Computer Controlled Fiddle Turntable

[Robin2]

I'm just wondering if anyone has experience of building a computer controlled rotating fiddle yard as I would like to get the benefit of their experience.

I'm building one for N-gauge with the turntable about 22" in diameter - actually it's a piece of melamine faced shelving 6" wide (and 22" long). I plan to have two tracks on it, and I have room for 4 altogether.

I want the computer to rotate it to the correct track and line up the tracks properly without manual intervention.

Thanks

 

...R

[Kenton]

Metalsmiths offer a DCC turntable solution that with some adaptation could probably be set up as a FY turntable.

[Robin2]

Thanks for that.

 

However I should have said that I don't want a DCC solution. (I am moving to the next generation - Battery Powered Radio Control).

 

To avoid confusion, the turntable won't be radio controlled - just the trains.

 

...R

 

 

Metalsmiths offer a DCC turntable solution that with some adaptation could probably be set up as a FY turntable.

[Kenton]

 

the turntable won't be radio controlled - just the trains.

Wow, in N-gauge you have my attention.

 

I guess if a turntable can be built to operate in DCC then it should be "relatively" simple to computer control one - (as a bit of a numpty here) I guess it will just come down to a stepper motor as drive and some form of accurate indexing all that should be theoretically controllable from a PC.

 

Have a good look around RMWeb someone on here has done a pretty spectacular vertical traverser and others have done flat bed traversers. The principles are much the same for a turntable, just a rotational control rather than linear.

[Robin2]

Always glad to evangelize -- see short video on post #85 on this page http://www.rmweb.co.uk/community/index.php?/topic/64616-battery-poweredradio-controlled-locos/page-4

 

Regarding turntables, I guess you haven't actually addressed the indexing issues yourself?

 

...R

 

 Wow, in N-gauge you have my attention.

I guess if a turntable can be built to operate in DCC then it should be "relatively" simple to computer control one - (as a bit of a numpty here) I guess it will just come down to a stepper motor as drive and some form of accurate indexing all that should be theoretically controllable from a PC.

Have a good look around RMWeb someone on here has done a pretty spectacular vertical traverser and others have done flat bed traversers. The principles are much the same for a turntable, just a rotational control rather than linear.

[Kenton]

 

Regarding turntables, I guess you haven't actually addressed the indexing issues yourself?

 

No, but I have seen that Metalsmith's 7mm one in use and it is impressive, there are also quite a few turntables out there on layouts that do handle indexing very well.

 

I don't see this as an insurmountable problem, nor do I see the use as a FY table in reality any different from a standard table.

[Suzie]

You don't want a DCC turntable, and you don't want radio control, the list of what you don't want is getting long - what specific control method do you want?

[Robin2]

Neither do I. But I would be interested to hear from someone who has actually done it as they may have ideas / solutions that I have not thought of.

 

...R

I don't see this as an insurmountable problem,

[Robin2]

I just realized that I have made a lot of progress with this but I haven't updated things here. I now have the turntables working using two servos on each turntable. The servos are controlled by an Arduino Uno microcontroller on the basis of instructions from a PC. One servo is used to rotate the turntable - it can move a bit more than 180 degrees so it can line up tracks at either end of my turntable. Obviously it can't do a complete revolution but that actually simplifies the wiring. The other servo is used to lift or lower a short metal arm which can make contact with metal indexing points on the turntable and complete a position detection circuit. When the Arduino sees that contact has been made it stops rotating the main servo. When the turntable must move to a different position the metal arm is first lifted out of the way.

 

I am also planning to use the Arduino to operate some points using servos and to detect the position of trains using Light Dependent Resistors under the track.

 

...R

[Simond]

Robin

 

Mrs D just ordered a geared stepper motor for my birthday pressie.

This will be fitted to my t/t so will add more to Jeff's thread in due course.

 

Would love to see some pix of your servo-driven beastie.

 

Best

SD

[Robin2]

Strangely (well not actually for me) it isn't complete yet - but there has been more work in the last few days so there may be pictures within a week.

 

I have converted a servo to continuous rotation because I needed more degrees of rotation and I have not tested that yet. I think it will be better because I now control the speed rather than the position and the position was never precise enough anyway so I have another position device.

 

...R

[andygif]

Here is a really nice solution to the computer controller turntable

 

http://blog.proto-pic.co.uk/2013/11/22/the-rolls-royce-of-arduino-controlled-model-railway-turntable-controller/

 

apart from buying components from these guys regularly, i have no connection to them.

 

though i not sure what the originating poster wants, is it a turntable or a fiddle yard that rotate ie a sector plate?