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Ultrasonic "smoke" generator?

911 Views 44 Replies 10 Participants Last post by  gunrunnerjohn
Recently, I went searching for a cheap "smoke" generator, most immediately to enhance an existing camping scene, but potentially for chimney or vehicle smoke, etc. The $50 price tag for an MTH replacement smoke unit was enough to give me pause, and the roughly $10 cost for a cheap R/C tank smoke generator caught my eye, until I came across some very inexpensive USB-powered ultrasonic mist generators, about three bucks each total cost if delivered by slow boat. I already have one on order, with which I plan to experiment, but I was wondering if anyone had already attempted to incorporate something similar on their layouts?
As I see it, the benefits of such a unit are:
  • It uses distilled or tap water, rather than consuming smoke fluid.
  • It does not heat up, so fewer heat-related installation precautions or potential issues.
  • It will turn itself off if it runs dry, and in any event will likely have no serious consequences even if it stays on without water.

The potential shortcomings I've considered:
  • The unit is not fan-driven, so it might be harder to cover or disguise the unit and still have it produce vapor.
  • The vapor will not be significantly heated, so it might not behave like true heat-driven smoke (perhaps more like low-hanging fog?). This might be overcome by adding an enclosure and a small fan, but that adds to the complexity of fabrication and cost.

So, anyone tried to use one of these units? If so, what was your experience?
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I'm curious if it will work so I'll be tagging along as I like more realistic smoke and I can't stand the smell of smoke fluid 馃ぎ
We have an inexpensive humidifier that is based on a nebulizer. It produces a ton of vapor. It sure seems like such a thing would make great smoke effects for our trains, but I would worry about condensation... This past winter, I set the humidifier on the floor, next to a cold air return for our furnace... the grate over the cold air intake soon was covered in sweat.
We have an inexpensive humidifier that is based on a nebulizer. It produces a ton of vapor. It sure seems like such a thing would make great smoke effects for our trains, but I would worry about condensation... This past winter, I set the humidifier on the floor, next to a cold air return for our furnace... the grate over the cold air intake soon was covered in sweat.
Yeah, That's basically what this is, a small, personal nebulizer that uses an ultrasonic transducer to spray mist-sized droplets, which of course evaporate and raise the ambient humidity somewhat. I've already concluded it's unlikely to replace traditional smoke units in rolling stock (putting water and mist near the motor doesn't seem like a good idea!) even if I could get it to fit, but my thought is it might do for stationary accessory use.
I have a friend that made a pretty large atomic power plant with a cooling tower. He uses a custom made pan with a number of ultrasonic transducers in it to simulate the fog from the tower, very realistic. He does have a large computer fan moving the vapor out, it is fairly impressive.
I have a friend that made a pretty large atomic power plant with a cooling tower. He uses a custom made pan with a number of ultrasonic transducers in it to simulate the fog from the tower, very realistic. He does have a large computer fan moving the vapor out, it is fairly impressive.
Thanks, GRJ. Yeah, I can see how a nuclear cooling tower would lend itself better to simulation using the transducers, since the prototype also produces relatively cool water vapor rather than smoke. If I end up using a transducer, I may end up having to enclose it in a plastic box, and add a small fan (more like those in notebook computers) to move the vapor produced through a plastic tube to where I want it. My thought was to adjust the supply voltage to get the desired air flow, but I'm still worried about the long-term effect of pouring water vapor and droplets over and through the landscaping to exit through the 'campfire'. Ah, well, I guess that's why they call it an "experiment"!
I have a Comfort Zone Digital Ultrasonic Humidifier I use.

