My neighbor is a mechanical design genius. With his help (mostly his), we have designed and built a 24" long turntable to fit on my layout. We have spent almost 1 year designing in Design Spark (Space Claim freebee) and programming Arduino's for control. At the present time, we are in the middle of finishing a major re-design to incorporate assembly using full connectorization instead of endless hours of difficult soldering.

If there is any interest in this project, I will take some pictures of the assembly process and videos of the turntable in operation. The beauty of this design is that it has many more features than those currently on the market and can be made for approximately $100 worth of parts. However, you must have some tools and a 3D printer.

Ken

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Foundation-Bottom ViewFoundation-Top ViewOK, let's start slow and at the bottom. This will take some time to get all the parts laid out with the accompanying explanations.

The 2 pic's I have enclosed are from our 3D design tool which is Design Spark (free version of Space Claim). It shows the foundation for the turntable and requires a little history to understand.

I started building my layout several years ago (after tooooo many years waiting). At that time I had a turntable that I purchased 25-30 years ago along with a 3-bay engine house. These two items dictated one end of my layout. The turntable came with a top section that was trapezoidal shaped (which explains the top section of what you see in these pic's). I had made a cutout to accommodate the turntable in a 4' x 8' piece of plywood. The turntable was DC motor driven with optical pickups mounted on the underside to stop the table at designated positions. In operation (and I had 9 positions for the stops) there was a problem when moving in the opposite direction from the setup direction (a condition known as hysteresis), which resulted in rotational misalignments. In addition, large engines would cause the track bed to dip enough to also cause derailments. So between misalignment and dipping problems, I was not happy with the old turntable.

About a year ago, my neighbor, who is a retired mechanical design genius, was bored and decided to help. He came up with the idea of using stepper motors and a lazy susan, the latter being a way to eliminate the tilting due to the small 'bearing' surface in the old turntable and the former providing great alignment precision.

The first step was to cut out the trapezoidal top piece followed by making a 24" diameter disc out of plywood using a router. The we ordered a 6-wire slipring to provide electrical connection to the rotating table. What you see in the pic's is a 3D simulation of what we have made (at this time no 3D printing involved).

I will take some pic's of the old turntable and of the actual top and bottom foundations and include at the next posting. One last item at this stage. My neighbor them took the stepper motor, added a 24VDC power supply and a stepper driver and designed and built a control box which I will show in the next posting.

All of this meant a new turntable and so emerged the need and use of 3D printers.

 

 

 

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Mike, that's the best part of all of this. I have seen the Ross TT at shows and they are very nice, but very pricey. Our TT cost (in parts) less than $200. However, you do need a $325 3D printer and a lot of time on YouTube learning how to use the design and slicing programs and then how to program an Arduino (the controller). In the end, we have a TT that is loaded with animation (as you will see later) and provides the same level of functionality as those on the market.

As to my previous post, here are some pics's of the actual TT top, disc, slipring, bottom mount, stepper motor, and control box. The mount for the stepper motor was the 1st 3D part, and the control box was the 2nd. I have also included a vid of my friends design for the draw bridge that will provide connection from an outside line to an inside line so as not to block a bedroom door. All (except the stepper motor) done with a 3D printer (just a little teaser. The close ups of the stepper on the underside show the gears that were added to provide even finer rotational resolution. The square blocks on the bottom of the table were spacers to provide the well that the TT mounts in (done for realism).  And I threw in a couple pic's of my very incomplete layout--too much time on TT and learning new stuff.

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Sorry about the delay, but I've been working on wiring diagrams for the new design--the redesigned parts of which I will show in my subsequent postings.  This batch of pic's shows the bottom section of the turntable (TT). It includes the base which was pictured on the previous posting showing it mounted of the 24" disc. Also included are the 2 foundation sections, the 3 track mount sections, lamp parts, fences, house & roof, and a few other parts (servo mount, connector array, etc.) that will make more sense when assembled.

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I apologize for the delay, but wiring takes forever and I discovered one of the very small parts from the original design didn't work with the re-design (it is the LED holder assy. for the lamp in the house). I have included pic's of the individual parts of the lower portion of the turntable (TT), and then follow up with each stage of assembly (except all the wiring--with 2 exceptions--was completed first. I have shown the wiring on the underside of the foundation/track bed assy. with wiring to/from the connector array to the Arduino mount, lamp assy.'s, servo, slip ring connector, and Gantry connector. I then show the new connector approach to the lamps/lamp base, the man mount, man in the house, house assy., and a partial of the entire lower portion of the TT. More to come, but the Gantry assy. wiring takes a lot of time, and we may be looking to re-design in that area also.

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Here is the thing with the .stl files. There are so many (maybe 100), and we keep modifying and updating, and sometimes 5 versions to get it right, I'm not sure if that would be the best approach. Secondly, it would be a nightmare to try and figure out what parts go where. Thirdly, you need at least a Crealty CR-10 or similar to print the larger parts due to size (some over 12" in length). So, after I am certain none of the train companies would be interested, and with the ok from my friend (who is the main designer), I will see if I can post the entire Turntable file as an .rsdoc (Design Spark) file, and you can created your own .stl files. The other issue is necessity of building a control box for the main TT driver, and then to understand the alignment/calibration and operation programs--they are designed to work with Steve's control box and are his designs. I have designed the TT animation programs for the lower TT operation and Gantry operation.

Well after lots of wiring, the lower portion of the TT is ready for show. However, I need to move a few things around underneath so I have not installed the house and I have a protective 'sleeve' over the house LED/dome assy so as not to damage it when TT is turned over. The operation in the video shows the TT condition when power is 1st applied, then when a command is received from the control box (simulated here) that the TT is about to move, the lamps flashing, man moving out of house (missing), and alarm sounding, all during TT movement. And finally lamps back to non-flashing, alarm off, and man back in house once designated position is reached.

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TT Operation (lower)

Well finally, the TT is finished (sort of). All the functions are complete with the exception of expanding the sound function to have some voice announcements. Also we are trying to figure out how to put a door on the house. First I will show some pictures of the TT, and then a couple of videos of the TT in operation. They are not the best, but to get everything in, I had to use a larger screen res. and am limited to 100M per video. So I broke up the video into 2 parts---first the pics.

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This 1st vid is the lower portion of the TT action. When a cmd is received from the control box (simulated here), the lamps start flashing red/wht, the motion alarm sounds, and the man comes out of the house and then scans both directions. Continues until cmd is turned off (motion has completed).

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TT Lower Motion

Thanks for sharing this project, I will be following and gathering ideas for my own custom turntable someday.  And I do have a 3D printer and enjoy working on automations using Arduino and Raspberry Pi.  

She caught the Katy and left me a mule to ride...

 

We have a design and operational proto. of the door with actuation and will be reprinting and remounting a bunch of stuff to install. We also decided that the LED on the house floor looks dumb, so have designed a lamp to be placed in a corner--removing the floor LED. I will post when complete. Then we will install the TT in the layout and make a video of it in operation in its' intended environment. Patience please--we're old & slow.

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