Forums » Electronics

List of newest posts

    • April 23, 2018 9:13 PM EDT
    • Wait I thought they banned PCBs cause they were killing the fish and other things as well.

    • April 23, 2018 8:39 PM EDT
    • Bob McCown said:

      I’m supposed to have a goal?  Now you tell me.  

       

      Seriously though I eventually want occupancy and route signals, running ABS and/or CTC.  At the rate I’m going it’ll never happen, but it’s a fun experiment.

      The ride is the thing, isn't it?  

    • April 23, 2018 8:25 PM EDT
    • I’m supposed to have a goal?  Now you tell me.  

       

      Seriously though I eventually want occupancy and route signals, running ABS and/or CTC.  At the rate I’m going it’ll never happen, but it’s a fun experiment.

    • April 23, 2018 8:00 PM EDT
    • A long and winding road.

       

      What's the ultimate goal?

    • April 23, 2018 7:47 PM EDT
    • Another small update.  I had some custom PCBs made last year and I finally assembked one completely.  

       

    • April 20, 2018 8:38 PM EDT
    • Bob McCown said:

      A couple of years ago at York, I think it was Cliff Jennings had a prototype of a servo-based switch machine at the Drag n Brag.

       

      Yep, and thanks Bob!

       

      It was a heavy-duty servo (not the 9g), in a sealed container. I was trying to look that thread up, but Bob, it seems none of my buttons are working. Links yes, buttons nyet.

       

      Those 9g servos are impressive though, for what they do in their size. The Train Li switch machines use them (I have a bunch). 

      https://www.trainli.com/switch-drives-stands-86/tl10-20004-p-312

       

      The drive design isn't very robust though; and the units are not sealed. That's why I went on my own design journey. But after that York show 2 years ago, I've not done much else on the topic. But best wishes Dennis with your endeavor, and thanks for the nice product links.

       

      Cliff

    • April 20, 2018 6:28 PM EDT
    • Are you guys using (or proposing to use) servos outdoors?  I’m using Tortoises for my indoor turnouts, but starting to consider my outdoor options. I like the idea of servos, but not sure about weatherproofing them. 

    • April 20, 2018 4:26 PM EDT
    • I was pondering either using a z spring like I do with the barrel bolts, and just over throw a bit.   Possibly a magnetic or spring servo saver would work too.  Magnetic ones may do the same thing. Not sure, I haven’t got beyond the thought stage myself.  

    • April 20, 2018 4:09 PM EDT
    • I see one problem, is maintaining pressure to keep the switch points hard against the stock rails.

       

      I don't see how this is done without the servo motor using current to keep up this pressure. I guess if there was a worm drive somewhere it could work.

       

      Can someone explain how a servo can maintain pressure without consuming current?

       

      Greg

    • April 20, 2018 12:03 PM EDT
    • Neat.  I'd like to find a small electromechanical clutch so I can turn on and off local control.   I wonder if the Dagu ones could be modified slightly.  Hrm...

    • April 20, 2018 11:48 AM EDT
    • Yes, mine has a handle for manual operation.

       

      I've since changed the design slightly and use a bell crank so I can rotate the servo 90 degrees. That lets the handle move right to left instead of in and out toward the track.

    • April 20, 2018 11:31 AM EDT
    • Martin Sant said:

      I'm using a home made magnetic clutch on my waterproof outdoor servos.  It lets me have a bit of 'slop' in the final positions.

      They make them for the little servos:

      https://robosavvy.com/store/dagu-magnetic-servo-clutches-for-miniature-servos.html

      perhaps they would help

       

      Ive been pondering how to make a "works like the prototype" switch machine for outdoors.  I'd like the ability to throw it remotely, electronically, but then also allow local operators to throw it via a ground throw (not pushbuttons, this would be trivial, and has been solved already).  Ive looked at the idea of a magnetic clutch or two to do this.

    • April 20, 2018 10:26 AM EDT
    • I have two turnouts I am considering using a servo on. this would eliminate a constant duck under situation, especially when operating alone. looking forward to some recommendations.

       

      Al P.

    • April 20, 2018 9:38 AM EDT
    • A couple of years ago at York, I think it was Cliff Jennings had a prototype of a servo-based switch machine at the Drag n Brag.

       

    • April 20, 2018 9:12 AM EDT
    • Just watched a video yesterday and answered one of my questions about servo limits.  A servo uses a potentiometer feedback to tell the position. Well the value of the Pots are all not equal and you really have to test each servo to find the limits. that is if you are using the full 180 degree range. Also will help you find the true 90 degree center and add that to your sketch for each servo.

      A simple sketch in putting in the step value will let you know the limits.

       

      It is a 23 minute video with a lot of information, at about 12 minutes he explains the servo testing.

    • April 19, 2018 2:05 PM EDT
    • Michael Moradzadeh said:

      It would seem to me with an Arduino that you could also cut off power to the servo once you have completed the move.

      That's what I do in my locomotives (remote coupler servos).  Just put a power MOSFET in the ground line and tie the gate to a pin on the Arduino.  The reason I do it on the locos is that the servos chatter when the traction motors are generating noise.  Probably not a concern with turnouts.  Of course it also saves power.  

       

    • April 19, 2018 12:52 PM EDT
    • It would seem to me with an Arduino that you could also cut off power to the servo once you have completed the move.