot of maintenance and constant stopping for refills.

 

Oil smoke will never look like high pressure vented water vapour or diesel exhaust which is blue or black.

[a10driver]

hi guys

 

thanks for the info we think you are right about the smoke being harmfull

we were going to run them in the club room when we have a open night.

 

we never thought of it being harmfull

 

thanks for pointing it out

 

 

cheers a10