This unit pumps out the water vapor to look like smoke however, it dissipates very quickly.
The longest vapor trail I saw coming out of the nozzle can't be more than 6 inch's/15cm as it turns into brief puffs of clouds less than a foot away...and that's on high.
I was thinking on using this unit to route tubes to chimneys in a town but I do not think the vapor would be around long enough to make it look like smoke.
I might do a future test.
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I have a Comfort Zone Digital Ultrasonic Humidifier I use.
This unit pumps out the water vapor to look like smoke however, it dissipates very quickly.
The longest vapor trail I saw coming out of the nozzle can't be more than 6 inch's/15cm as it turns into brief puffs of clouds less than a foot away...and that's on high.
I was thinking on using this unit to route tubes to chimneys in a town but I do not think the vapor would be around long enough to make it look like smoke.
I might do a future test.
Yeah, I think the tech used is the same, though your humidifier might also use a fan to circulate the moisture generated, since that's its design function. By the evidence of the videos, the devices I'm looking at also seem to produce a plume of mist of about a foot or so, which should be sufficient for my 'campfire smoke' or your chimneys. As I noted earlier, I may end up with some sort of forced-air distribution, which might preserve the mist long enough to be visible above the modeled 'source'. I have one on order, so we'll see . . .馃
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Not sure which low-cost (a couple bucks) ultrasonic unit you bought, but another benefit is rapid-instantaneous on-off "smoke" useful in some smoke/steam animations such as engine puffing or synchronized whistle steam. The electronics to generate such using traditional heated smoke fluid methods with motorized "fan" can be complex. If you are of the DIY'er persuasion and comfortable mucking around with electronic components, we can explore methods of controlling these fascinating ultrasonic misters for model train applications.

unfortunately an ultrasonic mister will not make 'smoke' as dense as a heater type will ... only about half of that type of generator , and the 'run' time will be quite a bit less ...
i tried qute a few different varities to make an acceptable smoke generator, but failed..
but carry on with the project ...
Recently, I went searching for a cheap "smoke" generator, most immediately to enhance an existing camping scene, but potentially for chimney or vehicle smoke, etc. The $50 price tag for an MTH replacement smoke unit was enough to give me pause, and the roughly $10 cost for a cheap R/C tank smoke generator caught my eye, until I came across some very inexpensive USB-powered ultrasonic mist generators, about three bucks each total cost if delivered by slow boat. I already have one on order, with which I plan to experiment, but I was wondering if anyone had already attempted to incorporate something similar on their layouts?
As I see it, the benefits of such a unit are:
  • It uses distilled or tap water, rather than consuming smoke fluid.
  • It does not heat up, so fewer heat-related installation precautions or potential issues.
  • It will turn itself off if it runs dry, and in any event will likely have no serious consequences even if it stays on without water.

The potential shortcomings I've considered:
  • The unit is not fan-driven, so it might be harder to cover or disguise the unit and still have it produce vapor.
  • The vapor will not be significantly heated, so it might not behave like true heat-driven smoke (perhaps more like low-hanging fog?). This might be overcome by adding an enclosure and a small fan, but that adds to the complexity of fabrication and cost.

So, anyone tried to use one of these units? If so, what was your experience?
That is not a traditional smoke unit, if its uses water that鈥檚 a small humidity generator. I once hooked one up to a smokestack for a factory. Ive hearted distilled water works best as standard tap water will make the produced mist sink and collect on locos cars and ground cover. Not a big problem, but can damage tin pieces over time.
Recently, I went searching for a cheap "smoke" generator, most immediately to enhance an existing camping scene, but potentially for chimney or vehicle smoke, etc. The $50 price tag for an MTH replacement smoke unit was enough to give me pause....
$50 for a traditional heated smoke generator, plus the cost of the arguably unique "mineral oil" or whatever smoke fluid can indeed cause pause.

Ultrasonic mister technology as used in consumer nebulizers, humidifiers, etc. also have a variant in "aromatherapy" where the atomized fluid is NOT pure/distilled water. For example, Lavender oil is quite popular for soothing stressed nerves using ultrasonic atomizer technology.

IMHO, most if not all technological innovation in model train technology are because we co-opt bits and scraps from mainstream consumer applications manufactured in the billions of units. As I see it, there has never been a practical/realistic implementation of black smoke which is arguably the holy grail of model train smoke modeling.

Sorry guys, I am new to the MTF forum. If the MTF gurus have deemed ultrasonic vaporizing technology a non-starter for model train applications and have already voted it off the island, then so be it. I apologize and will stand back and stand down.
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IMHO, most if not all technological innovation in model train technology are because we co-opt bits and scraps from mainstream consumer applications manufactured in the billions of units. As I see it, there has never been a practical/realistic implementation of black smoke which is arguably the holy grail of model train smoke modeling.

