point motor using servo (turnout)

Ravindra Apr 28, 2020

  1. Ravindra

    Ravindra TrainBoard Member

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    I have been working on the custom point motor using servo so here is my first attempt.

    let me know if you want to improve anything, I will have another video for adding frog controls etc.

     
    TrinityJay and Sumner like this.
  2. Ravindra

    Ravindra TrainBoard Member

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    I know mostly all the hobby of Model railway is in the western countries where they can get supplies very easily. but anyone like me is not in that region will always face 2 problems. availability of the supply and the cost also. it is so much pain to realize that what you need for your model railway upgrade you have to import it and it will take a month to arrive and you have to face it every time whenever you need supply. so the easy solution is to build it if you can so you can save both money and time.

    one tortoise motor cost more than 25-40 US$ for one point motor and including shipping and taxes it may cost even more. and that's not economical for most of the non US UK modelers.

    so that's why I come up with this idea where it will give similar controls of Tortoise motor while costing only few dollars.

    so I see why people may not be interested in this solution. but i want to share it anyway for those who really need this.
     
  3. Sumner

    Sumner TrainBoard Member

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    Very nice idea and one that could be used for other items than turnout control. I'll probably build a few, thanks.

    I imagine you are going to control them with an Arduino. I took Dave Bodnar's cheap servo tester/controller idea and modified the circuit a little. The final product can be used to control the servo. It lets you easily set the limits of rotation and one doesn't have to be Arduino literate to use it. You do have to do a little soldering but that is it. It also provides indicator lights for which route the turnout is set for and changes the polarity of the frog. You can pick up...

    [​IMG]

    ... all the pieces for around $5....

    http://1fatgmc.com/RailRoad/Trackwork/page-7.html

    Sumner
     
  4. Ravindra

    Ravindra TrainBoard Member

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    That looks very good and almost the same as the one I am building. but it is missing one think I guess. how can I control the turnout digitally with JMRI etc.?

    I cannot see it registering the switching position for sensors.
     
  5. Sumner

    Sumner TrainBoard Member

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    What I linked to is a controller that you control the old fashion way with a switch on a control panel so no it isn't DCC compatible which means you can't control it with JMRI.

    I'm using DCC++, JMRI's Decoder Pro, JMRI throttle and phone throttles or Dave's wireless throttle but turnout control will be either manual with the switch machines I'm working on...

    http://1fatgmc.com/RailRoad/Trackwork/page-18.html

    ... or using servos as above with switches on control panels around the layout or on the fascia near the turnout.

    Sumner
     
  6. Ravindra

    Ravindra TrainBoard Member

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    Thanks Summer for the useful links.

    I am actually planning to add sensors to control turnouts digitally. I may not have physical switch to control it. and thats not required as I am planning mostly automation.
     
    Sumner likes this.
  7. Graff

    Graff TrainBoard Member

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    I'm a bit confused, why do you need linear motion to control a turnout with a servo?
    I use servo motor control on my layout, and the servo arm holds the piano wire like in this video:


    So easy, and no need for super precision when adjusting the servo.
     
  8. Ravindra

    Ravindra TrainBoard Member

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    That servo installation looks so easy and you are right it dos't need linear motion. but because its not linear if you look closely the wire moves vertically too. and that may cause derailment if you install it in center. may be we can install wire to the side of the tie bar to avoid that. but I actually needed other functions like switching frog and also switching signals/sensors so any other logic can be used based on the position of the turnout and things can be automated.
     
  9. Graff

    Graff TrainBoard Member

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    If you use an Arduino, you can actually change the frog polarity with relays connected to the Arduino.
     
  10. Ravindra

    Ravindra TrainBoard Member

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    Yes but doing that for all point based on the current state will be a too much work. I think putting one SPDT is much easy and quick solution.
     
  11. TrinityJay

    TrinityJay TrainBoard Member

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    Good ideas Ravindra, I actually subscribed to your channel after randomly finding that video a week or so back.

    Re: the Tortoise tension style vs lateral motion, I explored lateral motion for my own system because of how the Tortoise tension style setup at my club works. The setup is very similar to the video Graff posted, mechanically a 1st class lever, and we still have the odd issue with buzzing servos. When I posted my system over on Reddit I had a lot of people caution me on the use of servos with their own tales of woe over adjustments, saying they work fine for a while but eventually need constant retuning. Maybe nobody else uses 0.6mm wire and that is the secret, who knows.

    I am a bit confused here, in what way are you going to use a SPDT?
     
  12. Ravindra

    Ravindra TrainBoard Member

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    You can disable servo in Arduino as soon as it has switched the turnout. That way the servo will not make any buzzing sound. Having Little bit tension is handy whether using lever or lateral.

    I am using servos for last one year and didn't have to re adjust yet.
     
    Graff likes this.
  13. Ravindra

    Ravindra TrainBoard Member

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    Regarding SPDT. Actually I was referring to hardware switch instead of using Arduino to switch polarity for dcc signal at frogs.
     
    TrinityJay likes this.

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