# Slow movement switch drive alternatives?



## Cougar Rock Rail (Jan 2, 2008)

Hi guys,

I started this thread because I didn't want to disrupt the thread on the Train-Li prodrive switch motors. 

Kevin mentioned that Traxxas makes a small waterproof servo so I checked the Traxxas website and they look like a very nice little product. If you were to combine that with a small function decoder that could power the servo directly (the Zimos can apparently do this) or other decoder with a voltage regulator circuit, then it seems to me to be a great alternative to the brushed motor/worm drive system. It would certainly be smaller.

Another alternate would be to use something like the proven LGB electromagnet drive but try to slow it down with some sort of dampening. I'm not sure how to do that yet but where there's a will, there's a way. Maybe one could use a little air piston at the switch site, and run an air line to a small bladder that would be compressed/decompressed by the LGB or other remotely hidden drive? 

Has anyone ever tried using servos or other systems?

Keith


----------



## Greg Elmassian (Jan 3, 2008)

Just to make sure I am not misunderstanding, I did not see that the Traxxas unit was waterproof, nor the electronics to drive it. Correct me if I misunderstood, I looked their web site over for a while. 

Actually, when you realize that you need the servo, and the servo electronics, and 1/4 of a decoder, the Prodrive is more compact, just as a comparison, the Traxxas system will not be smaller. (but you have to house the electronics some way, so you could make a trackside shanty or similar. 

I do agree that eliminating the brushes is a great idea, and I am sure waterproof servos can be found. 

On the solenoid driven side, a small air piston with a variable orfice could be used to dampen the motion, but most of the solenoids are not designed for continuous duty, so having to operate them longer will mean a change in powering, and possible overheating. 

If you want slow motion and reliability, go all air power like I did. Only one moving part, waterproof, reliable... the only downside is more expensive if you want remote control electronically. 

See my page for details on the parts used and how to run from DCC... 

http://www.elmassian.com/trains-mai...inmenu-101 


Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

Greg, I'm assuming when Traxxas says it is "waterproof", they mean waterproof. 

http://www.traxxas.com/products/accessories/trx_accessories_servos.htm 

I'm not sure what you mean by the servo electronics not being enclosed? All you have is the servo and a decoder, that's it. A function decoder the size of a piece of gum plus a micro servo seems much smaller than any of the switch drives. What am I missing? 

Keith


----------



## Greg Elmassian (Jan 3, 2008)

When Kevin first responded with his review from www.anemodel.com I did not see any mention of waterproofing.

Instead of admitting this, he just found a waterproof servo, and said "see, you're wrong Greg".

I just assumed that his comeback was something I had overlooked. 

This is where I was coming from. I did not notice that a different site was used to find a waterproof servo, since I thought Kevin would have responded, "oh you're right, none of their stuff is waterproof".

Looking at the anemodel site, their electronics is not waterproof, and you need the servo electronics and the separate DCC decoder.


So on this other site, there are waterproof servos, as I mentioned I'm sure existed.

The question is, are we talking R/C or DCC here? On the other thread, it was a DCC product, so I was assuming DCC here... (boy I gotta stop assuming!)


There are DCC decoders that will run servos, and none of them are waterproofed to my knowledge, but how hard is it to put it in a waterproof enclosure, not too difficult. I personally haven't seen any really small ones for DCC though.


If you are talking R/C control, then that's another set of hardware, of course.

So, I never questioned the existence of waterproof servos, it was questioning the suggested alternative on the other thread, which did not seem to have any advantage.

Back to this thread, I read up on the Zimo's handling of servos, seems to have enough flexibility to do the job, but they are pretty expensive. 

Have you found something inexpensive?

Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

I'm assuming DCC here, Greg. So all we would need is track power direct to decoder, servo plugs or is soldered to function decoder (assuming it has enough power to supply the 5V) and that should be it, no?


----------



## Greg Elmassian (Jan 3, 2008)

Tony's Trains is selling one: http://www.tonystrains.com/technews/td_mrc_newprd_0108.htm looks pretty inexpensive and 4 outputs for 4 servos apparently for $50

Zimo G scale decoders can run servos, but I think that's an expensive solution.

Here's one you can build: http://www.opendcc.de/elektronik/op...der_e.html 

ESU too: http://www.esu.eu/en/products/switc...lot-servo/

I've been thinking of playing with servos on DCC myself, not for turnouts, but some trackside animation.

Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

Running Servos with DCC is a piece of cake. I converted one of the LGB RhB hoppers to open/close using a servo and Massoth 8FL decoder. Not only can I run it to fixed end points, but I can control the gate proportionally using the throttle. That is one thing the Massoth decoders can do that none of the others I've seen can do. I did have to build a little voltage regulator circuit. Here's a video of it in operation: 

http://1stclass.mylargescale.com/cougarrockrail/Hopper servo system/hoppertrial.avi 

Here's a picture of the operation method: 

http://1stclass.mylargescale.com/co...vo system/Hopper servo system 006 resized.JPG 



Keith


----------



## Chip (Feb 11, 2008)

Keith:
I have ordered a Zimo 630 (11mm x 20mm x 3.5mm) to try the proportional throttle control on some things. I'll post the feedback. 