Sorry guys, I am new to the MTF forum. If the MTF gurus have deemed ultrasonic vaporizing technology a non-starter for model train applications and have already voted it off the island, then so be it. I apologize and will stand back and stand down.
Thanks for your valuable input, Stan -- AFAIK, there's no real consensus for or against such ultrasonic transducers, at least none that I've yet seen, and your suggestion and video about using their virtually instantaneous on-off capability is intriguing to say the least. ISTM that it would be possible to create an ultrasonic smoke generator of approximately the same dimensions as the traditional heated element ones (even identical, for retrofitting purposes), that can be tied into a control system for on-off activation pulses timed to match the speed of the wheels.

For my part, I'm still waiting for the 'slow boat' to arrive with my test unit so I can begin experimenting myself, but so far, the comments I'm seeing (including your own) have been very encouraging. As I said, I have a particular accessory use in mind, but the ability to draw a lot less power yet produce reasonably realistic smoke (albeit white rather than black!) from locomotives using only distilled water is intriguing, to say the least.
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the ultrasonic vapour generators that i tried drew about 200mw, at 10 volts what does your version draw ??
$50 for a traditional heated smoke generator, plus the cost of the arguably unique "mineral oil" or whatever smoke fluid can indeed cause pause.

Ultrasonic mister technology as used in consumer nebulizers, humidifiers, etc. also have a variant in "aromatherapy" where the atomized fluid is NOT pure/distilled water. For example, Lavender oil is quite popular for soothing stressed nerves using ultrasonic atomizer technology.

IMHO, most if not all technological innovation in model train technology are because we co-opt bits and scraps from mainstream consumer applications manufactured in the billions of units. As I see it, there has never been a practical/realistic implementation of black smoke which is arguably the holy grail of model train smoke modeling.

Sorry guys, I am new to the MTF forum. If the MTF gurus have deemed ultrasonic vaporizing technology a non-starter for model train applications and have already voted it off the island, then so be it. I apologize and will stand back and stand down.
First off Stan, welcome to the forum. :)

There is no voting by "gurus" that can vote anything off the island, one of the great things about a truly open discussion forum is it's "open". ;)

As for black smoke, so far the only way that has been proposed is using some sort of particulate matter, that would be a nightmare in the train room. I'd love to see a way to do it, but I haven't seen a practical way as of now.

I wonder about cleaning ultrasonic misting equipment that doesn't use distilled water. I know the little humidifiers my daughter has require a vinegar bath regularly to remove the scale from using plain tap water.

I think one thing that has inhibited the adoption of water based "smoke" is the worry about rust and corrosion from the moisture. Also, most of the untrasonic emitters seem to be a bit large for model train use.
you can get ultrasonic vapour emitters that are the right size for HO scale, i -assume- it is just as easy to get them sized appropriately for O scale [and others] ..
i never calculated the vapour or condensate deposited on the layout, i just gave up on the project as the vapour was not very long lasting, and seemed very thin compared to liquid smoke versions
As for black smoke, so far the only way that has been proposed is using some sort of particulate matter, that would be a nightmare in the train room.
OTOH, think of all the time you'd save by not having to dry brush smoke stains on tunnel portals, or weather grime onto all your rolling stock and trackside buildings and other accessories. Self-applying grime -- how prototypical! :sneaky:
OTOH, think of all the time you'd save by not having to dry brush smoke stains on tunnel portals, or weather grime onto all your rolling stock and trackside buildings and other accessories. Self-applying grime -- how prototypical! :sneaky:
Well, that is how the grime gets on the tunnel portals! 馃ぃ
I attended a small N-scale show this weekend, and the club that sponsored the show had their modular layout all setup.

One of the scenes was a building that was on fire. They had built in a humidifier inside the building, so the "smoke" was billowing out the widows. It was really a neat scene. It was on the whole time I was there, and there was no buildup of water than was visibly noticeable.
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