I run Zimo 82Es and 82Vs with Boehler switch motors. You have heard me blab about them. But
as George mentioned in the other thread, that is not an implementation with a decade warranty. 

Seems the Traxxas (US$29 and up) with an enclosure like Greg mentioned is a layup to try.

How much torque do you think is needed for a turnout? 

What are thinking about for your idea of "slow moving"? 


Between the Great Recession and end-of-life pricing by the competing manufacturers, options on the decoder side should grow.
That assumes these guys can stay in business. 



BTW, I am working this weekend to knockoff a hopper car like yours. We'll see if I can find or make

parts. 

Chip


----------



## Cougar Rock Rail (Jan 2, 2008)

Hi Chip, 

I look forward to your knockoff!  

For a turnout I can't see needing much torque, since there should be almost no resistance and assuming a spring type servo saver is used even the smallest servo should be fine. 

Keith


----------



## Greg Elmassian (Jan 3, 2008)

Actually you want a fair amount of "holding torque" on a lot of switches. If your switch is in really good shape first, then no, but a lot of out of the box switches need some help. 

Also, grit and ballast can definitely "Ask" for more torque! 

I look forwards to more info, how much is that Massoth 8FL ? 

Please post more pix of the hopper! 


Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

You are right that it would be best to have some sort of eccentric motion to take the pressure off the servo near the end position. It's important that the servo controller moves the servo to the end position and cuts the power so it's not fighting and using up current until it's given the command to move again. Sorry Greg I can't remember how much I paid for my 8FL a while back...have to look back. 

Here is an overall picture showing where I mounted the decoder and voltage reducer board. As you can see, the board is pretty big and clunky because it was the first one I've made and I wanted screw terminals. The decoder is very small relative to the board. LGB ball bearing wheels pickup the power. 

http://1stclass.mylargescale.com/co...vo system/Hopper servo system 001 resized.JPG


----------



## Greg Elmassian (Jan 3, 2008)

Nice install.... I looked up the decoder, list is $50, not too bad, may be one of the cheaper DCC servo capable decoders.

Will have to try a few.

I think there is an opportunity here. Would be easy to completely encapsulate.


Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

Yes it was a happy day when I discovered the 8FL! Have a read of the manual on the Massoth website--it's a very powerful little decoder. The ability to control it proportionally is the best feature of all, though. This allows it to be used to run live steamers and all sorts of controls where you want more than just end positions. 

Keith


----------



## Trains West (Oct 4, 2008)

you could use a tortoise machine.....no need for servos or drivers works with stanard switch decoder and is low draw


----------



## Greg Elmassian (Jan 3, 2008)

Yep, many DCC decoders will run a tortise, but I think we were looking at waterproof solutions. It's well understood that putting a waterproof enclosure around something not waterproof works. 

That Massoth decoder is tiny, and waterproof servos seem like a great idea. Will download the Massoth manual and see what programming options are available, but all you need is limit points and speed I think. 

Regards, Greg


----------



## Cougar Rock Rail (Jan 2, 2008)

If my memory serves me correctly, you can program end points, speed, reverse the direction (if it is a digital servo) or use proportional control for two servos, plus 6 more functions for lights or whatever. There really is no end to the animation capabilities with DCC...another reason I love it. What a great hobby! 

Keith


----------



## Chip (Feb 11, 2008)

The Zimo 82E is about $30 and the 82V (for 2 turnout motors or 4 servos) is $45. About half the cost per turnout for two.


They are slightly smaller than the 8FL, but either is small enough for this application.

They also let you control the voltage by pulse (fixed though). That was what drove me to use it without
having to do the volatge circuit to drive the Boehler motors. Not an issue with the servo idea.

The proportional control on the 8FL is a biggie.

One minor thing of note: the Zimo items have Railcom feedback if someday you
want to know if the command you sent got there. As it is today, you can only listenor check the device. 

As a Massoth user and a fan of the Navigator, it looks like we will be waiting a while for that. 
I wouldn't want to pay a royalty either.


----------



## East Broad Top (Dec 29, 2007)

When Kevin first responded with his review from www.anemodel.com I did not see any mention of waterproofing. 

Instead of admitting this, he just found a waterproof servo, and said "see, you're wrong Greg". 

Greg, here's what I wrote: "They use regular R/C servos to actually move the switch points, so if you can find waterproof servos, the control electronics can be safely housed out of the weather." 

Nowhere in that sentence--or in any other--do I make any assertion that the controls themselves are waterproof. I say the control electronics can be safely housed out of the weather, meaning away from the switch being thrown. The idea is for the user to house the controls in a garage, lineside building, or wherever they can't get wet and run a servo extension cord from the controls out into the elements to the servo, which will invariably get wet--hence the need for that one piece of the puzzle to be waterproof. 

If you read the review, under the "con" section, is the following. "Not intended for outdoor use." In fact, it's the only thing listed there. I may not be teaching English at Harvard, but I'm loathe to understand how a statement like that can in any way be interpreted as to imply any level of waterproofing on the product. Being that I wrote that particular review, why would I then come on this forum and suggest otherwise? 

Later, 

K


----------

